Cisco Systems N3KC3064TFAL3 Configuring the Maximum-Hop Count, mst max-age seconds, Procedure

Configuring Multiple Spanning Tree

Configuring the Maximum-Hop Count

	Command or Action	Purpose
Step 2	switch(config)# spanning-tree	Configures the maximum-aging time for all MST instances.
	mst max-age seconds	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.

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).

Procedure

	Command or Action	Purpose
Step 1	switch# configure terminal	Enters configuration mode.
Step 2	switch(config)# spanning-tree mst	Specifies the number of hops in a region before the
	max-hops hop-count	BPDU is discarded, and the information held for a port
		is aged. For hop-count, the range is from 1 to 255, and
		the default value is 20 hops.

This example shows how to set the maximum hops to 40:

switch# configure terminal

switch(config)# spanning-tree mst max-hops 40

Configuring PVST Simulation Globally

You can block this automatic feature either globally or per port. You can enter the global command, and change the PVST simulation setting for the entire switch while you are in interface command mode.

Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)

OL-26590-01 109