14 MSTP CONFIGURATION GUIDE
Configuring MSTP The Switch 5500 supports the Multiple Spanning Tree Protocol (MSTP), which
allows you to map one or multiple VLANs to a multiple spanning tree instance
(MSTI). Note that one VLAN can be mapped to only one MSTI. With MSTP, the
packets of a specific VLAN are transmitted in the MSTI to which the VLAN is
mapped, thus saving overhead and reducing resource utilization.
Network Diagram Figure22 Network diagram for MSTP configuration
Networking and
Configuration
Requirements
Configure MSTP in the network shown in Figure 22 to enable packets of different
VLANs to travel along different MSTIs. Do the following:
■Assign all switches in the network to the same MST region.
■Enable packets of VLAN 10, VLAN 30, VLAN 40, and VLAN 20 to travel along
MSTI 1, MSTI 3, MSTI 4, and MSTI 0 respectively.
In this network, Switch A and Switch B are operating at the distribution layer;
Switch C and Switch D are operating at the access layer. VLAN 10 and VLAN 30
are terminated at the distribution layer and VLAN 40 is terminated at the access
layer. Configure Switch A as the root bridge of MSTI 1, Switch B as the root bridge
of MSTI 3, and Switch C as the root bridge of MSTI 4.
VLAN MSTI
VLAN 10 MSTI 1
VLAN 20 MSTI 0
VLAN 30 MSTI 3
VLAN 40 MSTI 4
Permit˖all VLAN
Permit˖
VLAN20ˈ30
Permit˖
VLAN10ˈ20
Permit˖VLAN20, 40
Permit˖
VLAN20ˈ30
Permit˖
VLAN10ˈ20
Switch A Switch B
Switch C Switch D