Reference Guide

• Change the region revision number in MULTIPLE-SPANNING-TREE mode (0 to 65535, default 0).
revision number
Congure and verify region name
OS10(conf-mstp)# name my-mstp-region
OS10(conf-mstp)# do show spanning-tree mst config
MST region name: my-mstp-region
Revision: 0
MSTI VID
1 100
2 200-300
Modify parameters
The root bridge sets the values for forward-delay, hello-time, max-age, and max-hops and overwrites the values set on other MST bridges.
Forward-time Time an interface waits in the Discarding state and Learning state before it transitions to the Forwarding state.
Hello-time Interval in which the bridge sends MST BPDUs.
Max-age Length of time the bridge maintains conguration information before it refreshes that information by recomputing
the MST topology.
Max-hops Maximum number of hops a BPDU travels before a receiving device discards it.
Dell EMC recommends that only experienced network administrators change MST parameters. Poorly planned modication of the MST
parameters can negatively aect network performance.
1 Change the forward-time parameter in CONFIGURATION mode (4 to 30, default 15).
spanning-tree mst forward-time seconds
2 Change the hello-time parameter in CONFIGURATION mode (1 to 10, default 2). Dell EMC recommends increasing the hello-time for
large congurations (especially congurations with more ports).
spanning-tree mst hello-time seconds
3 Change the max-age parameter in CONFIGURATION mode (6 to 40, default 20).
spanning-tree mst max-age seconds
4 Change the max-hops parameter in CONFIGURATION mode (1 to 40, default 20).
spanning-tree mst max-hops number
MST conguration
OS10(config)# spanning-tree mst
OS10(config)# spanning-tree mst forward-time 16
OS10(config)# spanning-tree mst hello-time 5
OS10(config)# spanning-tree mst max-age 10
OS10(config)# spanning-tree mst max-hops 30
View MSTP parameter values
OS10# show spanning-tree active
Spanning tree enabled protocol msti with force-version mst
MSTI 0 VLANs mapped 1,31-4093
Executing IEEE compatible Spanning Tree Protocol
Root ID Priority 32768, Address 3417.4455.667f
Root Bridge hello time 2, max age 20, forward delay 15, max hops 20
Bridge ID Priority 32768, Address 90b1.1cf4.a523
Configured hello time 10, max age 40, forward delay 30, max hops 40
CIST regional root ID Priority 32768, Address 90b1.1cf4.a523
CIST external path cost 500
Interface Designated
Name PortID Prio Cost Sts Cost Bridge ID PortID
-----------------------------------------------------------------------------
ethernet1/1/5 128.276 128 500 FWD 0 32768 3417.4455.667f 128.146
Layer 2
199