Allied Telesis AR400 Initial state, TC and sends, Query Solicit QS, QS and sends, Final state

Query solicitation (rapid recovery from topology changes) > How query solicitation works

The following figure shows how Query Solicitation works when a port goes down.

			Multicast
Initial state:	Switch 1: Querier	Switch 2: STP root	Switch 3	Switch 4
Port on Switch 3
is blocking.	Multicast			Multicast
Multicasts flow
from server to
client via Switches
1 and 4

1.Link to Switch 4

goes down.	Switch 2: STP root	Switch 3
Switch 3 stops		TC
blocking and
sends topology
change (TC)

2.Switch 2 receives

TC and sends	Switch 2: STP root
Query Solicit (QS)		QS
QS	QS

3.Switch 1 receives

QS and sends	Switch 1: Querier
General Query (GQ)	GQ	GQ	GQ	GQ

4.Host receives GQ

and responds with Membership Report

Report Report Report Report

Final state:

Multicasts flow from server to client via Switches 1, 2, 3, and 4

Switch 1: Querier Switch 2: STP root Switch 3 Switch 4

Multicast Multicast Multicast Multicast Multicast

igmp-qs.eps

Page 27 AlliedWare™ OS How To Note: IGMP