1-15 
In addition to the basic MSTP functions, the 3Com switches 4210 also provide the following functions 
for users to manage their switches. 
z  Root bridge hold 
z  Root bridge backup 
z  Root guard 
z  BPDU guard 
z  Loop guard 
z  TC-BPDU attack guard 
z  BPDU dropping 
Protocols and Standards 
MSTP is documented in: 
z  IEEE 802.1D: spanning tree protocol 
z  IEEE 802.1w: rapid spanning tree protocol 
z  IEEE 802.1s: multiple spanning tree protocol 
MSTP Configuration Task List 
Before configuring MSTP, you need to know the position of each device in each MSTI: root bridge or 
leave node. In each MSTI, one, and only one device acts as the root bridge, while all others as leaf 
nodes. 
Complete these tasks to configure MSTP: 
Task  Remarks 
Enabling MSTP 
Required 
To prevent network topology jitter 
caused by other related configurations, 
you are recommended to enable MSTP 
after other related configurations are 
performed. 
Configuring an MST Region  Required 
Specifying the Current Switch as a Root 
Bridge/Secondary Root Bridge
 
Required 
Configuring the Bridge Priority of the 
Current Switch
 
Optional 
The priority of a switch cannot be 
changed after the switch is specified as 
the root bridge or a secondary root 
bridge. 
Configuring How a Port Recognizes and 
Sends MSTP Packets
 
Optional 
Configuring the MSTP Operation Mode  Optional 
Configuring the Maximum Hop Count of an 
MST Region
 
Optional 
Configuring the Network Diameter of the 
Switched Network
 
Optional 
The default value is recommended. 
Configuring 
Root Bridge
 
Configuring the MSTP Time-related 
Parameters
 
Optional 
The default values are recommended.