Simultaneous Ring Not Working with SBC

[Peter Krautle]

Our simultaneous ring feature is no longer working after upgrading our production server and moving it to a new data center. Sipxcom is at 21.04 and is running under Vmware Esxi release 7.0. Other than minor dialplan and SIP profile changes to the SBC that point to the new public IPs at the new data center, there have been no changes to the Sangoma SBC. The setup of Sipxcom with the SBC is described in step 3 of this wiki page https://wiki.ezuce.com/display/sipXcom/Sangoma+SBC+Interoperability+with+Sipxcom+High+Availability.

Thinking that the backup/restore procedures used to build the new production server might be an issue, a new Sipxcom test server was configured (10.20.6.40) and a test SBC (10.20.2.18) was configured - same results.  The Sipxcom server profiles was issue and Sipxcom server was restarted. Packet trace is here and was taken from the SBC. There are 3 legs to call:

- Incoming call from the ITSP to the SBC.

- Incoming call from the SBC to Sipxcom and simultaneous ring back to the SBC.

- Outgoing simultaneous ring from the SBC to the ITSP.

When one inspects the incoming call from the SBC to Sipxcom https://www.dropbox.com/s/iufpcz602rn2k57/SimultaneousRingissue.pcap?dl=0, you see the invite from the SBC to 9144172295 issued correctly, but when one inspects the INVITE back to the SBC, the SDP points to the 10.20.2.18 SBC address instead of the expected 10.20.6.40 address.  The signaling for the simultaneous ring works correctly but there is no bearer path.

Does anyone have any ideas on how to force the simultaneous ring INVITE from Sipxcom to use the Sipxcom IP address (10.20.6.40) instead of SBC IP (10.20.2.18) - I am out of ideas on nex steps :(. Many thanks in advance. Peter

[Peter Krautle]

I built a new lab SBC (10.20.2.18) and Sipxcom 21.04 voice server (10.20.2.50) and tested simultaneous ring. Issue remains - signaling works but there is no bearer path when the call is answered on a mobile phone. There are two PCAPs on dropbox - one taken at the SBC  https://www.dropbox.com/s/c76wgj1p814tboe/SBCPacketCapture.pcap?dl=0 and Sipxcom https://www.dropbox.com/s/9rxk8emdkxk0lgz/VoiceserverPacketCapture.pcap?dl=0. Call flow is as follows:

• Incoming call from 914-417-2275 into the test SBC and Sipxcom at 9144172295. Extension 200 is mapped to 9144172295.
• Call forward on x200 programmed to simultaneously my mobile at 551-286-0862.
• There is a screen scrape of the problem packet here https://www.dropbox.com/s/1fisybnnzwo5e9l/InviteofSimulRing.pptx?dl=0 (there may be others). What is happening is that Sipxcom is sending the INVITE to my mobile using the SDP of the SBC (10.20.2.18) instead of Sipxcom IP address (10.20.2.50).

This has been working for 3-4 years without issue. We  made three recent changes - the physical server was upgraded, Vmware Esxi was upgraded from 6.7 to 7.0 Update 3, and the server was moved to a new data center, requiring new public IP addresses to be defined in the SBC. A ticket is open with Sangoma technical support, but any insights are appreciated. I'm probably missing something very obvious. All the best Peter

[Todd Hodgen]

Peter,  Is there a subnet that needs to be defined in Internet Domains under Internet Calling.   Just a guess……

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[Peter Krautle]

Many thanks for the feedback - much appreciated. I just post these PCAPS from another client - think the Vmware 6.7 to 7.0 upgrade may be part of the issue. I just posted these PCAPs Sipcom https://www.dropbox.com/s/4aeo1uit1qbon26/WorkingSimulringvoiceserver.pcap?dl=0 and SBC https://www.dropbox.com/s/4aeo1uit1qbon26/WorkingSimulringvoiceserver.pcap?dl=0 where simultaneous ring works correctly. I'll be doing a stare/compare tomorrow of these PCAPs, and will keep you updated.

All the best

Peter

[Peter Krautle]

Got to the bottom of the simultaneous ring issue. Esxi6.7/7.0 upgrade had nothing to do with the problem. When we moved the server to a new data center, the SBC had be programmed with new external public IP addresses on where to send the RTP traffic - normalcalls worked correctly. The first digits of the public IP address were specified incorrectly (71 instead of 74) - it took me several days to find this fat finger issue. Senior moment :( Peter

[Todd Hodgen]

I hate things like this.  Makes me wonder why I still continue to think I should be doing this type of work......

sent using my two left twiddling thumbs

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From: sipxco...@googlegroups.com <sipxco...@googlegroups.com> on behalf of Peter Krautle <pmkr...@gmail.com>
Sent: Tuesday, November 29, 2022 2:53:51 PM
To: sipxcom-users <sipxco...@googlegroups.com>
Subject: Re: [sipxcom-users] Re: Simultaneous Ring Not Working with SBC

 

To view this discussion on the web visit https://groups.google.com/d/msgid/sipxcom-users/258e0985-9466-4067-9008-9f07268f8f3dn%40googlegroups.com.