Allied Telesis AR400 - Manual (Page 27)

Page 27 | AlliedWare™ OS How To Note: IGMP
Query solicitation (rapid recovery from topology changes) > How query solicitation works
The following figure shows how Query Solicitation works when a port goes down.
TC
1. Link to Switch 4
goes down.
Switch 3 stops
blocking and
sends topology
change (TC)
Switch 3 Switch 2: STP root
QS QS
2. Switch 2 receives
TC and sends
Query Solicit (QS)
Switch 2: STP root
QS
GQ GQ
3. Switch 1 receives
QS and sends
General Query (GQ)
GQ
Switch 1: Querier
GQ
Report Report
4. Host receives GQ
and responds with
Membership Report
Report Report
Switch 1: Querier Switch 3 Switch 2: STP root Switch 4
Initial state:
Port on Switch 3
is blocking.
Multicasts flow
from server to
client via Switches
1 and 4
Multicast
Multicast
Multicast
Multicast Multicast
Switch 1: Querier Switch 3 Switch 2: STP root Switch 4
Final state:
Multicasts flow
from server to
client via Switches
1, 2, 3, and 4
Multicast Multicast Multicast
igmp-qs.eps