3Com Switch 7750 Configuration Guide Guide

386 CHAPTER 40: IGMP SNOOPING CONFIGURATION
Figure 91 Multicast packet transmission with or without IGMP Snooping being enabled
IGMP Snooping
Implementation
IGMP Snooping terminologies
■ Router port: the switch port directly connected to the multicast router.
■ Multicast member port: a switch port connected to a multicast group member
(a host in a multicast group).
■ MAC multicast group: a multicast group identified by a MAC multicast address
and maintained by the switch.
■ Router port aging timer, multicast member port aging timer, and query
response timer are described in
Table 304.
Layer 2 multicast with IGMP Snooping
The switch runs IGMP Snooping to listen to IGMP messages and map the host, the
port corresponding to the host, and the corresponding multicast MAC address.
Internet
Video stream
VOD server
Layer 2 Ethernet sw itch
Muliticast router
Video stream
Video stream
Video stream
Multicas t
group member
Non-multicast
group member
Non-multicas t
group member
Video stream
Video stream
Inter net
Video stream
VOD server
Layer 2 Ethernet sw itch
Muliticast router
Video stream
Multicas t
gr oup me mb e r
Non -multic as t
gr oup me mb e r
Non-multicas t
gr oup me mb e r
Video streamVideo stream
Multicast packet transmission
without IGMP Snooping
Multicast packet transmission
with IGMP Snooping
Internet
Video stream
Muliticast
Multicas t
group member
Non-
group member
Non-
group member
Inter net
Video stream
Muliticast
Multicas t
gr oup me mb e r
Non -
gr oup me mb e r
Non-
gr oup me mb e r
Multicast packet transmission
without IGMP Snooping
Internet
Video stream
VOD server
Layer 2 Ethernet sw itch
Muliticast router
Video stream
Video stream
Video stream
Multicas t
group member
Non-
group member
Non-
group member
Video stream
Video stream
Inter net
Video stream
VOD server
Layer 2 Ethernet sw itch
Muliticast router
Video stream
Multicas t
gr oup me mb e r
Non -
gr oup me mb e r
Non-
gr oup me mb e r
Video streamVideo stream
Multicast packet transmission
without IGMP Snooping
Multicast packet transmission
with IGMP Snooping
Internet
Video stream
Muliticast
Multicas t
group member
Non-
group member
Non-
group member
Inter net
Video stream
Muliticast
Multicas t
gr oup me mb e r
Non -
gr oup me mb e r
Non-
gr oup me mb e r
Multicast packet transmission
without IGMP Snooping
Internet
Video stream
VOD server
Layer 2 Ethernet sw itch
Muliticast router
Video stream
Video stream
Video stream
Multicas t
group member
Non-multicast
group member
Non-multicas t
group member
Video stream
Video stream
Inter net
Video stream
VOD server
Layer 2 Ethernet sw itch
Muliticast router
Video stream
Multicas t
gr oup me mb e r
Non -multic as t
gr oup me mb e r
Non-multicas t
gr oup me mb e r
Video streamVideo stream
Multicast packet transmission
without IGMP Snooping
Multicast packet transmission
with IGMP Snooping
Internet
Video stream
Muliticast
Multicas t
group member
Non-
group member
Non-
group member
Inter net
Video stream
Muliticast
Multicas t
gr oup me mb e r
Non -
gr oup me mb e r
Non-
gr oup me mb e r
Multicast packet transmission
without IGMP Snooping
Internet
Video stream
VOD server
Layer 2 Ethernet sw itch
Muliticast router
Video stream
Video stream
Video stream
Multicas t
group member
Non-
group member
Non-
group member
Video stream
Video stream
Inter net
Video stream
VOD server
Layer 2 Ethernet sw itch
Muliticast router
Video stream
Multicas t
gr oup me mb e r
Non -
gr oup me mb e r
Non-
gr oup me mb e r
Video streamVideo stream
Multicast packet transmission
without IGMP Snooping
Multicast packet transmission
with IGMP Snooping
Internet
Video stream
Muliticast
Multicas t
group member
Non-
group member
Non-
group member
Inter net
Video stream
Muliticast
Multicas t
gr oup me mb e r
Non -
gr oup me mb e r
Non-
gr oup me mb e r
Multicast packet transmission
without IGMP Snooping
Tabl e 304 IGMP Snooping timers
Timer Setting
Packet normally
received before
timeout
Timeout action on
the switch
Router port aging
timer
Aging time of the
router port
IGMP general query
message/PIM
message/DVMRP
probe message
Consider that this
port is not a router
port any more.
Multicast member
port aging timer
Aging time of the
multicast member
ports
IGMP message
Send an IGMP
group-specific query
message to the
multicast member
port.
Query response timer
Query response
timeout time
IGMP report message
Remove the port from
the member port list
of the multicast
group.