Hello there,
Just wanted to provide some steps to troubleshoot M2PA or M3UA/SUA based links. Although it is uncommon to see them flapping, it actually could occur due to different reasons.
In case of observing link flapping, I usually follow the below steps to further isolate the problem:
a) Obtain "show logging" output; which will include the link failure reason like the example below:
%CS7MTP3-3-LINKNOTUP: Link 0 in linkset 2-463_RMSGW1 failed. Reason=communication lost
b.1) For M2PA based links, obtain "show cs7 m2pa sctp parameters <linkset><slc>", and search "Num retrans:" and "Num times failed:" from the output. Please note that if the association is not established, theremight be no output at all. Also check the command "show cs7 m2pa sctp statistics <linkset> <slc>"
b.2) For XUA based links, use the following commands to getcorresponding information:
- "show cs7 asp | in <asp name>" to get the association id for this ASP.
- "show ip sctpassociation parameters <assoc id>"
c) Check the output of "show ip route <remote ip>" command, and find theinterface being used for the remote ip, like the example below:
7613#show ip route 192.168.70.242
Routing entry for 192.168.70.0/24
Known via "connected", distance 0, metric 0 (connected, via interface)
Routing Descriptor Blocks:
* directly connected, via FastEthernet1/0/1
Route metric is 0, traffic share count is 1
d) Check the "show interfaces <interface>" command, to see if there is any packet drops or flushes.
e) If no packet drops and flushes found in the output of "show interfaces", then capture Ethereal trace for 5-10 minutes while linkflapping is observed and open a Cisco TAC case for further help.
Hope that the above helps when observing the mentioned link flapping issues.
Kind regards,
Samuel.
