Avaya Configuring IP Multicasting and Multimedia Services Instrukcja Użytkownika Pobierz pdf (Strona 155)

Configuring IGMP Relay

303527-A Rev. 00

9-5

In addition to soliciting multicast group membership information from directly

attached networks, the IGMP-R device relays multicast data packets generated by

downstream hosts to the upstream MOSPF boundary router or the appropriate

upstream interface. IGMP-R also receives multicast data packets from the

upstream router and forwards them to the appropriate group members.

In Figure 9-3

, for example, the following events occur:

1. Host 1 generates a datagram addressed to a multicast group and sends it

upstream to the IGMP-R device.

2. IGMP-R forwards the multicast datagram upstream to the MOSPF boundary

router. IGMP-R also forwards the packet on a downstream interface to a local

group member.

3. The MOSPF boundary router sends the datagram out the appropriate interface

or interfaces to remote group members.

Figure 9-3. IGMP-R and Upstream Multicast Data

A downstream host can also send an unsolicited join message to the IGMP-R

device. IGMP-R forwards the message upstream to the MOSPF boundary router.

IP0073A

IGMP Relay

MOSPF

AS boundary

router

LAN A

LAN B

LAN C

Host 1

Local

group

member

Remote

group

member

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Avaya Configuring IP Multicasting and Multimedia Services Instrukcja Użytkownika Strona 155