Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring STP (Rev. 03)
Spanning Tree Protocol (STP)
© 2008 Foundry Networks, Inc.
Page 16 of 38
The mrouter port of Switch C that links to Switch B is blocked. If a topology change occurs and
the link between Switch C and Switch A goes down, the blocked port of Switch C turns into
forwarding state. If Spanning Tree IGMP Fast Recovery is configured on Switch C, the switch
reacts to the topology change by sending an IGMP General Query to all its non-mrouter ports. The
client(s) respond to the General Query with an IGMP report. Switch C forwards the IGMP report
to its mrouter ports and the report goes to the multicast router through Switch B and Switch D. As
a result, the traffic for client(s) connected to Switch C is transmitted through Switch B instead of
through Switch A, as shown on
Figure 10
.
Figure 10: Spanning Tree IGMP Fast Recovery Example
The STP IGMP Fast Recovery is disabled by default. To set the STP IGMP Fast Recovery, use the
spanning-tree igmp-fast-recovery
command in Protocol Configuration mode.
STP Configuration Flow
displays the STP configuration process to configure STP parameters.