Specifications

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Cisco ME 3400 Ethernet Access Switch Command Reference
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Chapter 2 Cisco ME 3400 Ethernet Access Switch Cisco IOS Commands
spanning-tree mst max-hops
spanning-tree mst max-hops
Use the spanning-tree mst max-hops global configuration command to set the number of hops in a
region before the bridge protocol data unit (BPDU) is discarded and the information held for an interface
is aged. Use the no form of this command to return to the default setting.
spanning-tree mst max-hops hop-count
no spanning-tree mst max-hops
Syntax Description
Defaults The default is 20 hops.
Command Modes Global configuration
Command History
Usage Guidelines On the Cisco ME switch, spanning-tree MST configuration is supported only on network node interfaces
(NNIs) or on enhanced network interfaces (ENIs) on which Spanning Tree Protocol (STP) has been
enabled. To set a port as an NNI or ENI, enter the port-type {eni | nni} interface configuration
command. To enable STP on an ENI, enter the spanning-tree interface configuration command.
User network interfaces (UNIs) do not participate in STP.
The root switch of the instance always sends a BPDU (or M-record) with a cost of 0 and the hop count
set to the maximum value. When a switch receives this BPDU, it decrements the received remaining hop
count by one and propagates the decremented count as the remaining hop count in the generated
M-records. A switch discards the BPDU and ages the information held for the interface when the count
reaches 0.
Changing the spanning-tree mst max-hops command affects all spanning-tree instances.
Examples This example shows how to set the spanning-tree max-hops to 10 for all multiple spanning-tree (MST)
instances:
Switch(config)# spanning-tree mst max-hops 10
You can verify your setting by entering the show spanning-tree mst privileged EXEC command.
hop-count Number of hops in a region before the BPDU is discarded. The range is 1 to 255 hops.
Release Modification
12.2(25)EX This command was introduced.
12.2(25)SEG The hop-count range changed to 1 to 255.