3com 5500-SI Manual De Usuario

168

HAPTER

13: MSTP C

ONFIGURATION

MSTP Implementation

on Switches

MSTP is compatible with both STP and RSTP. That is, switches running MSTP can
recognize STP and RSTP packets and use them to calculate spanning trees. In addition
to the basic MSTP functions, a S5500 series switch also provides many special
functions for ease of management to further meet the needs of users, as listed in the
following.

■

Root bridge retaining

■

Root bridge backup

■

Root protection

■

BPDU protection

■

Loop prevention

Root Bridge
Configuration

Table 141 lists the MSTP configuration tasks for root bridges.

With both GVRP and MSTP enabled on switches, GVRP packets will be forwarded
along the CIST. If you want to broadcast packets of a specific VLAN through GVRP, be
sure to map the VLAN to the CIST when configuring the MSTP VLAN mapping table.
The CIST of a network is the spanning tree instance numbered 0.

Table 141 Root bridge configuration

Operation

Description

Related section

Enable MSTP

Required

Normally, to reduce network
topology jitters caused by
configuration, you are
recommended to enable MSTP
after completing other related
configurations.

Enabling MSTP

Configure an MST region

Required

Configuring an MST Region

Set the switch as the
root/secondary root bridge

Required

Setting a switch as the root bridge
of a spanning tree

Configure the bridge
priority of the switch

Optional

The priority of a switch cannot
be changed after the switch is
specified as the root bridge or
a secondary root bridge.

Setting a switch as a secondary
root bridge of a spanning tree

Configure MSTP operation
mode