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Standard User farrinaf
(newbie) Sat 14-Nov-20 14:04:46
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Incoming VOIP call drops every 15 minutes


[link to this post]
 
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 ?
Standard User Ancient_Mariner
(eat-sleep-adslguide) Sat 14-Nov-20 23:25:27
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
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!

Clive

Andrews & Arnold Home::1 FTTC DrayTek Vigor 2762ac Cisco SPA112 and HUAWEI E5776 with O2 Data SIM
Standard User E300
(member) Sun 15-Nov-20 09:20:37
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
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.


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Standard User jpm
(member) Sun 15-Nov-20 12:55:24
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
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.
Standard User jchamier
(eat-sleep-adslguide) Sun 15-Nov-20 14:28:34
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
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?

21 years of broadband connectivity since 1999 trial - Live BQM
Standard User kitcat
(experienced) Sun 15-Nov-20 14:47:44
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
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.
Standard User MHC
(sensei) Sun 15-Nov-20 16:16:13
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
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 ...


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

M H C


taurus excreta cerebrum vincit
Standard User farrinaf
(newbie) Mon 16-Nov-20 09:00:15
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Re: Incoming VOIP call drops every 15 minutes


[re: jchamier] [link to this post]
 
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
Standard User farrinaf
(newbie) Mon 16-Nov-20 09:06:43
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Re: Incoming VOIP call drops every 15 minutes


[re: jpm] [link to this post]
 
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
Standard User farrinaf
(newbie) Tue 08-Dec-20 10:09:47
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
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
Standard User jpm
(member) Tue 08-Dec-20 10:47:58
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
Hard to tell as the capture doesn't have the SIP messaging in, not sure if that was filtered out or if it just wasn't appearing.

Is there something called NAT refresh time in the Gigaset settings?
Standard User farrinaf
(newbie) Tue 08-Dec-20 12:11:26
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Re: Incoming VOIP call drops every 15 minutes


[re: jpm] [link to this post]
 
Thank you for your interest (and prompt attention).

I have reviewed the Gigaset configuration screens but can see no mention of anything NAT related.

It is strange that there is no SIP traffic showing in my original trace. As I am not immediately in a position to undertake a further "Talk Talk" capture, by way of an experiment I tried ringing my VOIP landline from my mobile whilst initiating a capture in the form previously advised.

This later capture clearly shows a SIP/SDP invite request with my mobile number and AAISP VOIP user name visible, as well as the disconnect instruction upon termination, so it would appear to be correctly configured.

I think the only logical way forward it to once again try a "new" capture, this time with a longer pre/post capture period (unfortunately with inevitable further delay)

Edited by farrinaf (Tue 08-Dec-20 12:12:16)

Standard User kitcat
(experienced) Tue 08-Dec-20 14:38:40
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
farrinaf

On your mobile calls you should see at the start a SP invite and an ack, etc.

It sounds like on talktalk one That the call is just dropping at the talktalk end with no SP cleardown.

If you get the trace at the start it may show that TalkTalk is not ack the SIP setup so it just times out at 15 min and drops the call ( not a call disconnect). The 15min is just the set time if it doesn't see a response.

It can also be that the TDM-IP gateway somewhere has not been setup correctly to pass the correct C7 signal back to the TDM which will lead the TDM switch to time the call out after the set period (15 min) . In which case the SIP will again not show anything for the disconnect..

I believe the 2nd is the most likely BUT this makes it almost impossible to put right unless you know a technical person dealing with the TDM-SIP gateways that TalkTalk are passing through.

(We used to see the max call length truncated from what would be expected if something like this had happened BUT had to be looking at each gateway to be aware of it and only a nerd like me ever looked to see why different gateways had different call characteristics.)
.
Standard User farrinaf
(newbie) Thu 10-Dec-20 14:34:01
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Re: Incoming VOIP call drops every 15 minutes


[re: kitcat] [link to this post]
 
In reply to a post by kitcat:
farrinaf

It sounds like on talktalk one That the call is just dropping at the talktalk end with no SP cleardown.

If you get the trace at the start it may show that TalkTalk is not ack the SIP setup so it just times out at 15 min and drops the call ( not a call disconnect). The 15min is just the set time if it doesn't see a response.

Thanks for the input - I shall, as per your suggestion, arrange to packet capture the start of the call.

My "Talk Talk" subscriber is not a frequent caller (he's a 91 year old friend, so I have to go at his pace not mine!) so there may be a further delay before I come back to the forum.

Cheers

Edited by farrinaf (Thu 10-Dec-20 14:34:28)

Standard User farrinaf
(newbie) Sat 19-Dec-20 16:19:45
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
Okay I now have a packet capture I initiated (by prior arrangement) a couple of seconds prior to my friend initiating a call to my VOIP line from his Talk Talk land line with my capture terminating shortly thereafter.

I have also taken the opportunity to freshly capture what happened at 15 minutes (not same segment as initiation capture) when the call apparently drops.

Packet capture an be viewed on Google Drive here

His line is Ex Directory so his telephone number is not shown (although my test VOIP line number is!).

As far as I can ascertain beyond my test VOIP number there is no other particularly confidential information disclosed - if anyone spots anything buried within the data that may be, I would be obliged if they would let me known and I shall remove the capture from public view and make it available upon request on a named basis.

Looking at the actual data I believe I can see a SIP ACK at line 16 but this seems to be coming from AAISP (81.187.38.118) – I wonder if I need to chase them to see if their logs shown anything back to Talk Talk.

I suppose the other unknown (to me at least) is how Talk Talk calls are routed to AAISP
Standard User kitcat
(experienced) Sat 19-Dec-20 20:41:12
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Re: Incoming VOIP call drops every 15 minutes


[re: farrinaf] [link to this post]
 
farrinaf
Initiation
The Ack is on line 84.CSeq: 1 ACK

Line 2066 sets a timer expiry of 600 seconds this should repeat every 10 600 sec. ( 2052 offers 180 seconds)

15 min term

has another expiry of 600 seconds on line 71

Note on line 56 the other end keeps offering 180 sec

I can see no BYE in either file ( there is a bye in the initiation file at line 2073 but not a SIP message.)

five 180 offers would be your 15 min. Just wondering if TT end is not recognising your 600 second response

I still think the TalkTalk end is tearing it down without sending a BYE due to a timeout somewhere.

Simple SIP tutorial but doesn't cover this variant very well.
Standard User farrinaf
(newbie) Mon 21-Dec-20 09:40:40
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Re: Incoming VOIP call drops every 15 minutes


[re: kitcat] [link to this post]
 
Kitcat

Thanks for taking the time to respond (so promptly as well) and for the further information therein.

Will investigate further and review the article you kindly linked to.

Cheers
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