Foundry NetIron M2404C and M2404F Metro Access Switches
Configuring STP (Rev. 03)
Spanning Tree Protocol (STP)
© 2008 Foundry Networks, Inc.
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Figure 7: Topology Change Example with TCN Message
In
Figure 8
, the root bridge generates messages with the TC flag set, causing all the bridges to
reduce their address aging timer to forward-delay time.
Figure 8: Topology Change Example with TC Message
Line Error Detection
The application software allows the Root port and the Alternate port to be interchanged when the
CRC errors on the line reach a critical level. When such a condition occurs, the path cost of the
Root port automatically changes into the high path cost value, triggering the interchange of the
Root and Alternate port statuses.