R0106-HP MSR Router Series Layer 2 - LAN Switching Configuration Guide(V7)

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 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.

Enabling the spanning tree feature

You must enable the spanning tree feature for the device before any other spanning tree related

configurations can take effect. In STP, RSTP, or MSTP mode, make sure the spanning tree feature is

enabled globally and on the desired ports. In PVST mode, make sure the spanning tree feature is

enabled globally, in the desired VLANs, and on the desired ports.

To exclude specific ports from spanning tree calculation and save CPU resources, disable the spanning

tree feature for these ports with the undo stp enable command. Make sure no loops occur in the network

after you disable the spanning tree feature on these ports.