This article explains the meaning of the following message logged by l2cpd:
l2cpd[17535]: %DAEMON-1-TOPO_CH: for Instance 0 in routing-instance default received on port xe-x/x/x.32767
The following log messages are logged by l2cpd when there's an MSTP topology change:
Dec 25 15:38:11.344 2014 hostname l2cpd[17535]: %DAEMON-1-TOPO_CH: for Instance 0 in routing-instance default received on port xe-x/x/x.32767Dec 25 15:42:37.465 2014 hostname l2cpd[17535]: %DAEMON-1-TOPO_CH: for Instance 1 in routing-instance default received on port xe-y/y/y.32767
In the MSTP scenario, when there's an MSTP topology change, the l2cpd process will log a message for this event. The l2cpd process will log which instance and interface is affected by this topology change event. When the MSTP topology is stable and the MSTP protocol has finished its convergence, these log messages will disappear.
An MSTP topology change event can be observed by show spanning-tree bridge , as follows:
show spanning-tree bridge
user@router# run show spanning-tree bridgeSTP bridge parametersRouting instance name : GLOBALContext ID : 0Enabled protocol : MSTPSTP bridge parameters for CISTRoot ID : 32768.88:e0:f3:bc:87:d1CIST regional root : 32768.88:e0:f3:bc:87:d1CIST internal root cost : 0Hello time : 2 secondsMaximum age : 20 secondsForward delay : 15 secondsNumber of topology changes : 3 >>> Number of topology changes for MSTP Instance 0 Time since last topology change : 6 secondsLocal parametersBridge ID : 32768.88:e0:f3:bc:87:d1STP bridge parameters for MSTI 1MSTI regional root : 32769.88:e0:f3:bc:87:d1Hello time : 2 secondsMaximum age : 20 secondsForward delay : 15 secondsNumber of topology changes : 3 >>> Number of topology changes for MSTP Instance 1 Time since last topology change : 6 secondsLocal parametersBridge ID : 32769.88:e0:f3:bc:87:d1
During the topology change event, the following logs are observed:
Dec 25 15:38:11.344 2014 hostname l2cpd[17535]: %DAEMON-1-TOPO_CH: for Instance 0 in routing-instance default received on port xe-x/x/x.32767Dec 25 15:38:11.344 2014 hostname l2cpd[17535]: %DAEMON-1-TOPO_CH: for Instance 1 in routing-instance default received on port xe-y/y/y.32767Dec 25 15:42:37.465 2014 hostname l2cpd[17535]: %DAEMON-1-TOPO_CH: for Instance 0 in routing-instance default received on port xe-y/y/y.32767Dec 25 15:42:37.465 2014 hostname l2cpd[17535]: %DAEMON-1-TOPO_CH: for Instance 1 in routing-instance default received on port xe-y/y/y.32767Dec 25 15:42:37.541 2014 hostname l2cpd[17535]: %DAEMON-1-TOPO_CH: for Instance 0 in routing-instance default received on port xe-x/x/x.32767
These messages are a warning and there is no service impact as long as MSTP finally reconverges. If these messages repeat continuously, it usually means that the MSTP topology is flapping and you should check why the MSTP topology is flapping. When the MSTP topology is stable and the MSTP protocol finishes its convergence, these log messages will disappear.