Spanning-Tree Operation
802.1s Multiple Spanning Tree Protocol (MSTP)
Syntax: spanning-tree < port-list > root-guard
MSTP only. When a port is enabled as root-guard, it cannot
be selected as the root port even if it receives superior STP
BPDUs. The port is assigned an “alternate” port role and
enters a blocking state if it receives superior STP BPDUs.
The BPDUs received on a port enabled as root-guard are
ignored. All other BPDUs are accepted and the external
devices may belong to the spanning tree as long as they do
not claim to be the Root device.
Syntax: spanning-tree < port-list > tcn-guard
When tcn-guard is enabled for a port, it causes the port to
stop propagating received topology change notifications
and topology changes to other ports.
(Default: No - disabled)
Configuring MST Instance Parameters
Command Page
spanning-tree instance < 1..16 > vlan < vid> [ vid..vid ] page
no spanning-tree instance < 1..16 > 5-63
spanning-tree instance < 1..16 > priority < 0..15 > page
5-66
spanning-tree priority < 0..15 > page
5-67
Syntax: spanning-tree instance < 1..16 > vlan < vid [ vid..vid ] >
no spanning-tree instance < 1..16 >
Configuring MSTP on the switch automatically configures the
IST instance and places all statically configured VLANs on the
switch into the IST instance. This command creates a new
MST instance (MSTI) and moves the VLANs you specify from
the IST to the MSTI. At least one VLAN must be mapped to a
MSTI when you create it. (A VLAN cannot be mapped to more
than one instance at a time.) You can create up to 16 MSTIs
in a region. Use the no form of the command to remove a VLAN
from an MSTI. (Removing a VLAN from an MSTI returns the
VLAN to the IST instance, where it can either remain or be re-
assigned to another MSTI configured in the region.)
The no form of the command deletes the specified MSTI and
returns all VLAN assignments to the region’s IST instance.
5-66
To Next Page
Loading...
