CICs in Reset

Owned by Kelli Higdon
Last updated: Mar 18, 2024
3 min read

When your CIC's are in a reset state the best idea is to run a trace on the signalling link. To run a trace go to Wireshark Tracing - PCAP and you will see the command to use is "wanpipemon -i w1g1 -pcap -pcap_file mtp2.pcap -mtp2-msu -prot MTP2 -full -systime -c trd". You can adjust this command for the interface your signalling link is on. Also keep in mind you need to run this on all signalling links with in the link set to capture all frames; so multiple traces may be required. 

To preform the trace best idea is stop NSG using the command "/etc/init.d/nsg stop" from the Linux command line. Then start all wireshark traces then start NSG using the command "/etc/init.d/nsg start". This will cause the traces to have all messages sent/received when NSG is starting up. So wait a few minutes and insure the cics stay in reset. Once this is done stop the trace. 

Below is traces and info from a system I have recently seen issues with. 

SPC: 1021
APC/DPC: 1000

Best idea is download the wireshark above so you can see how this issue was resolved. So the first step was I simply found a message for a cic that was in reset. In this case it was cic #1. So once the message was found I simply expanded the "ISDN USER Part" and right click on "CIC" then go to "apply as filter -> selected". This will then show you only messages for cic #1. 

Once the filter was applied it is clear the telco is sending back a "UCIC" which wireshark shows means "unequipped CIC". So from this we can see the telco is not allowing the cic to come up. So we could contact the telco at this point and ask them about this. Also in most cases the telco simply just does not reply at all. So in that case take the wireshark to the telco and the telco will look into why they are not responding to our RSC messages. In this case I went one step further; see below. 

Next what I did was simply enable a filter to see any messages coming from the telco, below is how I did that. 

Next I simply looked through the filtered messages and found the telco was sending us many cic resets "RSC" starting with cic 195. So I simply changed the cic base from 1 to 195 and the issue was resolved. All cic's came up and calls were working. Below is the wireshark showing how I found that. 

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