Configuring The Root Bridge Or A Secondary Root Bridge - HP A5830 Configuration Manual

you change the spanning tree mode back. To prevent loss of mappings, do not manually configure VLAN-
to-instance mappings in PVST mode.

Configuring the root bridge or a secondary root bridge

Have MSTP determine the root bridge of a spanning tree through MSTP calculation, or specify the current
device as the root bridge or as a secondary root bridge using the commands that the system provides.
A device has independent roles in different spanning trees. It can act as the root bridge in one spanning
tree and as a secondary root bridge in another. However, one device cannot be the root bridge and a
secondary root bridge in the same spanning tree.
A spanning tree can have one root bridge only. If two or more devices are designated as the root bridge
in a spanning tree at the same time, the device with the lowest MAC address wins.
When the root bridge of an instance fails or is shut down, the secondary root bridge (if you have
specified one) can take over the role of the primary root bridge. However, if you specify a new primary
root bridge for the instance then, the one you specify, not the secondary root bridge will become the root
bridge. If you have specified multiple secondary root bridges for an instance, when the root bridge fails,
the secondary root bridge with the lowest MAC address is selected as the new root bridge.
Configuring the current device as the root bridge of a specific spanning tree
To configure the current device as the root bridge of a specific spanning tree:
Step...
1. Enter system view
2. Configure the current device
as the root bridge (in
STP/RSTP mode)
3. Configure the current device
as the root bridge (in PVST
mode)
4. Configure the current device
as the root bridge (in MSTP
mode)
Configuring the current device as a secondary root bridge of a specific spanning tree
To configure the current device as a secondary root bridge of a specific spanning tree:
Step...
1. Enter system view
2. Configure the current device as a
secondary root bridge (in STP/RSTP
mode)
3. Configure the current device as a
secondary root bridge (in PVST mode)
4. Configure the current device as a
secondary root bridge (in MSTP mode)
Specify one root bridge for each spanning tree, regardless of the device priority settings. While a device
is set as the root bridge or a secondary root bridge, you cannot change its priority.
Command...
system-view
stp root primary
stp vlan vlan-list root primary
stp [ instance instance-id ] root
primary
Command...
system-view
stp root secondary
stp vlan vlan-list root secondary
stp [ instance instance-id ] root
secondary
65
Remarks
—
Required
Use any command
By default, a device does not
function as the root bridge
Remarks
—
Required
Use any command
By default, a device
does not function as a
secondary root bridge