Chapter 6: Link Layer and LANs

Chapter 6 Link Layer and LANs

UG3 Computer Communications amp Networks(COMN)

Mahesh Marinamaheshedacuk

Slides copyright of Kurose and Ross

Link layer introduction

terminologybull hosts and routers nodesbull communication channels that

connect adjacent nodes along communication path linksndash wired linksndash wireless linksndash LANs

bull layer-2 packet frameencapsulates datagram

data-link layer has responsibility of transferring datagram from one node to physically adjacent node over a link

6-2Link Layer and LANs

Link layer context

bull datagram transferred by different link protocols over different linksndash eg Ethernet on first link

frame relay on intermediate links 80211 on last link

bull each link protocol provides different servicesndash eg may or may not

provide rdt over link

transportation analogybull trip from Princeton to Lausanne

ndash limo Princeton to JFKndash plane JFK to Genevandash train Geneva to Lausanne

bull tourist = datagrambull transport segment =

communication linkbull transportation mode = link

layer protocolbull travel agent = routing

algorithm


Link layer services

bull framing link accessndash encapsulate datagram into frame adding header trailerndash channel access if shared mediumndash ldquoMACrdquo addresses used in frame headers to identify

source destination bull different from IP address

bull reliable delivery between adjacent nodesndash we learned how to do this already (chapter 3)ndash seldom used on low bit-error link (fiber some twisted

pair)ndash wireless links high error rates

bull Q why both link-level and end-end reliability


bull flow controlndash pacing between adjacent sending and receiving nodes

bull error detection ndash errors caused by signal attenuation noise ndash receiver detects presence of errors

bull signals sender for retransmission or drops frame

bull error correctionndash receiver identifies and corrects bit error(s) without resorting to

retransmission

bull half-duplex and full-duplexndash with half duplex nodes at both ends of link can transmit but not

at same time

Link layer services (more)


Where is the link layer implementedbull in each and every hostbull link layer implemented in ldquoadaptorrdquo (aka network interface card NIC) or on a chipndash Ethernet card 80211 card

Ethernet chipsetndash implements link physical

layerbull attaches into hostrsquos system

busesbull combination of hardware

software firmware

controller

physicaltransmission

cpu memory

host bus (eg PCI)

network adaptercard

applicationtransportnetworklink

linkphysical


Adaptors communicating

bull sending sidendash encapsulates datagram in

framendash adds error checking bits

rdt flow control etc

bull receiving sidendash looks for errors rdt flow

control etcndash extracts datagram passes

to upper layer at receiving side

controller controller

sending host receiving host

datagram datagram

datagram

frame


Error detection

EDC= Error Detection and Correction bits (redundancy)D = Data protected by error checking may include header fields

bull Error detection not 100 reliablebull protocol may miss some errors but rarelybull larger EDC field yields better detection and correction

otherwise


Parity checking

single bit paritysect detect single bit

errors

two-dimensional bit paritysect detect and correct single bit errors

0 0


Check out the online interactive exercises for more examples httpgaiacsumassedukurose_rossinteractive

Internet checksum (review)

senderbull treat segment contents

as sequence of 16-bit integers

bull checksum addition (1rsquos complement sum) of segment contents

bull sender puts checksum value into UDP checksum field

receiverbull compute checksum of

received segmentbull check if computed

checksum equals checksum field valuendash NO - error detectedndash YES - no error detected

But maybe errors nonetheless

goal detect ldquoerrorsrdquo (eg flipped bits) in transmitted packet (note used at transportnetwork layers only)


Cyclic redundancy checkbull more powerful error-detection codingbull view data bits D as a binary numberbull choose r+1 bit pattern (generator) Gbull goal choose r CRC bits R such that

ndash ltDRgt exactly divisible by G (modulo 2) ndash receiver knows G divides ltDRgt by G If non-zero remainder

error detectedndash can detect all burst errors less than r+1 bits

bull widely used in practice (Ethernet 80211 WiFi ATM)


CRC example

wantD2r XOR R = nG

equivalentlyD2r = nG XOR R

equivalentlyif we divide D2r by G want remainder R to satisfy

R = remainder[ ]D2r

G



Multiple access links protocolstwo types of ldquolinksrdquobull point-to-point

ndash PPP for dial-up accessndash point-to-point link between Ethernet switch host

bull broadcast (shared wire or medium)ndash old-fashioned Ethernetndash upstream HFCndash 80211 wireless LAN

shared wire (eg cabled Ethernet)

shared RF(eg 80211 WiFi)

shared RF(satellite)

humans at acocktail party

(shared air acoustical)


Multiple access protocols

bull single shared broadcast channel bull two or more simultaneous transmissions by nodes interference

ndash collision if node receives two or more signals at the same time

multiple access protocolbull distributed algorithm that determines how nodes share

channel ie determine when node can transmitbull communication about channel sharing must use channel itself

ndash no out-of-band channel for coordination


An ideal multiple access protocol

given broadcast channel of rate R bpsdesiderata

1 when one node wants to transmit it can send at rate R2 when M nodes want to transmit each can send at average

rate RM3 fully decentralized

bull no special node to coordinate transmissionsbull no synchronization of clocks slots

4 simple


MAC protocols taxonomy

three broad classesbull channel partitioning

ndash divide channel into smaller ldquopiecesrdquo (time slots frequency code)ndash allocate piece to node for exclusive use

bull random accessndash channel not divided allow collisionsndash ldquorecoverrdquo from collisions

bull ldquotaking turnsrdquondash nodes take turns but nodes with more to send can take longer

turns


Channel partitioning MAC protocols TDMA

TDMA time division multiple accessbull access to channel in rounds bull each station gets fixed length slot (length = packet

transmission time) in each round bull unused slots go idle bull example 6-station LAN 134 have packets to

send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe


FDMA frequency division multiple access bull channel spectrum divided into frequency bandsbull each station assigned fixed frequency bandbull unused transmission time in frequency bands go idle bull example 6-station LAN 134 have packet to send frequency

bands 256 idle

frequ

ency

ban

ds

time

FDM cable

Channel partitioning MAC protocols FDMA


Random access protocols

bull when node has packet to sendndash transmit at full channel data rate Rndash no a priori coordination among nodes

bull two or more transmitting nodes ldquocollisionrdquobull random access MAC protocol specifies

ndash how to detect collisionsndash how to recover from collisions (eg via delayed

retransmissions)bull examples of random access MAC protocols

ndash slotted ALOHAndash ALOHAndash CSMA CSMACD CSMACA


Slotted ALOHA

assumptionsbull all frames same sizebull time divided into equal size

slots (time to transmit 1 frame)

bull nodes start to transmit only slot beginning

bull nodes are synchronizedbull if 2 or more nodes transmit

in slot all nodes detect collision

operationbull when node obtains fresh

frame transmits in next slotndash if no collision node can send

new frame in next slotndash if collision node retransmits

frame in each subsequent slot with prob p until success


Prosbull single active node can

continuously transmit at full rate of channel

bull highly decentralized only slots in nodes need to be in sync

bull simple

Consbull collisions wasting slotsbull idle slotsbull nodes may be able to

detect collision in less than time to transmit packet

bull clock synchronization

Slotted ALOHA1 1 1 1

2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E


bull suppose N nodes with many frames to send each transmits in slot with probability p

bull prob that given node has success in a slot = p(1-p)N-1

bull prob that any node has a success = Np(1-p)N-1

bull max efficiency find p that maximizes Np(1-p)N-1

bull for many nodes take limit of Np(1-p)N-1 as N goes to infinity givesmax efficiency = 1e = 37

efficiency long-run fraction of successful slots (many nodes all with many frames to send)

at best channelused for useful transmissions 37of time

Slotted ALOHA efficiency


Pure (unslotted) ALOHA

bull unslotted Aloha simpler no synchronizationbull when frame first arrives

ndash transmit immediately bull collision probability increases

ndash frame sent at t0 collides with other frames sent in [t0-1t0+1]


Pure ALOHA efficiency

P(success by given node) = P(node transmits)

P(no other node transmits in [t0-1t0]

P(no other node transmits in [t0t0+1]

= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)

hellip choosing optimum p and then letting n

= 1(2e) = 18

even worse than slotted Aloha


CSMA (carrier sense multiple access)

CSMA listen before transmitif channel sensed idle transmit entire

framebull if channel sensed busy defer

transmission

bull human analogy donrsquot interrupt others


CSMA collisions

bull collisions can still occur propagation delay means two nodes may not hear each otherrsquos transmission

bull collision entire packet transmission time wastedndash distance amp

propagation delay play role in in determining collision probability

spatial layout of nodes


CSMACD (collision detection)

CSMACD carrier sensing deferral as in CSMAndash collisions detected within short timendash colliding transmissions aborted reducing channel wastage

bull collision detectionndash easy in wired LANs measure signal strengths compare

transmitted received signalsndash difficult in wireless LANs received signal strength

overwhelmed by local transmission strength

bull human analogy the polite conversationalist





Ethernet CSMACD algorithm

1 NIC receives datagram from network layer creates frame

2 If NIC senses channel idle starts frame transmission If NIC senses channel busy waits until channel idle then transmits

3 If NIC transmits entire frame without detecting another transmission NIC is done with frame

4 If NIC detects another transmission while transmitting aborts and sends jam signal

5 After aborting NIC enters binary (exponential) backoff ndash after mth collision NIC

chooses K at random from 012 hellip 2m-1 NIC waits K512 bit times returns to Step 2

ndash longer backoff interval with more collisions


CSMACD efficiency

bull Tprop = max prop delay between 2 nodes in LANbull ttrans = time to transmit max-size frame

bull efficiency goes to 1 ndash as tprop goes to 0ndash as ttrans goes to infinity

bull better performance than ALOHA and simple cheap decentralized

transprop ttefficiency

511

+=


ldquoTaking turnsrdquo MAC protocols

channel partitioning MAC protocolssect share channel efficiently and fairly at high loadsect inefficient at low load delay in channel access 1N bandwidth

allocated even if only 1 active node

random access MAC protocolssect efficient at low load single node can fully utilize channelsect high load collision overhead

ldquotaking turnsrdquo protocolslook for best of both worlds


pollingbull master node ldquoinvitesrdquo

slave nodes to transmit in turn

bull typically used with ldquodumbrdquo slave devices

bull concernsndash polling overhead ndash latencyndash single point of

failure (master)

master

slaves

poll

data

data



token passingsect control token passed from

one node to next sequentially

sect token messagesect concerns

sect token overhead sect latencysect single point of failure

(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP

cable modemtermination system

sect multiple 40Mbps downstream (broadcast) channelssect single CMTS transmits into channels

sect multiple 30 Mbps upstream channelssect multiple access all users contend for certain upstream

channel time slots (others assigned)

Cable access network

cablemodemsplitter

hellip

hellip

Internet frames TV channels control transmitted downstream at different frequencies

upstream Internet frames TV control transmitted upstream at different frequencies in time slots


DOCSIS data over cable service interface spec sect FDM over upstream downstream frequency channelssect TDM upstream some slots assigned some have contention

bull downstream MAP frame assigns upstream slotsbull request for upstream slots (and data) transmitted

random access (binary backoff) in selected slots

MAP frame forInterval [t1 t2]

Residences with cable modems

Downstream channel i

Upstream channel j

t1 t2

Assigned minislots containing cable modemupstream data frames

Minislots containing minislots request frames

cable headend

CMTS



Summary of MAC protocols

bull channel partitioning by time frequency or codendash Time Division Frequency Division

bull random access (dynamic) ndash ALOHA S-ALOHA CSMA CSMACDndash carrier sensing easy in some technologies (wire) hard

in others (wireless)ndash CSMACD used in Ethernetndash CSMACA used in 80211

bull taking turnsndash polling from central site token passingndash Bluetooth FDDI token ring


MAC addresses and ARP

bull 32-bit IP address ndash network-layer address for interfacendash used for layer 3 (network layer) forwarding

bull MAC (or LAN or physical or Ethernet) addressndash function used lsquolocallyrdquo to get frame from one interface to

another physically-connected interface (same network in IP-addressing sense)

ndash 48 bit MAC address (for most LANs) burned in NIC ROM also sometimes software settable

ndash eg 1A-2F-BB-76-09-AD

hexadecimal (base 16) notation(each ldquonumeralrdquo represents 4 bits)


LAN addresses and ARP

each adapter on LAN has unique LAN address

adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN(wired orwireless)


LAN addresses (more)

bull MAC address allocation administered by IEEEbull manufacturer buys portion of MAC address space (to

assure uniqueness)bull analogy

ndash MAC address like Social Security Numberndash IP address like postal address

bull MAC flat address portability ndash can move LAN card from one LAN to another

bull IP hierarchical address not portablendash address depends on IP subnet to which node is attached


ARP address resolution protocol

ARP table each IP node (host router) on LAN has table

ndash IPMAC address mappings for some LAN nodes

lt IP address MAC address TTLgt

ndash TTL (Time To Live) time after which address mapping will be forgotten (typically 20 min)

Question how to determineinterfacersquos MAC address knowing its IP address

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788


ARP protocol same LAN

bull A wants to send datagram to Bndash Brsquos MAC address not in Arsquos

ARP tablebull A broadcasts ARP query

packet containing Bs IP address ndash destination MAC address =

FF-FF-FF-FF-FF-FFndash all nodes on LAN receive

ARP query bull B receives ARP packet replies

to A with its (Bs) MAC addressndash frame sent to Arsquos MAC

address (unicast)

bull A caches (saves) IP-to-MAC address pair in its ARP table until information becomes old (times out)

ndash soft state information that times out (goes away) unless refreshed

bull ARP is ldquoplug-and-playrdquondash nodes create their ARP

tables without intervention from net administrator


walkthrough send datagram from A to B via Rsect focus on addressing ndash at IP (datagram) and MAC layer (frame)sect assume A knows Brsquos IP addresssect assume A knows IP address of first hop router R (how)sect assume A knows Rrsquos MAC address (how)

Addressing routing to another LAN

R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222

sect A creates IP datagram with IP source A destination B sect A creates link-layer frame with Rs MAC address as destination address

frame contains A-to-B IP datagram

MAC src 74-29-9C-E8-FF-55MAC dest E6-E9-00-17-BB-4B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

sect frame sent from A to R

IPEthPhy

sect frame received at R datagram removed passed up to IP


IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222

sect R forwards datagram with IP source A destination B sect R creates link-layer frame with Bs MAC address as destination address


MAC src 1A-23-F9-CD-06-9BMAC dest 49-BD-D2-C7-56-2A

IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B

Addressing routing to another LANsect R forwards datagram with IP source A destination B sect R creates link-layer frame with Bs MAC address as destination address


IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B

Addressing routing to another LANsect R forwards datagram with IP source A destination B sect R creates link-layer frame with Bs MAC address as dest frame contains

A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy

6-47Link Layer and LANs Check out the online interactive exercises for more examples httpgaiacsumassedukurose_rossinteractive

Ethernet

ldquodominantrdquo wired LAN technology bull single chip multiple speeds (eg Broadcom BCM5761)bull first widely used LAN technologybull simpler cheapbull kept up with speed race 10 Mbps ndash 10 Gbps

Metcalfersquos Ethernet sketch6-48Link Layer and LANs

Ethernet physical topologybull bus popular through mid 90s

ndash all nodes in same collision domain (can collide with each other)

bull star prevails todayndash active switch in centerndash each ldquospokerdquo runs a (separate) Ethernet protocol (nodes

do not collide with each other)

switch

bus coaxial cablestar


Ethernet frame structure

sending adapter encapsulates IP datagram (or other network layer protocol packet) in Ethernet frame

preamble bull 7 bytes with pattern 10101010 followed by one

byte with pattern 10101011bull used to synchronize receiver sender clock rates

destaddress

sourceaddress

data (payload) CRCpreamble

type


Ethernet frame structure (more)bull addresses 6 byte source destination MAC addresses

ndash if adapter receives frame with matching destination address or with broadcast address (eg ARP packet) it passes data in frame to network layer protocol

ndash otherwise adapter discards framebull type indicates higher layer protocol (mostly IP but

others possible eg Novell IPX AppleTalk)bull CRC cyclic redundancy check at receiver

ndash error detected frame is dropped

destaddress

sourceaddress


type


Ethernet unreliable connectionless

bull connectionless no handshaking between sending and receiving NICs

bull unreliable receiving NIC doesnt send acks or nacks to sending NICndash data in dropped frames recovered only if initial

sender uses higher layer rdt (eg TCP) otherwise dropped data lost

bull Ethernetrsquos MAC protocol unslotted CSMACD with binary backoff


8023 Ethernet standards link amp physical layers

bull many different Ethernet standardsndash common MAC protocol and frame formatndash different speeds 2 Mbps 10 Mbps 100 Mbps 1Gbps 10

Gbps 40 Gbpsndash different physical layer media fiber cable

applicationtransportnetwork

linkphysical

MAC protocoland frame format

100BASE-TX

100BASE-T4

100BASE-FX100BASE-T2

100BASE-SX 100BASE-BX

fiber physical layercopper (twisterpair) physical layer


Ethernet switch

bull link-layer device takes an active rolendash store forward Ethernet framesndash examine incoming framersquos MAC address

selectively forward frame to one-or-more outgoing links when frame is to be forwarded on segment uses CSMACD to access segment

bull transparentndash hosts are unaware of presence of switches

bull plug-and-play self-learningndash switches do not need to be configured


Switch multiple simultaneous transmissions

bull hosts have dedicated direct connection to switch

bull switches buffer packetsbull Ethernet protocol used on each

incoming link but no collisions full duplexndash each link is its own collision

domainbull switching A-to-Arsquo and B-to-Brsquo

can transmit simultaneously without collisions switch with six interfaces

(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Switch forwarding table

Q how does switch know Arsquoreachable via interface 4 Brsquoreachable via interface 5

switch with six interfaces(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6sect A each switch has a switch table each entrysect (MAC address of host interface

to reach host time stamp)sect looks like a routing table

Q how are entries created maintained in switch table

sect something like a routing protocol


A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6

Switch self-learning

bull switch learns which hosts can be reached through which interfaces

ndash when frame received switch ldquolearnsrdquo location of sender incoming LAN segment

ndash records senderlocation pair in switch table

A Arsquo

Source ADest Arsquo

MAC addr interface TTLSwitch table

(initially empty)A 1 60


Switch frame filteringforwarding

when frame received at switch

1 record incoming link MAC address of sending host2 index switch table using MAC destination address3 if entry found for destination

then if destination on segment from which frame arrived

then drop frameelse forward frame on interface indicated by entry

else flood forward on all interfaces except arriving

interface 6-58Link Layer and LANs

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6

Self-learning forwarding exampleA Arsquo

Source ADest Arsquo

MAC addr interface TTLswitch table


A ArsquoA ArsquoA ArsquoA ArsquoA Arsquo

bull frame destination Arsquo location unknown flood

Arsquo A

sect destination A location known

Arsquo 4 60

selectively send on just one link


Interconnecting switches

self-learning switches can be connected together

Q sending from A to G ndash how does S1 know to forward frame destined to G via S4 and S3sect A self learning (works exactly the same as in

single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G


Self-learning multi-switch exampleSuppose C sends frame to I I responds to C

sect Q show switch tables and packet forwarding in S1 S2 S3 S4

A

B

S1

C D

E

FS2

S4

S3

HI

G


Institutional network

to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers

both are store-and-forward sect routers network-layer

devices (examine network-layer headers)

sect switches link-layer devices (examine link-layer headers)

both have forwarding tablessect routers compute tables using

routing algorithms IP addresses

sect switches learn forwarding table using flooding learning MAC addresses


linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


Link layer introduction

terminologybull hosts and routers nodesbull communication channels that

connect adjacent nodes along communication path linksndash wired linksndash wireless linksndash LANs

bull layer-2 packet frameencapsulates datagram

data-link layer has responsibility of transferring datagram from one node to physically adjacent node over a link


Link layer context










algorithm


Link layer services











retransmission


at same time







software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


linkphysical











datagram datagram

datagram

frame


Error detection



otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


Link layer context










algorithm


Link layer services











retransmission


at same time







software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


linkphysical











datagram datagram

datagram

frame


Error detection



otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


Link layer services











retransmission


at same time







software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


linkphysical











datagram datagram

datagram

frame


Error detection



otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram






retransmission


at same time







software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


linkphysical











datagram datagram

datagram

frame


Error detection



otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram






software firmware

controller


cpu memory

host bus (eg PCI)

network adaptercard


linkphysical











datagram datagram

datagram

frame


Error detection



otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram











datagram datagram

datagram

frame


Error detection



otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


Error detection



otherwise


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


Parity checking


errors


0 0



















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


















CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram







CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


CRC example

wantD2r XOR R = nG



R = remainder[ ]D2r

G
























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram























4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram














4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram







4 simple







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram







turns





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram





send slots 256 idle

1 3 4 1 3 4

6-slotframe

6-slotframe



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram



bands 256 idle

frequ

ency

ban

ds

time

FDM cable










Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram









Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


Slotted ALOHA














bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram





bull simple





2

3

2 2

3 3

node 1

node 2

node 3

C C CS S SE E E




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram




















= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram











= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram






= p (1-p)N-1 (1-p)N-1

= p (1-p)2(N-1)


= 1(2e) = 18






transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram





transmission



CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


CSMA collisions

























CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram





















CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram














CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram











CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


CSMACD efficiency





511

+=












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram












failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram






failure (master)

master

slaves

poll

data

data







(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram






(token)

T

data

(nothingto send)

T



cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


cable headend

CMTS

ISP






cablemodemsplitter

hellip

hellip










Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram








Upstream channel j

t1 t2



cable headend

CMTS



















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


















adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram












adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram




adapter

1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53
















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram















1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram








1A-2F-BB-76-09-AD

58-23-D7-FA-20-B0

0C-C4-11-6F-E3-98

71-65-F7-2B-08-53

LAN

137196723

137196778

137196714

137196788









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram









address (unicast)








R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram




R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy

IP src 111111111111IP dest 222222222222





R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

B

Brsquo C

Crsquo

1 2

345






A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A Arsquo

Source ADest Arsquo











A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6


Source ADest Arsquo





Arsquo A


Arsquo 4 60






single-switch case)

A

B

S1

C D

E

FS2

S4

S3

HI

G




A

B

S1

C D

E

FS2

S4

S3

HI

G



to externalnetwork

router

IP subnet

mail server

web server


Switches vs routers








linkphysical

networklink

physical

linkphysical

switch

datagram


linkphysical

frameframe

framedatagram


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IPEthPhy


IPEthPhy



IP src 111111111111IP dest 222222222222

IP src 111111111111IP dest 222222222222


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


IP src 111111111111IP dest 222222222222




IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B



IP src 111111111111IP dest 222222222222


IPEthPhy

IPEthPhy


R

1A-23-F9-CD-06-9B222222222220

111111111110E6-E9-00-17-BB-4BCC-49-DE-D0-AB-7D

111111111112

11111111111174-29-9C-E8-FF-55

A

22222222222249-BD-D2-C7-56-2A

22222222222188-B2-2F-54-1A-0F

B


A-to-B IP datagram

IP src 111111111111IP dest 222222222222


IPEthPhy


Ethernet







switch







destaddress

sourceaddress


type







destaddress

sourceaddress


type












linkphysical


100BASE-TX

100BASE-T4





Ethernet switch












(123456)

A

Arsquo

B

Brsquo C

Crsquo

1 2

345

6





A

Arsquo

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linkphysical

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Documents

Chapter 6: Link Layer and LANs