Hello,

I currently use Freeswitch 1.6.8-1 in production, and have some ISDN gateways sending SDP including T.38 for voice calls (not faxes). Calls are handled without problems by freeswitch.

I have another platform, with freeswitch 1.6.19 and same configuration.
However, voice calls received with SDP including t.38 are rejected with 488 INCOMPATIBLE_DESTINATION :
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:4028 sofia/internal_1/33183817938@gv-ics-prd-301 T38 REFUSE on request
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [NOTICE] sofia.c:7566 Hangup sofia/internal_1/33183817938@gv-ics-prd-301 [CS_NEW] [INCOMPATIBLE_DESTINATION]

I didn't find any valid configuration to make those calls accepted, except configuring proxy_media, which I don't want to use.

Is this behaviour a "normal" behaviour ? Could it be a bug ?
This is a very big issue for us ...


Here is the log extract :

recv 1391 bytes from udp/[10.9.30.152]:5060 at 23:47:39.443941:
   ------------------------------------------------------------------------
   INVITE sip:0170993660@10.9.30.188:5060 SIP/2.0
   Record-Route: <sip:10.9.30.152;lr=on>
   Record-Route: <sip:10.3.1.220;lr=on>
   Via: SIP/2.0/UDP 10.9.30.152;branch=z9hG4bK51d.d7e922c4.0
   Via: SIP/2.0/UDP 10.3.1.220;branch=z9hG4bK51d.ba6f34d1.0
   Via: SIP/2.0/UDP 10.3.1.231;branch=z9hG4bKac1339541470
   Max-Forwards: 68
   From: <sip:33183817938@gv-ics-prd-301>;tag=1c1339531455
   To: <sip:0170993660@10.3.1.220;user=phone>
   Call-ID: 13395229682542018214736@10.3.1.231
   CSeq: 1 INVITE
   Contact: <sip:33183817938@10.3.1.231:5060>
   Supported: em,100rel,timer,replaces,path,resource-priority,sdp-anat
   Allow: REGISTER,OPTIONS,INVITE,ACK,CANCEL,BYE,NOTIFY,PRACK,REFER,INFO,SUBSCRIBE,UPDATE
   Remote-Party-ID: <sip:33183817938@10.3.1.220>;party=calling;privacy=off;screen=yes;screen-ind=3;npi=1;ton=1
   Remote-Party-ID: <sip:0170993660@10.3.1.220>;party=called;npi=1;ton=2
   User-Agent: Audiocodes-Sip-Gateway-Mediant 3000/v.6.00A.056
   Content-Type: application/sdp
   Content-Length: 417

   v=0
   o=AudiocodesGW 1339507326 1339507042 IN IP4 10.3.1.231
   s=Phone-Call
   c=IN IP4 10.3.1.231
   t=0 0
   m=audio 23970 RTP/AVP 8 101
   a=rtpmap:8 PCMA/8000
   a=rtpmap:101 telephone-event/8000
   a=fmtp:101 0-15
   a=ptime:20
   a=sendrecv
   m=image 23972 udptl t38
   a=T38FaxVersion:0
   a=T38MaxBitRate:33600
   a=T38FaxMaxBuffer:3000
   a=T38FaxMaxDatagram:560
   a=T38FaxRateManagement:transferredTCF
   a=T38FaxUdpEC:t38UDPRedundancy

   ------------------------------------------------------------------------
send 477 bytes to udp/[10.9.30.152]:5060 at 23:47:39.444372:
   ------------------------------------------------------------------------
   SIP/2.0 100 Trying
   Via: SIP/2.0/UDP 10.9.30.152;branch=z9hG4bK51d.d7e922c4.0
   Via: SIP/2.0/UDP 10.3.1.220;branch=z9hG4bK51d.ba6f34d1.0
   Via: SIP/2.0/UDP 10.3.1.231;branch=z9hG4bKac1339541470
   Record-Route: <sip:10.9.30.152;lr=on>
   Record-Route: <sip:10.3.1.220;lr=on>
   From: <sip:33183817938@gv-ics-prd-301>;tag=1c1339531455
   To: <sip:0170993660@10.3.1.220;user=phone>
   Call-ID: 13395229682542018214736@10.3.1.231
   CSeq: 1 INVITE
   User-Agent: FreeSWITCH
   Content-Length: 0

   ------------------------------------------------------------------------
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [NOTICE] switch_channel.c:1104 New Channel sofia/internal_1/33183817938@gv-ics-prd-301 [ba17b1eb-961d-43fe-b820-cb469a8f292d]
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:584 (sofia/internal_1/33183817938@gv-ics-prd-301) Running State Change CS_NEW (Cur 1 Tot 69)
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] sofia.c:9874 sofia/internal_1/33183817938@gv-ics-prd-301 receiving invite from 10.9.30.152:5060 version: 1.6.19  64bit
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] sofia.c:7085 Channel sofia/internal_1/33183817938@gv-ics-prd-301 entering state [received][100]
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] sofia.c:7095 Remote SDP:
ba17b1eb-961d-43fe-b820-cb469a8f292d v=0^M
ba17b1eb-961d-43fe-b820-cb469a8f292d o=AudiocodesGW 1339507326 1339507042 IN IP4 10.3.1.231^M
ba17b1eb-961d-43fe-b820-cb469a8f292d s=Phone-Call^M
ba17b1eb-961d-43fe-b820-cb469a8f292d c=IN IP4 10.3.1.231^M
ba17b1eb-961d-43fe-b820-cb469a8f292d t=0 0^M
ba17b1eb-961d-43fe-b820-cb469a8f292d m=audio 23970 RTP/AVP 8 101^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=rtpmap:8 PCMA/8000^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=rtpmap:101 telephone-event/8000^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=fmtp:101 0-15^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=ptime:20^M
ba17b1eb-961d-43fe-b820-cb469a8f292d m=image 23972 udptl t38^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=T38FaxVersion:0^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=T38MaxBitRate:33600^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=T38FaxMaxBuffer:3000^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=T38FaxMaxDatagram:560^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=T38FaxRateManagement:transferredTCF^M
ba17b1eb-961d-43fe-b820-cb469a8f292d a=T38FaxUdpEC:t38UDPRedundancy^M
ba17b1eb-961d-43fe-b820-cb469a8f292d
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:4449 Audio Codec Compare [PCMA:8:8000:20:64000:1]/[PCMA:8:8000:20:64000:1]
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:4504 Audio Codec Compare [PCMA:8:8000:20:64000:1] ++++ is saved as a match
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:4449 Audio Codec Compare [PCMA:8:8000:20:64000:1]/[PCMU:0:8000:20:64000:1]
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:4365 Set telephone-event payload to 101@8000
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:3061 Set Codec sofia/internal_1/33183817938@gv-ics-prd-301 PCMA/8000 20 ms 160 samples 64000 bits 1 channels
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_codec.c:111 sofia/internal_1/33183817938@gv-ics-prd-301 Original read codec set to PCMA:8
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:4708 Set telephone-event payload to 101@8000
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:4767 sofia/internal_1/33183817938@gv-ics-prd-301 Set 2833 dtmf send payload to 101 recv payload to 101
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_media.c:4028 sofia/internal_1/33183817938@gv-ics-prd-301 T38 REFUSE on request
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [NOTICE] sofia.c:7566 Hangup sofia/internal_1/33183817938@gv-ics-prd-301 [CS_NEW] [INCOMPATIBLE_DESTINATION]
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:603 (sofia/internal_1/33183817938@gv-ics-prd-301) State NEW
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:584 (sofia/internal_1/33183817938@gv-ics-prd-301) Running State Change CS_HANGUP (Cur 1 Tot 69)
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:850 (sofia/internal_1/33183817938@gv-ics-prd-301) Callstate Change DOWN -> HANGUP
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:852 (sofia/internal_1/33183817938@gv-ics-prd-301) State HANGUP
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] mod_sofia.c:438 Channel sofia/internal_1/33183817938@gv-ics-prd-301 hanging up, cause: INCOMPATIBLE_DESTINATION
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] mod_sofia.c:577 Responding to INVITE with: 488
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:60 sofia/internal_1/33183817938@gv-ics-prd-301 Standard HANGUP, cause: INCOMPATIBLE_DESTINATION
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:852 (sofia/internal_1/33183817938@gv-ics-prd-301) State HANGUP going to sleep
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:619 (sofia/internal_1/33183817938@gv-ics-prd-301) State Change CS_HANGUP -> CS_REPORTING
ba17b1eb-961d-43fe-b820-cb469a8f292d 2018-04-25 23:47:39.434491 [DEBUG] switch_core_state_machine.c:584 (sofia/internal_1/33183817938@gv-ics-prd-301) Running State Change CS_REPORTING (Cur 1 Tot 69)
send 784 bytes to udp/[10.9.30.152]:5060 at 23:47:39.446918:
   ------------------------------------------------------------------------
   SIP/2.0 488 Not Acceptable Here
   Via: SIP/2.0/UDP 10.9.30.152;branch=z9hG4bK51d.d7e922c4.0
   Via: SIP/2.0/UDP 10.3.1.220;branch=z9hG4bK51d.ba6f34d1.0
   Via: SIP/2.0/UDP 10.3.1.231;branch=z9hG4bKac1339541470
   Max-Forwards: 68
   From: <sip:33183817938@gv-ics-prd-301>;tag=1c1339531455
   To: <sip:0170993660@10.3.1.220;user=phone>;tag=9USNQNQDByZ6a
   Call-ID: 13395229682542018214736@10.3.1.231
   CSeq: 1 INVITE
   User-Agent: FreeSWITCH
   Accept: application/sdp
   Allow: INVITE, ACK, BYE, CANCEL, OPTIONS, MESSAGE, INFO, UPDATE, REFER, NOTIFY
   Supported: timer, path, replaces
   Allow-Events: talk, hold, conference, refer
   Reason: Q.850;cause=88;text="INCOMPATIBLE_DESTINATION"
   Content-Length: 0
   Remote-Party-ID: "0170993660" <sip:0170993660@10.3.1.220>;party=calling;privacy=off;screen=no


Thanks with anticipation

D. Jeannerod