3Com Switch 7750 Series
Command Reference Guide – MSTP Chapter 1 MSTP Configuration Commands
1-4
z If only a port list is specified, the command displays information about all spanning
tree instances on these ports in the order of the port number.
z If both a spanning tree instance and a port list are specified, the command
displays spanning tree information about the specified spanning tree instance and
the specified ports in order of spanning tree instance ID.
MSTP state information includes:
z Global CIST parameters: Protocol operation mode, switch priority in the CIST
instance, MAC address, Hello time, Max age, Forward delay, Max hops, the
common root of the CIST, the external path cost for the switch to reach the CIST
common root, region root, the internal path cost for the switch to reach the region
root, CIST root port of the switch, the state of the BPDU (bridge protocol data unit)
protection function (enabled or disabled), and the state of the digest snooping
feature (enabled or disabled).
z CIST port parameters: Port protocol, port role, port priority, path cost, designated
bridge, designated port, edge port/non-edge port, whether or not the link on the
port is a point-to-point link, the maximum transmitting speed, type of the enabled
protection function, state of the digest snooping feature (enabled or disabled),
VLAN mappings, Hello time, Max age, Forward delay, Message-age time, and
Remaining-hops.
z Global MSTI parameters: MSTI instance ID, bridge priority of the instance, region
root, internal path cost, MSTI root port, and master bridge.
z MSTI port parameters: Port state, role, priority, path cost, designated bridge,
designated port, and Remaining Hops.
The statistical information includes: the numbers of the TCN BPDUs, the configuration
BPDUs, the RST BPDUs, and the MST BPDUs transmitted/received by each port.
Related command: reset stp.
Example
# Display the state and statistical information about a spanning tree.
<3Com> display stp instance 0 interface Ethernet 1/0/1 to Ethernet 1/0/4 brief
MSTID Port Role STP State Protection
0 Ethernet1/0/1 ALTE DISCARDING LOOP
0 Ethernet1/0/2 DESI FORWARDING NONE
0 Ethernet1/0/3 DESI FORWARDING NONE
0 Ethernet1/0/4 DESI FORWARDING NONE
Table 1-2 Description on the fields of the display stp command
Field Description
MSTID ID of a spanning tree instance in the MST region
Port Port index