3Com 4210, 5500G, 4200G manual # Enable the root guard function on each designated port

86CHAPTER 14: MSTP CONFIGURATION GUIDE

#Configure Switch C and Switch B to back up each other, and set the bridge priority of Switch B to 4096.

[3Com] stp priority 4096

# Enable the root guard function on each designated port.

[3Com] interface Ethernet 1/0/4 [3Com-Ethernet1/0/4] stp root-protection

[3Com-Ethernet1/0/4] quit [3Com] interface Ethernet 1/0/5

[3Com-Ethernet1/0/5] stp root-protection

[3Com-Ethernet1/0/5] quit [3Com] interface Ethernet 1/0/6

[3Com-Ethernet1/0/6] stp root-protection

[3Com-Ethernet1/0/6] quit

#Adopt the default MSTP operation mode, time-related parameters, and port parameters.

3Configuration on Switch C

# Enable MSTP.

<3Com> system-view

[3Com] stp enable

#Enabling MSTP globally on the switch enables RSTP on all the ports. Disable MSTP on the ports that are not involved in RSTP calculation, for example Ethernet 1/0/8.

[3Com] interface Ethernet 1/0/8

[3Com-Ethernet1/0/8] stp disable

[3Com-Ethernet1/0/8] quit

#Configure Switch C and Switch B to back up each other, and set the bridge priority of Switch C to 8192.

[3Com] stp priority 8192

# Enable the root guard function on each designated port.

[3Com] interface Ethernet 1/0/1 [3Com-Ethernet1/0/1] stp root-protection

[3Com-Ethernet1/0/1] quit [3Com] interface Ethernet 1/0/2

[3Com-Ethernet1/0/2] stp root-protection

[3Com-Ethernet1/0/2] quit [3Com] interface Ethernet 1/0/3

[3Com-Ethernet1/0/3] stp root-protection

[3Com-Ethernet1/0/3] quit

#Adopt the default MSTP operation mode, time-related parameters, and port parameters.

4Configuration on Switch D