Clase Nº4 -...

Jorge Sa Silva

sasilva@dei.uc.pt

University of Coimbra

Portugal

Clase Nº4

2

Outline

• Multicast

• Future Internet

• IPv6

• QoS

• Mobile IP

3

4

IGMP

Routing Protocols

Router

Router

Router

Router

Router

Router

Router

Router

Router

RouterRouter

5

Ethernet

Wireless or satellites (broadcast)

6

Addresses

IGMP

Routing algorithms

Present solutions - protocols

Source Specific Multicast (SSM)

7

0 netid hostid

1 0 netid hostid

1 1 0 netid hostid

1 1 1 0 multicast address

1 1 1 1 uso futuro

0 1 8 16 24 32

Classe A

Classe B

Classe C

Classe D

Classe E

8

Internet Group Message Protocol

Router

Router

Router

Router

Router

Router

Router

Router

Router

RouterRouter

9

Flooding

Spanning Trees

Reverse –Path Forwarding

RPF e Prunes

Steiner Trees

Center-Based Trees

10

◦ To route the data only to multicast members;

◦ Optimized routes from the sources to destinations;

◦ No loops;

◦ Distributed routes;

◦ Support dynamic members.

11

Easy to implement

Simple

Use of resources

12

B

C

A

D

F

E

3

3

7

1

4

1

5

13

B

C

A

D

F

E

3

3

7

1

4

1

5

B

C

A

D

F

E

1

5

6

2

4

3

7

B

C

A

D

F

E

1

5

6

2

4

3

7

14

Prune messages

Algorithm

Periodic messages

Dynamic groups

15

Prune messages

Graft messages

Dynamic groups

16

B

C

A

D

F

E

1

5

6

2

4

3

7

B

C

A

D

F

E

1

5

6

2

4

3

7

17

Tree with a central node

Join and leave messages (IGMP)

Less information

Unidirectional and bi-directional trees

Problem: centre !

18

Dense-mode

Sparse-mode

19

Distance-vector

RPF

Tunnels

20

Ethernet

A B

C

Ethernet

Ethernet

A B

C

D

RPF, prune and graft

21

B

C

A

D

F

E

1

5

6

2

4

3

7B

C

A

D

F

E

1

5

6

2

4

3

7

CBT

22

PIM-SM

Multicast Source Discovery Protocol

Multicast Border Gateway Protocol

23

Different ISPs

Compatibility of internal routing protocols

Address allocation

24

IGMPv3

MLDv2

Allowed sources

Advantages

25

26

8 4 4 112

11111111 Flags Scope Group ID

• Number of multicast addresses

• Multicast-Ready

• Address allocation

27

Ordered transmission and without errors

TCP vs UDP

Reliable Muticast ◦ Unreliable

◦ Semireliable

◦ Reliable

28

Statistically reliable (%)

K-reliable

Sufficiently reliable (timeouts)

29

Source ordering

Total ordering

30

It is necessary to maintain a list for all receivers that already received ACKs.

Only after receiving all ACKs (from all receivers) to a specific data block, the source will delete that block in memory.

ACKs explosion

31

The source can implement timeout mechanisms

The performance of source-initiated protocols are dependent of the number of participants.

A multicast group with a large number of members implies a large number of positive ACKs, and a large number of NACKs in instable environments,

32

When a receiver detects that it doesn’t receive a packet, it must wait a random period and sends a NACK to the source and to all receivers.

This procedure reduces the number of NACKs in the system.

This procedure can only be applied in small networks (where the number of participants is low).

33

Tree Ring These protocols require less memory, the

source doesn’t need to be aware of all receivers and the system is not dependent of the number of participants.

34

The missing information is recovered by redundant information.

35

Fragmentation/desfragmentation

Address/Routing

36

32 bits

Networks ID

Host ID

Routing

37

Dotted-decimal notation

Ex: 193.212.12.21

38

Routing and management

Subnetting – Sub-network management

Ex: 223.1.1.0/24

39

1)

IP address: 138.251.26.12

Subnet Mask: 255.255.255.0

Binary: 10001010.11111011.00011010.00001100

11111111.11111111.11111111.00000000

2)

IP address: 199.124.16.137

Subnet Mask: 255.255.255.192

Binary: 11000111.01111100.00010000.10001001

11111111.11111111.11111111.11000000

(Network 199.128.16.128, terminal 9)

40

Binary Decimal

11111111.11111111.11111111.00000000 255.255.255.0

11111111.11111111.11111111.10000000 255.255.255.128

11111111.11111111.11111111.11000000 255.255.255.192

11111111.11111111.11111111.11100000 255.255.255.224

11111111.11111111.11111111.11110000 255.255.255.240

11111111.11111111.11111111.11111000 255.255.255.248

11111111.11111111.11111111.11111100 255.255.255.252

11111111.11111111.11111111.11111110 255.255.255.254

41

0 netid hostid

1 0 netid hostid

1 1 0 netid hostid

1 1 1 0 multicast address

1 1 1 1 uso futuro

0 1 8 16 24 32

Classe A

Classe B

Classe C

Classe D

Classe E

42

50 0 0 0 1 2 3 4 5 6 7 8 9

Numero do primeiro elemento

Identificador do Pacote

Mais fragmentos

50 0 1 0 1 2 3 4 5 6 7

Numero do primeiro elemento

Identificador do Pacote

Mais fragmentos

50 8 0 8 9

Numero do primeiro elemento

Identificador do Pacote

Mais fragmentos

43

Source IP address

Header checksum

TOSVersion IHL

Time to live Protocol

Identification Fragment offset

Total length

Flags

Destination IP address

Options Padding

User data

20 bytes

4-40

bytes

32 bits

44

VER (4 bits) ◦ Version (version 4)

IHL (4 bits) ◦ Internet Header Length – units of 4 bytes. By

default it is 5 (20 bytes). ◦ This is necessary as the header length is not

constant (options).

ToS (8bits) ◦ Type of Service

TL (16 bits) ◦ Total Length – datagram length (bytes),

header+data

45

ID (16 bits) ◦ Identify the datagrams from the same segment.

Flag (3 bits) ◦ ―Don’t fragment‖ ◦ ―More fragments‖

FO (3 bits) ◦ Fragment position in the original datagram (unities of 8

bytes)

TTL (8 bits) ◦ Time To Live .

PROT (8 bits) ◦ Protocol

Header Checksum (16 bits)

46

47

Rede

10.0.0.0Router A

Rede

20.0.0.0Router B

Rede

30.0.0.0Router C

Rede

40.0.0.0

10.0.0.5 20.0.0.5 20.0.0.6 30.0.0.6 30.0.0.7 40.0.0.7

Router B

Estação na rede Encaminhamento

20.0.0.0 Directo

30.0.0.0 Directo

10.0.0.0 20.0.0.5

40.0.0.0 30.0.0.7

48

Address allocation poorly managed at the beginning

Solutions ◦ Address re-distribution (?)

◦ IPv6

◦ NAT

49

Mapping of public addresses – private addresses ◦ 10.0.0.0 a 10.255.255.255 (1 network of

class A) ◦ 172.16.0.0 a 172.31.255.255 (16 networks

of class B) ◦ 192.168.0.0 a 192.168.255.255 (255

networks of class C)

NAT (using ports) ◦ Static ◦ Dynamic ◦ Overloading ◦ DHCP

Security support

Rede

Privada

Internet

50

IANA – Internet Assigned Numbers Authority

Public addresses

Private addresses

NAT (Network Adress Translation)

51

Adresses

Routing

Anycast

Auto-configuration

Multicasting

QoS support

Security

52

Source IP address

Version

Next Header Hop limitPayload length

Flow label

40 bytes

32 bits

Traffic class

Destination IP address

Base HeaderExtension

Header 1

Extension

Header nData...

53

Hop by Hop Options Header

Destination Options Header

Routing Header

Fragment Header

Authentication Header

Encapsulation Security Payload Header

IPv6 HeaderNext Header =

Routing

Routing

Header

Next Header =

TCPTCP Header Data

54

v4: 196.132.204.12

v6:

196.132.204.12.196.132.204.12.196.132.204.12.196.132.204.12

fce0:a3c2:0000:2020:aa63:43a4:0000:a1a1

55

TLA - Top-Level Aggregation Identifier RES - Reserved for future use NLA - Next-Level Aggregation Identifier SLA - Site-Level Aggregation Identifier Interface ID - Interface Identifier

Unicast

Multicast

56

First bits Representation Type of address

00…0 (128 bits) ::/128 Não especificado

00…1 (128 bits) ::1/128 Endereço loop-back

11111111 FF00::/8 Endereços multicast

1111111010 FE80::/10 Endereços link-local

1111111011 FEC0::/10 Endereços site-local

restantes Endereços globais unicast

57

Rede IPv 6

Rede IPv 6

Router

Router

IPv 4

IPv 4

IPv 4

IPv 4

58

Data (e-mail, FTP, Telnet, WWW)

Audio (Voice over IP, Hi-fi)

Video (HDTV, VoD, videoconferencing)

Distributed processing (CAD, simulations)

Other (virtual reality, tele-medicine)

Applications

59

What is it? ◦ Different levels of service for different types of

traffic Relevant parameters

Throughput

Delay

Jitter

Loss

◦ Fairness Competing traffic flows

Provide level of service according to SLAs

IP Quality of Service

60

Isn't over-provisioning enough to solve IP QoS problems?

◦ Network resources (e.g., bandwidth) are not infinite

◦ Existing network resources are a trade-off between

cost/investment and performance

◦ There is the need to guarantee the agreed service level to applications, even when resources are not enough QoS is also a business opportunity

The need for quality of service

61

How to guarantee that a network initially engineered for the support of elastic traffic (the Internet) can properly carry inelastic traffic?

The only networking technology designed from scratch for the

support of all types of traffic is ATM

How to guarantee that applications with different needs

get the resources they need (and that have paid for) even under global resource shortage?

How to guarantee fairness among different traffic flows?

IP QoS provision problems

62

Throughput Peak rate

Mean rate

Delay Maximum delay

Delay variation (jitter, delay jitter)

Losses Due to congestion

Error rate

Needs of applications

63

ITU-T Rec. G.114 defines three categories of applications in terms of end-to-end delay

Delay < 150 ms — acceptable delay for most applications

150 < delay < 400 ms — significant delay for some applications

Delay > 400 ms — unacceptable delay for most applications (namely telephony and conferencing)

Transit delay

64

Acceptable loss/error rates

10-4 , for voice applications and file transfer applications

10-6 , for interactive data applications

10-7 , for image transfer applications

10-8 , for interactive compressed image transfer applications

Loss/Error rate

65

Throughput

(Mbps)

De

lay

(ms

)

0.01 0.1 1 10 100 1000

1

10

100

1000

VoiceAudio

Hi-Fi

VoD/

Moving

images

HDTVVirtual

reality

Interactive

dataStill images

Intensive

data

Mainframe

interconn.

E-mailFile

transfer

Delay and throughput needs

66

Data Network

Best-effort paradigm

New paradigms ◦ Integrated Services

◦ Differentiated Services

67

Routers

Resource procedures

Individual and group flows

68

Guaranteed Services (GS)

Controlled Load Services (CLS)

69

Unicast / Multicast

IPv4 / IPv6

Soft-State

70

Type of Service

Per Hop Behaviour (PHBs)

Service Level Agreement (SLAs)

71

Router

Router

Router

Router

Router

Router

Router

Router

Router

72

Layer 2

Layer 3

73

HA

FA

Permanent address

Care-of-address

Foreign

Agent Home

Agent

Corresponding

node

Corresponding

Agent

Mobile

Node

1

2

3

74

Overcome the triangle routing problem

But adds complexity ◦ Learn the new COA ◦ Notify protocol to

the alert the CN ◦ Anchor foreign

agent

Foreign

Agent Home

Agent

Corresponding

node

Corresponding

Agent

Mobile

Node

1

2

3

4

75

Organisations rely more and more on information processing

Networking plays a vital role in (distributed) information processing

There is a growing demand for bandwidth ◦ Increasing utilisation ◦ Many applications rely on high bandwidth consumption ◦ Information systems heavily rely on networking

IP networking is ubiquitous ◦ If applications are carried over IP they will also be

ubiquitous

IP Networking

76

FA HA

CN

MN

Rede

Hospedeira

Rede

Base

Cabeçalho

OriginalNovo Cabeçalho

Pacote IP original

Source=HA

Dest=COASource)CN

Dest=MN

77

Discovery Protocol

Registration Procedure

Encapsulation Procedure

78

Sequence numbers

Life-Time

Flags

COAs

79

Basic (RFC 2003)

Minimum (RFC2004)

Generic Routing Encapsulation (RFC 1701)

80

128 bits addresses

Autoconfiguration ◦ Plug and Play

Low process in routers ◦ Path MTU Discovery

◦ Reduced routing tables

◦ Simplified headers

81

v4: 196.132.204.12

v6:

196.132.204.12.196.132.204.12.196.132.204.12.196.132.204.12

fce0:a3c2:0000:2020:aa63:43a4:0000:a1a1

82

Nodes mobile-ready

Redirects

There in no FA