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Configuring the mode a port uses to recognize and
send MSTP packets
A port can receive and 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 that it will send based on the recognized
format.
You can configure the MSTP packet format on a port. Then, the port sends only MSTP packets of the
configured format to communicate with devices that send packets of the same format.
A port in
auto
mode sends 802.1s MSTP packets by default. When the port receives an MSTP packet of
a legacy format, the port starts to send packets only of the legacy format. This prevents the port from
frequently changing the format of sent packets. To configure the port to send 802.1s MSTP packets, shut
down and then bring up the port.
When the number of existing MSTIs exceeds 48, the port can send only 802.1s MSTP packets.
To configure the MSTP packet format to be supported on a port:
Step Command Remarks
1.
Enter system view.
system-view
N/A
2.
Enter Layer 2 Ethernet or
aggregate interface view.
interface
interface-type interface-number
N/A
3.
Configure the mode that the
port uses to recognize/send
MSTP packets.
stp compliance
{
auto
|
dot1s
|
legacy
}
The default setting is
auto
.
Enabling outputting port state transition information
In a large-scale spanning tree network, you can enable devices to output the port state transition
information. Then, you can monitor the port states in real time.
To enable outputting port state transition information:
Step Command Remarks
1.
Enter system view.
system-view
N/A
2.
Enable outputting port state
transition information.
•
In STP/RSTP mode:
stp port-log instance 0
•
In PVST mode:
stp port-log
vlan
vlan-id-list
•
In MSTP mode:
stp port-log
{
all
|
instance
instance-list
}
By default, this function is
enabled.