Incoming VOIP call drops every 15 minutes

Bit of a strange one (well to me at least!)

I am using a Gigaset N300A IP with a VOIP line provided by AAISP. This is used purely to receive incoming calls (is being used as a test prior to the migration of my existing PlusNet landline when I move from their FTTC (80/20) to a fully FTTP connection (Zen 100/20). As an aside will be running both FTTC & FTTP simultaneously with intention that former will be automatically ceased when I port the associated number to AAISP

As a gateway device I am operating a pfsense firewall and have succesfully configured it to talk to AAISP. Everything appeared to work just fine (in fact the line quality if anything appeared better than my existing copper land line).

A number of friends have called me using various providers, all with absolutely no problem, that is until a friend whose telephone provider is Talk Talk rang (note NOT VOIP)

Bizarrley to the absolute second every 15 minutes the line drops. He can immediately rediall and it rings at my end and we carry on where we left off. BT/PlusNet and mobile calls appear to be unaffected, only this TT line.

I am minded to think that if is probably some form of over aggressive line monitoring at the TT end assuming that the line has dropped (or the connected call is not showing any data passing).

Given that it only happens with TT I don't think this is a malfunctioning SIP session timer, but I was wondering if anyone else had come across any issues with TT ?

Just an idea, do you know of any other TT users who could call you and see if they have any similar problems? Also, if your TT friend calls you on your copper landline, any 15 minute problem? This to check whether there is an issue with his TT line.

Cheers!

One thing to check, if you add logging to the default Deny Rule (think it is on by default) in the pfSense firewall, then immediately after the call has dropped, head over to Status > System Log > Firewall and see if you have any blocked traffic from AAISP VoIP addresses. If Yes that would indicate your firewall is suddenly deciding to drop traffic, if nothing shows up here it would suggest your theory that TT are dropping the call for some reason.

Packet capture the SIP traffic (assuming AAISP don't use secure SIP) and see what the message that ends the call is. If you're getting a 'bye' from the far side then take that capture to AAISP.

In reply to a post by farrinaf:

As an aside will be running both FTTC & FTTP simultaneously with intention that former will be automatically ceased when I port the associated number to AAISP

I can confirm that moving the number to AAISP VoIP will cease your FTTC & landline service from Plusnet as I did exactly this (but I moved to Virgin Media).

I cannot help on your 15 minute issue, but have you asked AAISP tech support to investigate?

farrinaf

It sounds as if the Talktalk calling customer is not recognising the VOIP called answer signal and is therefore timing out after it's set period, eg 15 min.

If so this is a Talktalk issue and nothing to do with your set up.

This could be due to the way Talktalk are routing the call to the VOIP network, a specific TDM-VIOP gateway being faulty that this customer always uses. or a generic within Talktalk.

Do you know another talktalk TDM customer to try and see if that replicates the issue , if so it is a generic within talktalk.

I had a similar issue with BTs VoIP service and only when called/calling some numbers. I used a BT adapter not an N300 at that time and BT never got to the bottom of it. Then suddenly it disappeared after living with it for months. It has to be soemwhere in te signalling - but where ...

In reply to a post by jchamier:

I can confirm that moving the number to AAISP VoIP will cease your FTTC & landline service from Plusnet as I did exactly this (but I moved to Virgin Media).

This is good to hear so hopefully exiting PlusNet (famous last words!) should be seemless

Thanks to all for the many helpful suggestions and observations

Its good to hear that this is not an unknown problem, albeit if the issue is at Talk Talk I am not going to be holding my breath waiting for them to resolve it.

Unfortunately I don't know anybody else who is mad enough to use Talk Talk (with apologies to any TT subscribers reading this!).

The clear way forward would appear to be packet capture of the SIP data and a quick play with the inbuilt packet capture on pfsense shows the packets to be unencrypted.

I'll update this post once I have more information (may be a while)

Cheers

Sorry for the delay in updating this tread.

I have now undertaken a packet capture via my firewall covering a period of approximately 10 seconds prior to the 15 minute timer with capture terminating shortly thereafter when the VOIP call dropped. To set the scene I configured my firewall to packet capture all traffic on my LAN interface from IP address 192.168.123.160 (My Gigaset N300A)

To be honest (to my untutored eye) the capture shows nothing beyond the connection between my Gigaset device and AAISP (81.187.30.118) still seems to be running.

On the off chance those more learned than me might want to take a look, the capture can be downloaded from the link below (note this link will ultimately be removed, so if you are viewing this thread some weeks after posting it may no longer be live).

I wonder if the next step might be inviting AAISP to view their logs ie their connection to incoming call from Talk Talk to see if the drop occurs at their (AAISP) servers

Google Drive Download Packet Capture