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Configuring the mode a port uses to recognize/send MSTP
packets
A port can receive/send MSTP packets in the following formats:
•
dot1s
—
802.1s-compliant standard format
•
legacy
—
Compatible format
By default, the packet format recognition mode of a port is
auto
. The port automatically distinguishes the
two MSTP packet formats, and determines the format of packets it will send based on the recognized
format.
You can configure the MSTP packet format on a port. When working in MSTP mode after the
configuration, the port sends and receives only MSTP packets of the format you have configured to
communicate with routers that send packets of the same format.
To configure the MSTP packet format to be supported on a port or a group of ports:
Step Command
Remarks
1.
Enter system view.
system-view
N/A
2.
Enter interface view or port
group view.
•
Enter Ethernet interface view or
Layer 2 aggregate interface view:
interface
interface-type
interface-number
•
Enter port group view:
port-group manual
port-group-name
Use one of the commands.
3.
Configure the mode the port uses
to recognize/send MSTP
packets.
stp compliance
{
auto
|
dot1s
|
legacy
}
The default setting is
auto
.
NOTE:
•
MSTP provides the MSTP packet format incompatibility guard function. In MSTP mode, if a port is
configured to recognize/send MSTP packets in a mode other than
auto
, and receives a packet in a
format different from the specified type, the port will become a designated port and remain in the
discarding state to prevent the occurrence of a loop.
•
MSTP provides the MSTP packet format frequent change guard function. If a port receives MSTP packets
of different formats frequently, the MSTP packet format configuration contains errors. If the port is
working in MSTP mode, it will be shut down for protection. The closed ports can be reactivated after a
detection interval. For more information about the detection interval, see
Fundamentals Configuration
Guide.
Enabling the spanning tree feature
You must enable the spanning tree feature for the router before any other spanning tree related
configurations can take effect.
To enable the spanning tree feature:
