Cisco Nexus 5000 Series Switch CLI Software Configuration Guide, NX-OS 4.0(1a)N1 (OL-16597-01, January 2009)

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Cisco Nexus 5000 Series Switch CLI Software Configuration Guide
OL-16597-01
Chapter 9 Configuring MST
Configuring MST
Configuring the Forwarding-Delay Time
You can set the forward delay timer for all MST instances on the switch with one command.
To configure the forward delay timer, perform this task:
This example shows how to configure the forward-delay time of the switch to 10 seconds:
switch# configure terminal
switch(config)# spanning-tree mst forward-time 10
Configuring the Maximum-Aging Time
The maximum-aging timer is the number of seconds that a switch waits without receiving spanning tree
configuration messages before attempting a reconfiguration.
You set the maximum-aging timer for all MST instances on the switch with one command (the maximum
age time only applies to the IST).
To configure the maximum-aging timer, perform this task:
This example shows how to configure the maximum-aging timer of the switch to 40 seconds:
switch# configure terminal
switch(config)# spanning-tree mst max-age 40
Configuring the Maximum-Hop Count
MST uses the path cost to the IST regional root and a hop-count mechanism similar to the IP time-to-live
(TTL) mechanism. You configure the maximum hops inside the region and apply it to the IST and all
MST instances in that region. The hop count achieves the same result as the message-age information
(triggers a reconfiguration).
Command Purpose
Step 1
switch# configure terminal
Enters configuration mode.
Step 2
switch(config)# spanning-tree mst
forward-time seconds
Configures the forward time for all MST instances.
The forward delay is the number of seconds that a port
waits before changing from its spanning tree blocking
and learning states to the forwarding state. For
seconds, the range is from 4 to 30, and the default is
15 seconds.
Command Purpose
Step 1
switch# configure terminal
Enters configuration mode.
Step 2
switch(config)# spanning-tree mst
max-age seconds
Configures the maximum-aging time for all MST
instances. The maximum-aging time is the number of
seconds that a switch waits without receiving
spanning tree configuration messages before
attempting a reconfiguration. For seconds, the range
is from 6 to 40, and the default is 20 seconds.