While testing some outbound T.38 fax calls, they were getting quickly disconnected, and I found that I was running into problems related to the session timer during the re-invite process. I was wondering if anyone else has run into anything similar? I'm not sure if it's just T.38 related, or would have occurred on any re-invite scenario. In the trace below, I think my gateway (Flowroute) reacts a little strangely since it appears to refuse a session timer that it itself chose during the initial invite process (instead seeming to want to flip who handles the refresh), but while odd, that's not necessarily invalid, is it? I also noticed that FreeSWITCH promoted the timer to a requirement during the re-invite. But the eventual call disconnect seems due to FreeSWITCH never completing renegotiation - the last thing it transmits is a 100 response. Disabling session timers (enable-timer=false) in the profile gets around the problem, but it seems like keeping the timers, if possible, is preferable in terms of an additional safety net. Any thoughts or suggestions would be welcome. Does this appear strictly a gateway side issue, or is something also not working properly on the FreeSWITCH side? -- David Note: git-b1d1beb is the same as f1de377 from 7/16 plus one local change to mod_conference. The dialed number has been replaced by 11111111111, my public switch address with 111.111.111.111, and I've excluded the Proxy-Authorization header throughout. The initial call setup seems ok: - - - - - - - - - - - - - - - - - - - - - - - - - send 1390 bytes to udp/[216.115.69.144]:5060 at 21:29:19.155730: ------------------------------------------------------------------------ INVITE sip:11111111111@sip.flowroute.com SIP/2.0 Via: SIP/2.0/UDP 111.111.111.111:5080;rport;branch=z9hG4bKK8mr3pcre4a2j Max-Forwards: 70 From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com> Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349016 INVITE Contact: <sip:gw+flowroute@111.111.111.111:5080;transport=udp;gw=flowroute> Expires: 600 User-Agent: FreeSWITCH-mod_sofia/1.0.head-git-b1d1beb 2011-07-18 23-08-16 -0400 Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, UPDATE, INFO, REGISTER, REFER, NOTIFY Supported: timer, precondition, path, replaces Allow-Events: talk, hold, refer Content-Type: application/sdp Content-Disposition: session Content-Length: 213 X-FS-Support: update_display Remote-Party-ID: <sip:0000000000@sip.flowroute.com>;party=calling;screen=yes;privacy=off v=0 o=FreeSWITCH 1311342219 1311342220 IN IP4 111.111.111.111 s=FreeSWITCH c=IN IP4 111.111.111.111 t=0 0 m=audio 27940 RTP/AVP 9 0 8 3 101 13 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ptime:20 ------------------------------------------------------------------------ recv 305 bytes from udp/[216.115.69.144]:5060 at 21:29:19.194573: ------------------------------------------------------------------------ SIP/2.0 100 Trying Via: SIP/2.0/UDP 111.111.111.111:5080;rport=5080;branch=z9hG4bKK8mr3pcre4a2j From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com> Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349016 INVITE Content-Length: 0 ------------------------------------------------------------------------ recv 687 bytes from udp/[216.115.69.144]:5060 at 21:29:19.839258: ------------------------------------------------------------------------ SIP/2.0 180 Ringing From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821 Via: SIP/2.0/UDP 111.111.111.111:5080;rport=5080;branch=z9hG4bKK8mr3pcre4a2j Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349016 INVITE Record-Route: <sip:216.115.69.133;lr> Record-Route: <sip:216.115.69.144;lr> Contact: <sip:+11111111111@67.16.125.60:5060;transport=udp> Content-Length: 184 Content-Type: application/sdp v=0 o=- 3829 19246 IN IP4 67.16.125.60 s=- c=IN IP4 67.16.125.60 t=0 0 m=audio 50330 RTP/AVP 0 101 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 a=ptime:20 a=maxptime:20 ------------------------------------------------------------------------ recv 850 bytes from udp/[216.115.69.144]:5060 at 21:29:21.587130: ------------------------------------------------------------------------ SIP/2.0 200 OK From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821 Via: SIP/2.0/UDP 111.111.111.111:5080;rport=5080;branch=z9hG4bKK8mr3pcre4a2j Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349016 INVITE Record-Route: <sip:216.115.69.133;lr> Record-Route: <sip:216.115.69.144;lr> Accept: application/sdp, application/isup, application/dtmf, application/dtmf-relay, multipart/mixed Contact: <sip:+11111111111@67.16.125.60:5060;transport=udp> Supported: timer,replaces Session-Expires: 10800;refresher=uas Content-Length: 184 Content-Type: application/sdp v=0 o=- 3829 19246 IN IP4 67.16.125.60 s=- c=IN IP4 67.16.125.60 t=0 0 m=audio 50330 RTP/AVP 0 101 a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-15 a=ptime:20 a=maxptime:20 ------------------------------------------------------------------------ send 826 bytes to udp/[216.115.69.144]:5060 at 21:29:21.587678: ------------------------------------------------------------------------ ACK sip:+11111111111@67.16.125.60:5060;transport=udp SIP/2.0 Via: SIP/2.0/UDP 111.111.111.111:5080;rport;branch=z9hG4bKmHeH5HXUBD1me Route: <sip:216.115.69.144;lr> Route: <sip:216.115.69.133;lr> Max-Forwards: 70 From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821 Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349016 ACK Contact: <sip:gw+flowroute@111.111.111.111:5080;transport=udp;gw=flowroute> Content-Length: 0 ------------------------------------------------------------------------ - - - - - - - - - - - - - - - - - - - - - - - - - The gateway appears to have specified a uas-refreshed session timer in its 200 message. Below, the re-invite happens for T.38. Here I noticed the new Require: timer option (with the session-expires from before), which is rejected, then oddly the gateway re-invites but apparently with a uac-refreshed timer. FreeSWITCH then sends a 100, and nothing else. - - - - - - - - - - - - - - - - - - - - - - - - - send 1638 bytes to udp/[216.115.69.144]:5060 at 21:29:22.108341: ------------------------------------------------------------------------ INVITE sip:+11111111111@67.16.125.60:5060;transport=udp SIP/2.0 Via: SIP/2.0/UDP 111.111.111.111:5080;rport;branch=z9hG4bKNt796ceZ8NQ7S Route: <sip:216.115.69.144;lr> Route: <sip:216.115.69.133;lr> Max-Forwards: 70 From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821 Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349017 INVITE Contact: <sip:gw+flowroute@111.111.111.111:5080;transport=udp;gw=flowroute> User-Agent: FreeSWITCH-mod_sofia/1.0.head-git-b1d1beb 2011-07-18 23-08-16 -0400 Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, UPDATE, INFO, REGISTER, REFER, NOTIFY Require: timer Supported: timer, precondition, path, replaces Session-Expires: 10800;refresher=uas Min-SE: 120 Content-Type: application/sdp Content-Disposition: session Content-Length: 322 X-FS-Support: update_display Remote-Party-ID: <sip:0000000000@sip.flowroute.com>;party=calling;screen=yes;privacy=off v=0 o=FreeSWITCH 1311342219 1311342221 IN IP4 111.111.111.111 s=FreeSWITCH c=IN IP4 111.111.111.111 t=0 0 m=image 27940 udptl t38 a=T38FaxVersion:0 a=T38MaxBitRate:14400 a=T38FaxFillBitRemoval a=T38FaxRateManagement:transferredTCF a=T38FaxMaxBuffer:2000 a=T38FaxMaxDatagram:400 a=T38FaxUdpEC:t38UDPRedundancy ------------------------------------------------------------------------ recv 330 bytes from udp/[216.115.69.144]:5060 at 21:29:22.147343: ------------------------------------------------------------------------ SIP/2.0 100 Trying Via: SIP/2.0/UDP 111.111.111.111:5080;rport=5080;branch=z9hG4bKNt796ceZ8NQ7S From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821 Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349017 INVITE Content-Length: 0 ------------------------------------------------------------------------ recv 338 bytes from udp/[216.115.69.144]:5060 at 21:29:22.170802: ------------------------------------------------------------------------ SIP/2.0 420 Bad Extension From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821 Via: SIP/2.0/UDP 111.111.111.111:5080;rport=5080;branch=z9hG4bKNt796ceZ8NQ7S Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349017 INVITE Unsupported: timer ------------------------------------------------------------------------ send 446 bytes to udp/[216.115.69.144]:5060 at 21:29:22.171034: ------------------------------------------------------------------------ ACK sip:+11111111111@67.16.125.60:5060;transport=udp SIP/2.0 Via: SIP/2.0/UDP 111.111.111.111:5080;rport;branch=z9hG4bKNt796ceZ8NQ7S Route: <sip:216.115.69.144;lr> Route: <sip:216.115.69.133;lr> Max-Forwards: 70 From: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS To: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821 Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 15349017 ACK Content-Length: 0 ------------------------------------------------------------------------ recv 1160 bytes from udp/[216.115.69.144]:5060 at 21:29:26.533911: ------------------------------------------------------------------------ INVITE sip:gw+flowroute@111.111.111.111:5080;transport=udp;gw=flowroute SIP/2.0 Record-Route: <sip:216.115.69.144;lr> Record-Route: <sip:216.115.69.133;lr> From: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821;tag=SDvtmh399-gK0a9c4821 To: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS Via: SIP/2.0/UDP 216.115.69.144;branch=z9hG4bK1dbe.2add7494aaa097ffa4b75892aba82f61.0 Via: SIP/2.0/UDP 216.115.69.133;branch=z9hG4bK1dbe.bbcd1cf6f99ecd7a297b5dc33dd676dd.0 Via: SIP/2.0/UDP 67.16.125.60:5060;branch=z9hG4bKmthalp308g505g83r340sb0000hc3.1 Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 4313 INVITE Max-Forwards: 67 Accept: application/sdp, application/isup, application/dtmf, application/dtmf-relay, multipart/mixed Contact: <sip:+11111111111@67.16.125.60:5060;transport=udp> Supported: timer,replaces Session-Expires: 10800;refresher=uac Min-SE: 90 Content-Length: 172 Content-Type: application/sdp v=0 o=- 3829 19247 IN IP4 67.16.125.60 s=- c=IN IP4 67.16.125.60 t=0 0 m=image 50330 udptl t38 a=T38FaxRateManagement:transferredTCF a=T38FaxUdpEC:t38UDPRedundancy ------------------------------------------------------------------------ send 688 bytes to udp/[216.115.69.144]:5060 at 21:29:26.534587: ------------------------------------------------------------------------ SIP/2.0 100 Trying Via: SIP/2.0/UDP 216.115.69.144;branch=z9hG4bK1dbe.2add7494aaa097ffa4b75892aba82f61.0 Via: SIP/2.0/UDP 216.115.69.133;branch=z9hG4bK1dbe.bbcd1cf6f99ecd7a297b5dc33dd676dd.0 Via: SIP/2.0/UDP 67.16.125.60:5060;branch=z9hG4bKmthalp308g505g83r340sb0000hc3.1 Record-Route: <sip:216.115.69.144;lr> Record-Route: <sip:216.115.69.133;lr> From: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821;tag=SDvtmh399-gK0a9c4821 To: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 4313 INVITE User-Agent: FreeSWITCH-mod_sofia/1.0.head-git-b1d1beb 2011-07-18 23-08-16 -0400 Content-Length: 0 ------------------------------------------------------------------------ - - - - - - - - - - - - - - - - - - - - - - - - - At this point the fax actually proceeds for a few seconds, but I get a BYE after about 10 seconds: - - - - - - - - - - - - - - - - - - - - - - - - - recv 708 bytes from udp/[216.115.69.144]:5060 at 21:29:36.285179: ------------------------------------------------------------------------ BYE sip:gw+flowroute@111.111.111.111:5080;transport=udp;gw=flowroute SIP/2.0 Record-Route: <sip:216.115.69.144;lr> Record-Route: <sip:216.115.69.133;lr> From: <sip:11111111111@sip.flowroute.com>;tag=SDvtmh399-gK0a9c4821;tag=SDvtmh399-gK0a9c4821 To: "" <sip:XXXX@sip.flowroute.com;transport=udp>;tag=KcKN11gj6arQS Via: SIP/2.0/UDP 216.115.69.144;branch=z9hG4bKecbe.d96adce16997b042396d38106987a638.0 Via: SIP/2.0/UDP 216.115.69.133;branch=z9hG4bKecbe.75fcc1a3bc1f3a68e4c0241e8b6b0298.0 Via: SIP/2.0/UDP 67.16.125.60:5060;branch=z9hG4bKmthalp308g505g83r340sd00001d3.1 Call-ID: 7fe743c9-2f4c-122f-9790-f23c91931894 CSeq: 4314 BYE Max-Forwards: 67 Content-Length: 0 ------------------------------------------------------------------------ - - - - - - - - - - - - - - - - - - - - - - - - -