InternetworkingBy. Ozmar AzhariCSCO11167205

Jan - 11

INTERNETWORKING SCHEME

OSI REFERENCE MODELCreated by ISO year of 1977Framework for creating and

implementing networking standards, devices, and internetworking schemes

To assist data transfer between disparate hosts (different vendors)

Divided into Upper and Lower Layer

LAYER FUNCTION

TRANSPORT LAYERSegments and reassembles data into data stream

to provide end to end data transport services and establish a logical connection between source and destination

Well known protocol in this layer is TCP and UDPTwo types of transport layer is connection

oriented and connection lessPDU: Segment

CONNECTION ORIENTEDProvide reliable connection between hostsUse 3-way handshake to establish sessionThere are flow control, windowing, and

acknowledge to better provide the connectionTCP is the sample of connection oriented

protocol

NETWORK LAYERNetwork layer provide device addressing, tracking of device

location in the network, determines best path to move data.IP Address is the well-known network layer logical

addressingTwo types of packets at network layer:

Data packet (IP, IPX, Novell, AppleTalk) usually called Routed Protocol

Route update packet (RIP, EIGRP, OSPF, ISIS, BGP) usually called Routing Protocol

PDU: Packet

DATA LINK LAYERProvide physical transmission of the data and

handles error detection and flow control.This layer will ensure messages are delivered to

the proper device on LAN using hardware addressTwo pars of Data Link are:

LLCMAC

PDU: Frame

PHYSICAL LAYER

Specify electrical, mechanical, procedural,

and functional requirements for activating,

maintaining, and deactivating a physical link

between end systems.

PDU: Byte/Bits

TCP/IP DOD STACKDoD model is the condensed version of the OSI

Model, composed of four layers:Process/Application LayerHost-to-Host LayerInternet LayerNetwork Access layer

Worldwide internet is built based on this DoD Stack

DATA ENCAPSULATIONData to be delivered through network will be encapsulated as the data goes down the layer:1. User information is converted to data for transmission on the

network2. Data is converted into segments and a reliable connection is

establish between source and destination hosts3. Segments are converted to packets, and logical address is placed in

the header so each packet can be routed through an internetwork4. Packets are converted to frames for transmission on the network.

Hardware address are used to uniquely identify host on local network segments

5. Frame are converted into bits, and digital encoding and clocking scheme are used.

INTERNETWORKING COMPONENT

• Hub

• Switch

• Router

HUBDevice for connecting multiple devices

(usually computer) together and making them act as a single network segment

Works at OSI Layer 1Obsolete and not recommended to be used in

large networkDumb Terminal and only broadcast every

packet its received

SWITCHCentral part of LAN NetworkIntelligent device with switching capabilityStored switching information in CAM TableNot able to break broadcast domain (except

using VLAN)Do not forward packet to other networkWork at OSI Layer 2

ROUTERUse to connect networks together and router

packets from one network to another Break broadcast domainUse routing protocol to build routing table to

make path selectionWorks in OSI Layer 3

COLLISION & BROADCAST DOMAINCollision domain is a scenario where in only

one particular device can send a packet on a network segment, if there are two devices send packets in the same time there will be a collision

Broadcast domain is a domain where a broadcast packet will be send to every devices sit in the same domain

COLLISION & BROADCAST DOMAINHub has 1 collision domain and 1 broadcast

domainSwitch have many collision domain (depends

on number of ports) and 1 Broadcast domainRouter have many collision domain (depends

on number of ports) and many broadcast domain (depends on number of ports)

INTRODUCTION TO ETHERNETIs a contention media access method that

allows all host on a network to share the same bandwith of a link, usually called broadcast media.

Has a collision prevention method called Carrier Sense Multiple Access with Collision Detection (CSMA/CD).

HALF AND FULL-DUPLEX ETHERNET Ethernet can have two mode of operation:

Half-duplex Uses only one wire pair with a digital signal running in both

directions of the wire Hub must use half-duplex so that end user is able to detect

collision Bandwidth can not be use to the maximum, usually only 30-40% of

the link bandwidth

Full-duplexUses two pairs of wires instead of one pair.No collisions will occurFaster data transfer rate (eg. 10Mbps link will get 20Mbps rate)

ETHERNET CABLINGTypes of ethernet cabling are:

Straight-Through CablingCrossover cablingRolled over Cabling

STRAIGHT-THROUGH CABLINGUse to Connect:

Host to Switch or HubRouter to Switch or hub

CROSS OVER CABLINGUse to Connect

Switch to SwitchHub to HubHost to HostHub To Switch Router to host

ROLLED OVER CABLINGUse to connect to router or switch for

management purposes

OPTICAL ETHERNETDivided into two type:

Multimode (MMF)Wavelength: 850nmDistance: up to 550mNickname : S or SX (usually being called “short”)

Singlemode (SMF)Wavelength: 1310-1550nmDistance: 10km (1310nm) up to 70km (1550nm)Code: L/LX/LH for 1310nm (usually called “long”)and Z/ZX for1550nm (usually called “extended long”)

REVIEW QUESTIONSAt which layer is routing occurs in TCP/IP stack?Which OSI layer can determine the availability of

the receiving program and check whether there are enough resources for that communication?

What Is CSMA/CD?Different between Half and Full Duplex?

Oct-10

THANK YOU