Operation Manual

STP Commands
STP Commands
13 – 371
state STP state of the port:
❑ Blocking—The port is not forwarding Layer 2 traffic but is
listening to and forwarding STP control traffic.
❑ Disabled—The port is not forwarding any traffic, including STP
control traffic. The port might be administratively disabled or
the link might be disconnected.
❑ Forwarding—The port is forwarding Layer 2 traffic.
❑ Learning—The port is learning the locations of other devices in
the spanning tree before changing state to forwarding.
❑ Listening—The port is comparing its own STP information with
information in STP control packets received by the port to
compute the spanning tree and change state to blocking or
forwarding.
port_id STP port ID.
port_number STP port number.
path cost Cost to use this port to reach the root bridge. This is part of the total
path cost (designated cost).
message age Age of the protocol information for a port and the value of the
maximum age parameter (shown in parenthesis) recorded by the
switch.
designated_root MAC address of the root bridge.
designated cost Total path cost to reach the root bridge.
designated_bridge Bridge to which this MX forwards traffic away from the root bridge.
designated_port STP port through which this MX forwards traffic away from the root
bridge.
top_change_ack Value of the topology change acknowledgment flag in the next
configured bridge protocol data unit (BPDU) to be transmitted on
the associated port. The flag is set in reply to a topology change
notification BPDU.
config_pending Indicates whether a configured BPDU is to be transmitted on
expiration of the hold timer for the port.
port_inconsistency Indicates whether the port is in an inconsistent state.
config BPDU’s xmitted Number of BPDUs transmitted from the port. A number in
parentheses indicates the number of configured BPDUs transmitted
by the MX for this VLAN’s spanning tree.
config BPDU’s received Number of BPDUs received by this port. A number in parentheses
indicates the number of configured BPDUs received by the MX
switch for this VLAN’s spanning tree.
tcn BPDU’s xmitted Number of topology change notification (TCN) BDPUs transmitted
on this port.
tcn BPDU’s received Number of TCN BPDUs received on this port.
forward transition count Number of times the port state transitioned to the forwarding state.
scp failure count Number of service control point (SCP) failures.
root inc trans count Number of times the root bridge changed.
inhibit loopguard State of the loop guard. In the current release, the state is always
FALSE.
loop inc trans count Number of loops that have occurred.
forward delay timer Status of the forwarding delay timer. This timer monitors the time
spent by a port in the listening and learning states.
forward delay timer value Current value of the forwarding delay timer, in seconds.
Table 13– 3. Output for show spantree statistics (continued)
Field Description