atcomsystems.ca/forum Forums TDM Business Telephone Systems NEC Telephones & Systems SV9100 SIP Trunk Issue

We are having an issue with a client intermittently cannot make calls out. Ran wireshark and according to the carrier on failed calls the 9100 keeps sending invites without the Digest Authentication Information. On calls that work it does. Has anyone had these issues. Carrier is NetCarrier and they use there own open source switch.

Couple things. Make sure if you are sending CID they are all correct and the carrier is correct. Make sure all your profiles are set to the same one for that carrier. Otherwise, you might want to get NTAC involved. Anytime I hear someone using "their own open source" system I get a little dubious. Sometimes session border controllers or firewalls can get in the way.

Coral Tech thanks for the feedback. We did get NTAC involved sent them the database and wireshark captures. We use this carrier for many other 8100 clients and on our in house 8100 for our SIP trunks for 4 years now and have not had this issue. The Profiles are all set to 1 and the Carrier is set to B as it is on our 8100. Hopefully we will here something from NTAC. The wireshark captures were taken right at the system so the invites were coming out of the system without the authentication information on failed calls. Here is the other thing we found out we can duplicate the issue every time when another user makes and outbound call, the call goes through and they are on the phone, a second user goes to make a call and the call fails. However we can dial inbound with no issues while not being able to dial out.

That almost sounds like a provisioning issue. Is the call getting a reject from the provider? The fact you can duplicate it makes it a hell of a lot easier to troubleshoot.

You know, thinking about this you might want to look at the router forwarding. Make sure the UDP port range is opened up I think 10020-10531 to the media gateway IP address of the system. And of course 5060 etc to the signalling address.

Update - all port forwarding is set for the DSP and 5060. Here is what NTAC is stating.
I also attached this to the IR as well. The issue in the bad calls is that we are getting invalid Via headers in the carriers 100 trying and 401 unauthorized response to our request to Invite.

You will notice in this example that the good calls these packets contain a “Sent By Port” field, and in the bad call this field is missing.

Because these are invalid Via headers the system will not respond.

Please update the IR if you have any further questions.

So like tennis it is back in the Carrier's court.

The entire weird thing about this is it only appears to be happening after a user makes and outbound call, stays on that call and a second user goes to make an external call. That is when the call fails. However calls into the system work no problem during that time frame, as well as multiple calls in. As soon as the first user hangs up you can make a call out.

Good luck. I've seen many games of tennis played with 2nd and 3rd level SIP carriers over the past few years. Some will even do a software update overnite and then deny that they caused the problems..

Surprise Surprise the Carried did have SIP ALG enabled on their managed router. Which is what I asked two weeks ago when the problem first came up and sent them the Wireshark Captures indicating that it might be enabled.

Glad you sorted it eventually ..