204
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 0/0/2
Switch(Config-Ethernet-0/0/2)#spanning-tree tcflush disable
Switch(Config-Ethernet-0/0/2)#
7.4 MSTP Example
The following is a typical MSTP application scenario:
Fig 7-2 Typical MSTP Application Scenario
The connections among the switches are shown in the above figure. All the switches
SwitchB
SwitchC
SwitchD
1
1
2
2
3
5
4
2
3
1
6
7
5
4
6
7
x
x
x
x
x
