Connectivity Guide

Non-Dell EMC hardware
OS10 supports only one MST region. For a bridge to be in the same MST region as another, the three unique name, revision, and VLAN-to-
instance-mapping attributes must match. The default values for the name and revision number match on all Dell EMC hardware. If you have
non-Dell EMC hardware that participates in MST, ensure these values match on all devices.
A region is a combination of three unique attributes:
• Name — A mnemonic string you assign to the region. The default is the system MAC address.
• Revision — A 2-byte number. The default is 0.
• VLAN-to-instance mapping — Placement of a VLAN in an MSTI.
Region name or revision
You can change the MSTP region name or revision.
• Change the region name in MULTIPLE-SPANNING-TREE mode. A maximum of 32 characters.
name name
• Change the region revision number in MULTIPLE-SPANNING-TREE mode, from 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.
NOTE: Dell EMC recommends that only experienced network administrators change MST parameters. Poorly planned
modication of MST parameters can negatively aect network performance.
1 Change the forward-time parameter in CONFIGURATION mode, from 4 to 30, default 15.
spanning-tree mst forward-time seconds
2 Change the hello-time parameter in CONFIGURATION mode, from 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, from 6 to 40, default 20.
spanning-tree mst max-age seconds
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