Reference Guide

0:0001.e809.c24a
R3(conf-mstp)#show config
!
protocol spanning-tree mstp
no disable
MSTI 1 VLAN 100
MSTI 2 VLAN 200,300
MSTI 2 bridge-priority 0
Interoperate with Non-Dell Networking OS Bridges
Dell Networking OS supports only one MSTP region.
A region is a combination of three unique qualities:
• Name is a mnemonic string you assign to the region. The default region name on Dell Networking OS
is null.
• Revision is a 2-byte number. The default revision number on Dell Networking OS is 0.
• VLAN-to-instance mapping is the placement of a VLAN in an MSTI.
For a bridge to be in the same MSTP region as another, all three of these qualities must match exactly.
The default values for name and revision match on all Dell Networking OS equipment. If you have non-
Dell Networking OS equipment that participates in MSTP, ensure these values match on all the
equipment.
NOTE: Some non-Dell Networking OS equipment may implement a non-null default region name.
SFTOS, for example, uses the Bridge ID, while others may use a MAC address.
Modifying Global Parameters
The root bridge sets the values for forward-delay, hello-time, max-age, and max-hops and overwrites the
values set on other MSTP bridges.
• Forward-delay — the amount of time an interface waits in the Listening state and the Learning state
before it transitions to the Forwarding state.
• Hello-time — the time interval in which the bridge sends MSTP bridge protocol data units (BPDUs).
• Max-age — the length of time the bridge maintains configuration information before it refreshes that
information by recomputing the MST topology.
• Max-hops — the maximum number of hops a BPDU can travel before a receiving switch discards it.
NOTE: Dell Networking recommends that only experienced network administrators change MSTP
parameters. Poorly planned modification of MSTP parameters can negatively affect network
performance.
To change the MSTP parameters, use the following commands on the root bridge.
1. Change the forward-delay parameter.
PROTOCOL MSTP mode
forward-delay seconds
The range is from 4 to 30.
618
Multiple Spanning Tree Protocol (MSTP)