In the following, I have a T.38 Fax call in which I'm forcing RTPProxy. The signalling follows this draft (http://tools.ietf.org/html/draft-mule-sip-t38callflows-02#section-5.2), but the UDPTL media seems to have problems. The problem is that OpenSER/RTPProxy seems to ignore the address in the SDP of the "200 OK". As I understand it, RTPProxy should, adequately enough, proxy the UDPTL. (not just rtp) The call flow is as follows: UC -> EDGE EDGE -> OpenSER OpenSER -> EU (not shown in this trace)
NOTE: IPs have been changed to protect the innocent ;-) 192.168.174.156 represents our UC's (Underlying Carrier's) IP 192.168.48.88 represents our edge proxy 192.168.202.10 represents our OpenSER box
Below, I have what I consider to be the "relevent" packets with large portions of repetition SNIP'd.... Below that, I have the two (again, what I consider to be) relevent packets with details of the SDP
In both of the SDP details, our edge uses the UC's IP (192.168.174.156) in the c= line of the SDP. I don't see that being overwritten in any of the "media-specific" sections following. OpenSER/RTPProxy handle the RTP appropriately (to the best of my knowledge) but send the t.38 UDPTL media back to our edge which is, of course, rejecting it.
"No.", "Time", "Source", "Destination", "Protocol", "Info" "1", "0.000000", "192.168.48.88", "192.168.202.10", "SIP/SDP", "Request: INVITE sip:1NPANXX0119@192.168.202.10:6080, with session description" "2", "0.005027", "192.168.202.10", "192.168.48.88", "SIP", "Status: 100 Trying" "3", "0.286018", "192.168.202.10", "192.168.48.88", "SIP", "Status: 180 Ringing" "4", "9.397591", "192.168.202.10", "192.168.48.88", "SIP/SDP", "Status: 200 OK, with session description" "5", "9.410633", "192.168.202.10", "192.168.48.88", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3122798450, Seq=5169, Time=374804094" "6", "9.439195", "192.168.48.88", "192.168.202.10", "SIP", "Request: ACK sip:1NPANXX0119@192.168.202.10:6080" "7", "9.440987", "192.168.202.10", "192.168.48.88", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3122798450, Seq=5170, Time=374804334" "8", "9.448560", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "9", "9.470710", "192.168.202.10", "192.168.48.88", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3122798450, Seq=5171, Time=374804574" "10","9.479789","69.25.48.88","67.15.202.10","ICMP","Destination unreachable (Port unreachable)" "11","9.490158","207.218.174.156","67.15.202.10","RTP","PT=ITU-T G.711 PCMU, SSRC=0xCF806328, Seq=0, Time=0, Mark " "12","9.500186","67.15.202.10","207.218.174.156","RTP","PT=ITU-T G.711 PCMU, SSRC=0xBA221F72, Seq=5172, Time=374804814 " "13","9.509146","69.25.48.88","67.15.202.10","ICMP","Destination unreachable (Port unreachable)" "14","9.510270","207.218.174.156","67.15.202.10","RTP","PT=ITU-T G.711 PCMU, SSRC=0xCF806328, Seq=1, Time=160 " "15","9.530265","207.218.174.156","67.15.202.10","RTP","PT=ITU-T G.711 PCMU, SSRC=0xCF806328, Seq=2, Time=320 " "16","9.530283","67.15.202.10","207.218.174.156","RTP","PT=ITU-T G.711 PCMU, SSRC=0xBA221F72, Seq=5173, Time=374805054 " ~~~~ SNIP ~~~~ "174", "11.430039", "192.168.174.156", "192.168.202.10", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3481297704, Seq=97, Time=15520" "175", "11.450027", "192.168.174.156", "192.168.202.10", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3481297704, Seq=98, Time=15680" "176", "11.457118", "192.168.202.10", "192.168.48.88", "SIP/SDP", "Request: INVITE sip:Restricted@192.168.48.88, with session description" "177", "11.468025", "192.168.202.10", "192.168.174.156", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "178", "11.470013", "192.168.174.156", "192.168.202.10", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3481297704, Seq=99, Time=15840" "179", "11.490125", "192.168.174.156", "192.168.202.10", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3481297704, Seq=100, Time=16000" "180", "11.492010", "192.168.202.10", "192.168.174.156", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "181", "11.499118", "192.168.48.88", "192.168.202.10", "SIP", "Status: 100 Trying" "182", "11.510111", "192.168.174.156", "192.168.202.10", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3481297704, Seq=101, Time=16160" "183", "11.515999", "192.168.202.10", "192.168.174.156", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "184", "11.530100", "192.168.174.156", "192.168.202.10", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3481297704, Seq=102, Time=16320" "185", "11.540998", "192.168.202.10", "192.168.174.156", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "186", "11.550087", "192.168.174.156", "192.168.202.10", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3481297704, Seq=103, Time=16480" "187", "11.570073", "192.168.174.156", "192.168.202.10", "RTP", "Payload type=ITU-T G.711 PCMU, SSRC=3481297704, Seq=104, Time=16640" "188", "11.580068", "192.168.174.156", "192.168.202.10", "RTP", "Unknown RTP version 0" "189", "11.581986", "192.168.202.10", "192.168.174.156", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "190", "11.590061", "192.168.174.156", "192.168.202.10", "RTP", "Unknown RTP version 0" "191", "11.599929", "192.168.174.156", "192.168.202.10", "RTP", "Unknown RTP version 0" "192", "11.605977", "192.168.202.10", "192.168.174.156", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "193", "11.608549", "192.168.48.88", "192.168.202.10", "SIP/SDP", "Status: 200 OK, with session description" "194", "11.630936", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "195", "11.660168", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "196", "11.668760", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "197", "11.690405", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "198", "11.697992", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "199", "11.720762", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "200", "11.728847", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "201", "11.750120", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=32768 [UNKNOWN PER: unknown choice extension][Malformed Packet]" "202", "11.758827", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "203", "11.780601", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=32768 t30ind: no-signal hdlc-fcs-BAD-sig-end t4-non-ecm-sig-end [Malformed?] hdlc-fcs-BAD-sig-end hdlc-data[Malformed Packet]" "204", "11.788059", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "205", "11.811073", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=32768 t30ind: no-signal hdlc-fcs-BAD-sig-end t4-non-ecm-sig-end [Malformed?] hdlc-fcs-BAD-sig-end hdlc-sig-end[Malformed Packet]" "206", "11.818665", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "207", "11.833039", "192.168.202.10", "192.168.48.88", "SIP", "Request: ACK sip:Restricted@192.168.48.88:5060" "208", "11.839935", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=32768 t30ind: cng hdlc-fcs-BAD-sig-end t4-non-ecm-sig-end [Malformed?] hdlc-fcs-BAD-sig-end hdlc-fcs-OK[Malformed Packet]" "209", "11.849145", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "210", "11.868409", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=00000 t30ind: no-signal" "211", "11.878000", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "212", "11.905983", "192.168.48.88", "192.168.202.10", "ICMP", "Destination unreachable (Port unreachable)" "213", "14.428661", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=00001 t30ind: v21-preamble" ~~~~ SNIP ~~~~ "389", "32.869453", "192.168.202.10", "192.168.48.88", "T.38", "UDP: UDPTLPacket Seq=00114 t30ind: no-signal" "390", "41.696978", "192.168.202.10", "192.168.48.88", "SIP", "Request: BYE sip:Restricted@192.168.48.88:5060" "391", "41.738094", "192.168.48.88", "192.168.202.10", "SIP", "Status: 200 OK"
No. Time Source Destination Protocol Info 1 0.000000 192.168.48.88 192.168.202.10 SIP/SDP Request: INVITE sip:1NPANXX0119@192.168.202.10:6080, with session description
Frame 1 (966 bytes on wire, 966 bytes captured) Ethernet II, Src: 00:1e:13:ca:4a:3f (00:1e:13:ca:4a:3f), Dst: Dell_ed:4a:1c (00:12:3f:ed:4a:1c) Internet Protocol, Src: 192.168.48.88 (192.168.48.88), Dst: 192.168.202.10 (192.168.202.10) User Datagram Protocol, Src Port: 5060 (5060), Dst Port: 6080 (6080) Session Initiation Protocol Request-Line: INVITE sip:1NPANXX0119@192.168.202.10:6080 SIP/2.0 Message Header Message body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): BRSDP 187392 187392 IN IP4 192.168.174.156 Session Name (s): BRSDP Session Connection Information (c): IN IP4 192.168.174.156 Time Description, active time (t): 0 0 Media Description, name and address (m): audio 53278 RTP/AVP 0 8 18 100 Media Attribute (a): rtpmap:0 PCMU/8000 Media Attribute (a): rtpmap:8 PCMA/8000 Media Attribute (a): rtpmap:18 G729/8000 Media Attribute (a): rtpmap:100 telephone-event/8000 Media Attribute (a): fmtp:100 0-15
No. Time Source Destination Protocol Info 193 11.608549 192.168.48.88 192.168.202.10 SIP/SDP Status: 200 OK, with session description
Frame 193 (1013 bytes on wire, 1013 bytes captured) Ethernet II, Src: 00:1e:13:ca:4a:3f (00:1e:13:ca:4a:3f), Dst: Dell_ed:4a:1c (00:12:3f:ed:4a:1c) Internet Protocol, Src: 192.168.48.88 (192.168.48.88), Dst: 192.168.202.10 (192.168.202.10) User Datagram Protocol, Src Port: 5060 (5060), Dst Port: 6080 (6080) Session Initiation Protocol Status-Line: SIP/2.0 200 OK Message Header Message body Session Description Protocol Session Description Protocol Version (v): 0 Owner/Creator, Session Id (o): BRSDP 187392 187393 IN IP4 192.168.174.156 Session Name (s): BRSDP Session Connection Information (c): IN IP4 192.168.174.156 Time Description, active time (t): 0 0 Media Description, name and address (m): image 53278 udptl t38 Media Attribute (a): T38FaxVersion:0 Media Attribute (a): T38MaxBitRate:14400 Media Attribute (a): T38FaxRateManagement:transferredTCF Media Attribute (a): T38FaxMaxBuffer:262 Media Attribute (a): T38FaxMaxDatagram:176 Media Attribute (a): T38FaxUdpEC:t38UDPRedundancy
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Raymond Chandler