Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 1

Lesson 9

Internet Group Management Protocol

(IGMP)

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 2

Internet Group Management Protocol (IGMP)

IP multicasting overview Host and router support for IP

multicasting IGMP version 1 IGMP version 2 IGMP version 3 Windows support for IGMP

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 3

IP Multicasting Overview

One-to-many delivery w/o broadcasting Class D IP multicast addresses

224.0.0.0/4 Address range of 224.0.0.0 to 239.255.255.255 Specific address is a group address

Multicast or host group The set of hosts listening on a specific IP

multicast address

Group can be any size Members located anywhere on the IP

internetwork

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 4

Host Support for IP Multicasting

Sending IP multicast traffic Host determines destination multicast traffic Multicast route(s) in IP routing table ARP not used when sending

Receiving IP multicast traffic Maintain multicast MAC address table entries Send IGMP Host Membership Report message is

sent to inform local routers to forward the host group traffic to the network segment of the listening host

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 5

Router Support for IP Multicasting

Listen for IGMP Host Membership Report messages sent from hosts on local network segments

Track and maintain group membership for hosts on local network segments

Communicate host group membership information to neighboring routers

Listen for all IP multicast traffic on all attached network segments

Forward IP multicast traffic with a valid TTL on appropriate network segments

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 6

Multicast-Enabled IP Internetwork

Multicast routing protocols M

ultic

ast r

outin

g pr

otoc

ols

IGMPHost Membership

Report

IP multicasttraffic

Listeninghost

Sendinghost

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 7

IGMP Message Encapsulation

IP Header IGMP Message

IGMP Message

IP Datagram

NetworkInterfaceHeader

NetworkInterfaceTrailer

Network Interface Layer Frame

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 8

IGMP version 1 (IGMPv1)

Two types of IGMPv1 messages Host Membership Report

Used by a host to report host membership in a specific group

Host Membership Query Used by a router to query host group membership on a

network segment

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 9

IGMPv1 Message Structure

VersionType

UnusedChecksum

Group Address

= 1

Type = 1: Host Membership QueryType = 2: Host Membership Report

= 1 or 2

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 10

IGMP version 2 (IGMPv2)

Changes from IGMPv1 The Leave Group message The Group-Specific Query message The election of a multicast querier New format for the IGMPv2 Host Membership

Report message

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 11

IGMPv2 Message Structure

TypeMaximum Response Time

ChecksumGroup Address

Type = 17: Host Membership QueryType = 22: IGMPv2 Host Membership ReportType = 23: Leave Group Message

= 17, 22, or 23

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 12

IGMP version 3 (IGMPv3)

Supports multicast source-specific reports and queries

IGMPv3 Host Membership Report message can specify: The list of multicast sources from which the

host can receive the multicast packets (the include list)

or The list of the multicast sources from which the

host must not receive multicast packets (the exclude list)

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 13

IGMPv3 Host Membership Query

TypeMaximum Response Time

ChecksumGroup Address

ReservedSupress Router-Side Processing

Querier’s Robustness VariableQuerier's Query Interval

Number of SourcesSource Address 1

. . .

= 0x11

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 14

IGMPv3 Host Membership Report

TypeReserved

ChecksumReserved

Number of Group RecordsGroup Record 1

. . .Group Record N

= 0x22

. . .

. . .

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 15

IGMPv3 Host Membership Report Message Group Record

Record TypeAuxiliary Data Length

Number of SourcesMulticast AddressSource Address 1

Source Address nAuxiliary Data . . .

. . .

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 16

Windows Support for IGMP

TCP/IP Protocol IGMPv3-capable host Mapping of IP multicast addresses for Ethernet,

FDDI, and Token Ring Multicast forwarding based on the entries in the

TCP/IP multicast forwarding table

Routing and Remote Access service Limited multicast forwarder using IGMPv1,

IGMPv2, or IGMPv3 to track local group membership

IGMP routing protocol component Interfaces set for IGMP Router Mode or IGMP Proxy Mode

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 17

IGMP Router Mode and Proxy Mode

IP multicast-enabledinternetwork

Sendingor receiving

host

Windows Server 2003 router

NeighboringIP multicast-enabled

router

IGMP proxy modeinterface

IGMP router modeinterface

Microsoft Windows Server 2003 TCP/IP Protocols and Services Technical Reference Slide: 18

Review

IP multicasting overview Host and router support for IP

multicasting IGMP version 1 IGMP version 2 IGMP version 3 Windows support for IGMP