3com 2928 Betriebsanweisung

 

1-2 

IGMP snooping related ports 

Router A

Switch A

Switch B

GE1/0/1

GE1/0/2

GE1/0/3

GE1/0/1

GE1/0/2

Host A

Host B

Host C

Host D

 Multicast packets

Router port

Member port

 

 
IGMP snooping related ports include: 

z

 

Router port: A router port is a port on an Ethernet switch that leads the switch towards the Layer 3 
multicast device (DR or IGMP querier). In the figure, GigabitEthernet 1/0/1 of Switch A and 
GigabitEthernet 1/0/1 of Switch B are router ports. A switch registers all its local router ports in its 
router port list.  

z

 

Member port: On an Ethernet switch, a member port (also known as multicast group member port) 
connects the switch to a multicast group member. In the figure, GigabitEthernet 1/0/2 and 
GigabitEthernet 1/0/3 of Switch A and GigabitEthernet 1/0/2 of Switch B are member ports. A 
switch registers all its member ports in the IGMP snooping forwarding table.  

 

z

 

Whenever mentioned in this document, a router port is a port on the switch that leads the switch to 
a Layer 3 multicast device, rather than a port on a router.  

z

 

Unless otherwise specified, router ports and member ports mentioned in this document consist of 
dynamic and static ports. 

z

 

An IGMP-Snooping-enabled switch deems that all its ports on which IGMP general queries with the 
source address other than 0.0.0.0 or PIM hello messages are received to be router ports.  

 

A switch running IGMP snooping performs different actions when it receives different IGMP messages, 
as follows: