Basic Concepts In Igmp Snooping - H3C S3100 8C SI Operation Manual

Operation Manual – Multicast
H3C S3100 Series Ethernet Switches

2.1.2 Basic Concepts in IGMP Snooping

I. IGMP Snooping related ports
As shown in
runs on Switch A and Switch B, Host A and Host C are receiver hosts (namely, multicast
group members).
Router A
Source
Figure 2-2 IGMP Snooping related ports
Ports involved in IGMP Snooping, as shown in
Router port: A router port is a port on the Layer 3 multicast device (DR or IGMP
querier) side of the Ethernet switch. In the figure, Ethernet 1/0/1 of Switch A and
Ethernet 1/0/1 of Switch B are router ports. A switch registers all its local router
ports in its router port list.
Member port: A member port is a port on the multicast group member side of the
Ethernet switch. In the figure, Ethernet 1/0/2 and Ethernet 1/0/3 of Switch A and
Ethernet 1/0/2 of Switch B are member ports. The switch records all member ports
on the local device in the IGMP Snooping forwarding table.
II. Port aging timers in IGMP Snooping and related messages and actions
Table 2-1 Port aging timers in IGMP Snooping and related messages and actions
Timer
Router port
aging timer
Figure 2-2, Router A connects to the multicast source, IGMP Snooping
Switch A
Eth1/0/1 Eth1/0/2
Eth1/0/3
Eth1/0/1
Eth1/0/2
Switch B
Router port
Member port
Multicast packets
Description
For each router port, the
switch sets a timer
initialized to the aging
time of the route port
Chapter 2 IGMP Snooping Configuration
Receiver
Host C
Host D
Figure 2-2, are described as follows:
Message
before expiry
IGMP general
query or PIM
hello
2-2
Receiver
Host A
Host B
Action after
expiry
The switch
removes this port
from its router port
list