3Com Switch 7750 Series
Command Reference Guide – MSTP Chapter 1 MSTP Configuration Commands
1-41
Use the undo stp root-protection command to restore the root protection function to
the default state on the current port.
By default, the root protection function is disabled.
Configuration errors or attacks may result in configuration BPDUs with their priorities
higher than that of a root bridge, which causes new root bridge to be elected and
network topology jitter to occur. In this case, flows that are to travel along high-speed
links may be led to low-speed links, and network congestion may occur.
You can avoid this by utilizing the root protection function. Ports with this function
enabled can only be kept as designated ports in all spanning tree instances. When a
port of this type receives configuration BPDUs with higher priorities, it changes to
Discarding state (rather than becomes a non-designated port) and stops forwarding
packets (as if it is disconnected from the link). It resumes the normal state if it does not
receive any configuration BPDUs with higher priorities for a specified period.
Related command: stp interface root-protection.
Example
# Enable the root protection function on Ethernet1/0/1 port.
<3Com> system-view
System View: return to User View with Ctrl+Z.
[3Com] interface Ethernet1/0/1
[3Com-Ethernet1/0/1] stp root-protection
1.1.39 stp tc-protection Syntax
stp tc-protection enable
stp tc-protection disable
View
System view
Parameter
None
Description
Use the stp tc-protection enable command to enable the TC-BPDU prevention
function.
Use the stp tc-protection disable command to disable the TC-BPDU prevention
function.
By default, the TC-BPDU prevention function is enabled.