Reference Guide

Non-Dell hardware
OS10 supports only one MST region. For a bridge to be in the same MST region as another, the three unique attributes (name, revision, and
VLAN-to-instance-mapping) must match. The default values for name and revision number match on all Dell hardware. If you have non-Dell
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 (default is the system MAC address).
• Revision — A 2-byte number (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 (up to 32 characters).
name name
• 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
Layer 2
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