User's Manual

Table Of Contents

Configuration Guide of XGS-5240-Series

217

Switch4(Config-Mstp-Region)#exit

Switch4(config)#interface e1/0/1-7

Switch4(Config-Port-Range)#switchport mode trunk

Switch4(Config-Port-Range)#exit

Switch4(config)#spanning-tree

Switch4(config)#spanning-tree mst 4 priority 0

After the above configuration, Switch1 is the root bridge of the instance 0 of the entire

network. In the MSTP region which Switch2, Switch3 and Switch4 belong to, Switch2 is the

region root of the instance 0, Switch3 is the region root of the instance 3 and Switch4 is the

region root of the instance 4. The traffic of VLAN 20 and VLAN 30 is sent through the topology

of the instance 3. The traffic of VLAN 40 and VLAN 50 is sent through the topology of the

instance 4. And the traffic of other VLANs is sent through the topology of the instance 0. The

port 1 in Switch2 is the master port of the instance 3 and the instance 4.

The MSTP calculation generates 3 topologies: the instance 0, the instance 3 and the

instance 4 (marked with blue lines). The ports with the mark “x” are in the status of discarding.

The other ports are the status of forwarding. Because the instance 3 and the instance 4 are

only valid in the MSTP region, the following figure only shows the topology of the MSTP

region.

Fig 1-3 The Topology Of the Instance 0 after the MSTP Calculation

SW1

SW2

SW3

SW4

1 1X

2 2

3X 3