Configuring The Device Priority; Configuring The Maximum Hops Of An Mst Region - H3C SR8800 Configuration Manual

Step
2. Configure the current router as a
secondary root bridge.
NOTE:
You can specify one root bridge for each spanning tree, regardless of the device priority settings. Once
•
you specify a router as the root bridge or a secondary root bridge, you cannot change its priority.
• You can configure the current router as the root bridge by setting the device priority to 0. For the device
priority configuration, see

Configuring the device priority

Device priorities participate in spanning tree calculation. The priority of a router determines whether the
router can be elected as the root bridge of a spanning tree. A lower value indicates a higher priority. By
setting the priority of a router to a low value, you can specify the router as the root bridge of the spanning
tree. A spanning tree router can have different priorities in different MSTIs.
To configure the priority of a router in a specified MSTI:
Step
1. Enter system view.
2. Configure the priority of the
current router.
CAUTION:
After configuring a router as the root bridge or a secondary root bridge, you cannot change the priority
•
of the router.
During root bridge selection, if all routers in a spanning tree have the same priority, the one with the
•
lowest MAC address will be selected as the root bridge of the spanning tree.

Configuring the maximum hops of an MST region

By setting the maximum hops of an MST region, you can restrict the region size. The maximum hops
configured on the regional root bridge will be used as the maximum hops of the MST region.
The regional root bridge always sends a configuration BPDU with a hop count set to the maximum value.
When a router receives this configuration BPDU, it decrements the hop count by 1 and uses the new hop
count in the BPDUs it propagates. When the hop count of a BPDU reaches 0, it is discarded by the router
that received it. Routers beyond the reach of the maximum hop can no longer take part in spanning tree
calculation, and the size of the MST region is confined.
Command
•
In STP/RSTP mode:
stp root secondary
•
In MSTP mode:
stp [ instance instance-id ] root
secondary
"Configuring the device
Command
system-view
•
In STP/RSTP mode:
stp priority priority
•
In MSTP mode:
stp [ instance instance-id ] priority
priority
44
Remarks
Use one of the commands.
By default, a router does not
function as a secondary root
bridge.
priority."
Remarks
N/A
Use one of the commands.
The default setting is
32768.