SOLVED: Call drops after 30 sec on hold - no hardware

[Bob Denny]

I have a mystery... here's the setup:

Bria -> CallCentric -> 3CX -> Bria

The first Bria (a softphone by CounterPath) calls sip:[email protected] which is the SIP URI of the second phone (which is an extension on the 3CX switch). The call completes fine. Then the second Bria puts the call on hold, and the 3CX switch starts playing hold music, which can be heard on the first Bria. 30 sec later the call drops.

I searched the forums here, and the existing threads talk about silence detection settings on VOIP gateways, etc. I have no hardware involved, so the only way to fix this would be with a setting on the Bria softphone or the 3CX switch. I've crossposted to the Bria forum too.

 

[Bob Denny]

Re: Call drops after 30 sec on hold - no hardware

Even more strangeness with a PSTN call into my DID number:

PSTN -> DID -> CallCentric -> 3CX -> Bria

If the Bria puts the PSTN caller on hold no hold music can be heard and again the call drops after 30 sec on hold. In the previous scenario, at least the hold music could be heard by the caller.

Now I have 2 questions. If you want I can post the one regarding "no hold music for PSTN -> DID" in a separate thread...

 

[igor.snezhko]

Re: Call drops after 30 sec on hold - no hardware

Do you use Dlink ADSL modem?

 

[Bob Denny]

Re: Call drops after 30 sec on hold - no hardware

No, no hardware at all. Hence the title 8) It's all software even the phones (the Bria softphone).

 

[SY]

Re: Call drops after 30 sec on hold - no hardware

No, no hardware at all. Hence the title 8) It's all software even the phones (the Bria softphone).

Bob,

try to bind the extension (which is handled by Bria) to media server (tick "PBX delivers audio"). It should help.

 

[Bob Denny]

Stepan --

Thanks for the suggestion! I tried that but it didn't help. However, I just solved both problems by changing VOIP Provider, Advanced tab, Provider Details settings:

• Supports Re-invite -> OFF
  Supports Replace -> OFF

After these two changes, the hold music is heard by external callers coming in through CallCentric, and the 30 sec call-drop is no longer a problem.

I must say, I am so impressed with the 3CX switch. As I get experience and eventually make it a mission-critical part of my business, I'll buy a license. You guys definitely deserve it.

 

[Bob Denny]

Update: I was browsing the Technical Docs at http://wiki.3cx.com/Home/technical-documentation-dash/media-server and discovered that turning off Re-Invite forces the switch into Transcode mode just like PBX Delivers Audio. I must have made a mistake when I tested your solution, I apologize.

I don't want transcoding for every call I make to CallCentric. I need to find out why I have these problems with Supports-Reinvite turned on (and the other two turned off). Time for my network sniffer and help from CallCentric.

Thanks again for pointing me in the right direction.

 

[archie]

Transcode only kicks in when necessary, i.e. parties have negotiated different codecs. Otherwise we will just proxy RTP stream (i.e. receive it on media server and than send to other party without any change).
Note, that if you want to have music on hold for endpoint that doesn't really understand re-INVITE (and Callcentric is the case as I see) - you are bound to bind to media server. Otherwise PBX is forced to issue re-INVITE.

 

[SY]

Update: I was browsing the Technical Docs at http://wiki.3cx.com/Home/technical-documentation-dash/media-server and discovered that turning off Re-Invite forces the switch into Transcode mode just like PBX Delivers Audio. I must have made a mistake when I tested your solution, I apologize.

I don't want transcoding for every call I make to CallCentric. I need to find out why I have these problems with Supports-Reinvite turned on (and the other two turned off). Time for my network sniffer and help from CallCentric.

Thanks again for pointing me in the right direction.

Why don't you want transcoding?

 

[Bob Denny]

I don't want transcoding because I think it limits the call quality negotiation to the (small set) of codecs that 3CX supports. Perhaps that's wrong?

Related question: Can I add to the set of codecs? My SIP phone (CounterPath Bria) has many more.