Multiple Instance Spanning-Tree Operation

Troubleshooting an MSTP Configuration

Field

Description

 

 

Exceeded Max Hops

Number of times that an MSTI MSG packet is received from a bridge internal to the MST

MSTI MSGs

region with an MSTI Remaining Hops value less than or equal to 1. This may occur if the

 

receiving bridge is located too far from the MSTI regional root bridge (beyond the

 

configured size of the MST region on the MSTI regional root bridge) or if a BPDU packet

 

with invalid MSTI regional root bridge information is continuously circulating between

 

bridges in an MST region and needs to be aged out. This counter is maintained on a per-

 

MSTI per-port basis.

 

 

Topology Changes

Number of times that a Topology Change event is detected by the CIST or MSTI port and

Detected

the port triggers a topology change propagation throughout the network. A Topology

 

Change event occurs when a non-edge port enters forwarding state. This counter is

 

maintained on a per-CIST per-port and on a per-MSTI per-port basis.

 

 

Topology Changes Tx

Number of times that Topology Change information is propagated (sent out) through the port

 

to the rest of the network.

 

For a CIST port, the counter is the number of times that a CFG, RST or MST BPDU with the

 

TC flag set is transmitted out of the port.

 

For an MSTI port, the counter is the number of times that a MSTI configuration message

 

with the TC flag set is transmitted out of the port.

 

This counter is maintained on a per-CIST per-port and on a per-MSTI per-port bases.

 

 

Topology Changes Rx

Number of times that Topology Change information is received from the peer port.

 

For a CIST port, the counter is the number of times that a CFG, RST or MST BPDU with the

 

TC flag set is received.

 

For an MSTI port, the counter is the number of times that an MSTI configuration message

 

with the TC flag set is received.

 

This counter is maintained on a per-CIST per-port and on a per-MSTI per-port basis.

 

 

Topology Change ACKs

Number of times that the Topology Change acknowledgement is transmitted through the

Tx

port (number of CFG, RST or MST BPDUs transmitted with the Topology Change

 

Acknowledge flag set). This counter is maintained by the CIST (default MST instance 0) on

 

a per-port basis.

 

 

Topology Change ACKs

Number of times the Topology Change acknowledgement is received on the port (number

Rx

of CFG, RST or MST BPDUs received with the Topology Change Acknowledge flag set). This

 

counter is maintained by the CIST (default MST instance 0) on a per-port basis.

 

 

TCN BPDUs Tx

Number of Topology Change Notification BPDUs that are transmitted through the port. This

 

counter is maintained by the CIST (default MST instance 0) on a per-port basis.

 

 

TCN BPDUs Rx

Number of Topology Change Notification BPDUs that are received on the port. This counter

 

is maintained by the CIST (default MST instance 0) on a per-port basis.

 

 

CFG BPDUs Tx

Number of (802.1D) Configuration BPDUs that are transmitted through the port. This counter

 

is maintained by the CIST (default MST instance 0) on a per-port basis.

 

 

CFG BPDUs Rx

Number of (802.1D) Configuration BPDUs that are received on the port. This counter

 

maintained by the CIST (default MST instance 0) on a per-port basis.

 

 

4-68