Allied Telesis AR400 manual Explanation from the perspective of switch 2, the snooper

Query solicitation (rapid recovery from topology changes) > Why convergence takes so long without query solicitation

When link is up

Explanation from the perspective of switch 2, the snooper

When the link is connected (all ports are up), the Snooper has entries for two ports:

zport 9, which is the Snooper’s connection to the client. The Snooper sends the multicast stream out this port, as well as sending Queries (the Snooper floods Queries out all its ports)

zport 1, which is the Snooper’s connection to the Querier. This is an All Groups entry, so the Snooper forwards Reports out this port.

The output of the command show igmpsnooping shows both entries.

Manager Switch 2> show igmpsnooping

IGMP Snooping

------------------------------------------------------------------------

Status	...........................	Enabled
Disabled All-groups ports		........ None
Vlan Name (vlan id) ..... default (1)
Fast Leave		Off
Query Solicitation		Off
Static Router Ports ..... None
Group List
Group. 224.12.13.14		Entry timeout 228 secs
Ports	9
All Groups		Entry timeout 232 secs
Ports	1

------------------------------------------------------------------------

When link goes down

When we disconnect port 1 on the Snooper, the All Groups entry disappears.

Manager Switch 2> show igmpsnooping

IGMP Snooping

------------------------------------------------------------------------

Status	Enabled
Disabled All-groups ports	........ None
Vlan Name (vlan id) ..... default (1)
Fast Leave	Off
Query Solicitation	Off
Static Router Ports ..... None
Group List
Group. 224.12.13.14	Entry timeout 196 secs
Ports 9

------------------------------------------------------------------------

The Snooper still knows to send Queries and the multicast stream out port 9. However, it does not know where to send any IGMP Report messages.

Page 29 AlliedWare™ OS How To Note: IGMP