247
Function:
Configure the spanning-tree flush mode for port once the topology changes .
“no spanning-tree tcflush” restores to default setting
Parameter:
Enable:the spanning-tree flush once the topology changes.
Disable:the spanning tree don’t flush when the topology changes.
Protect: the spanning-tree flush every ten seconds
Default:
Global configuration
Command mode:
Interface mode
Usage Guide:
According to MSTP , when topology changes, the port that send change
message clears MAC/ARP table (FLUSH). In fact it is not needed for some network
environment to do FLUSH with every topology change. At the same time ,as a method to
avoid network assault, we allow the network administrator to configure FLUSH mode by
the command
Note:For the complicated network, especially need to switch from one spanning tree
branch to another rapidly, the disable mode is not recommended.
Example:
Switch(Config)#interface ethernet 1/2
Switch(Config-Ethernet-1/2)#spanning-tree tcflush disable
8.4 MSTP Example
The following is a typical MSTP application scenario:
Fig 8-2Typical MSTP Application Scenario
The connections among the switches are shown in the above figure. All the switches
run in the MSTP mode by default, their bridge priority, port priority and port route cost are
SwitchB
SwitchC
SwitchD
1
1
2
2
3
5
4
2
3
1
6
7
5
4
6
7
x
x
x
x
x
