Configuring The Bridge Priority For A Switch; Configuring The Max Hops In An Mst Region - 3Com Switch 7700 Configuration Manual

Configuring the Bridge
Priority for a Switch
Configuring the Max
Hops in an MST Region
region itself. In MSTP mode, the switch ports send MSTP or STP packets (when
connected to the STP switch) and the switch provides the multiple spanning tree
function.
You can use the following command to configure MSTP running mode. MSTP can
intercommunicate with STP. If there is a STP switch in the switching network, you
can use the command to configure the current MSTP to run in STP-compatible
mode, otherwise, configure it to run in MSTP mode.
Perform the following configuration in system view.
Table 5 Configure the MSTP Running Mode
Operation
Configure MSTP to run in STP-compatible
mode
Configure MSTP to run in MSTP mode.
Restore the default MSTP running mode
Generally, if there is a STP switch on the switching network, the port connected to
it will automatically transit from MSTP mode to STP-compatible mode. The port
cannot automatically transition itself back to MSTP mode after the STP switch is
removed. In this case, you can perform the mcheck operation to transit the port to
MSTP mode by force.
By default, MSTP runs in MSTP mode.
Whether or not a switch can be elected as the spanning tree root, depends on its
bridge priority. The switch configured with a lower bridge priority is more likely to
become the root. An MSTP switch can have different priorities in different STIs.
You can use the following command to configure the bridge priorities of the
designated switch in different STIs.
Perform the following configuration in system view.
Table 6 Configure the Priority for a Switch
Operation
Configure the priority of the designated
switch.
Restore the default priority of the designated
switch.
When configuring the switch priority with the instance instance-id parameter,
with a value of 0, you are configuring the CIST priority of the switch.
In the process of spanning tree root election of two or more switches, with the
lowest priorities, the one has a smaller MAC address will be elected as the root.
By default, the switch priority is 32768.
The scale of an MST region is limited by the max hops in the MST region; which is
configured on the region root. As the BPDU travels from the spanning tree root,
Configuring MSTP
Command
stp mode stp
stp mode mstp
undo stp mode
Command
stp instance instance-id priority priority
undo stp instance instance-id priority
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