H3C S7500 Series Ethernet Switches Command Manual

Command Manual – MSTP
H3C S7500 Series Ethernet Switches Chapter 1
MSTP Configuration Commands
1-40
You can configure one or more secondary root bridges for an MSTI. If the switch
operating as the root bridge fails or is turned off, the secondary root bridge with the
least MAC address becomes the root bridge.
You can also specify the network diameter and the Hello time of the switch that you are
configuring as a secondary root bridge. The switch will then figures out the other two
time parameters: Forward delay and Max age. You can configure only one root bridge
for an MSTI but you can configure one or more secondary root bridges for an MSTI.
Once a switch is configured as the root bridge or a secondary root bridge, its priority
cannot be modified.
Examples
# Configure the current switch as a secondary root bridge of MSTI 4, setting the
network diameter of the switched network to 5 and the Hello time to 300 centiseconds.
<H3C> system-view
System View: return to User View with Ctrl+Z.
[H3C] stp instance 4 root secondary bridge-diameter 5 hello-time 300
1.1.38 stp root-protection
Syntax
stp root-protection
undo stp root-protection
View
Ethernet port view
Parameters
None
Description
Use the stp root-protection command to enable the root guard function on the current
port.
Use the undo stp root-protection command to restore the root guard function to the
default state on the current port.
By default, the root guard 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.