[Serusers] ACK not loose_routed

Greger V. Teigre greger at teigre.com
Wed Oct 11 11:54:43 CEST 2006


Short answer: yes.
Slightly longer: I have seen the same behavior. Without lr|lr=on the UA 
will (correctly) go over to strict routing and use contact in r-uri for 
the ACK. As long as only your record-route disappeared (i.e. you are the 
only hop in-between the UAS and UAC) this works.  As your external proxy 
is B2BUA (at least for signalling), your fine if you relay the ACK.
I'm not sure exactly when this happens and why, I seem to remember I 
posted something on this behavior for sjphone a while back, but I'm not 
capable of finding it.
g-)

Cesc wrote:
> Hello everyone!
>
> I have my system based on ser 0.9.6. Internal calls work just fine.
> I am now trying to interop with another system. It has a sort of
> asterisk functionality, but it is not asterisk, it is a private
> software company product.
>
> my.phone --------->   my.ser.proxy  ------------->   external.proxy
> ------------->  external phone
> 10.111.0.119           10.111.0.50                   10.111.0.20
>                 10.111.0.144
>
> There is no firewall or nat in the way.
>
> The problem, i think, is that the external.proxy is buggy. I told
> that to the company, but who knows when they will fix this.
>
> * Look at the OK (message #9 and #10). My.ser.proxy record-routes all
> invites. The Record-route headers reach the external.phone, which
> copies them in the OK
> message, sends the OK to the external.proxy ... and when this forwards
> it to my.ser.proxy, they are gone! The OK reaches my.phone, but then
> it generates my
> problem: the ACK. It contains NO ROUTE headers and the r-uri is also
> simply pointing to the external.proxy.
> If the ACK had the ROUTE headers, my.ser.proxy would loose_route the
> message and voila!
> But as loose_route() returns false, my (maybe bad) config file gets
> confused and treats it like a "new" call ... so it lookup("location")
> of the ACK r-ruri fails,
> and the ACK is dropped.
> Should i modify the config file so that ACK, if not loose_route'd, are
> simply t_relay'd?
>
> * They also modify the contact field. The reason is because behind the
> external.proxy could be H323 or SIP phones, so they sort of want to be
> a termination as far as signalling is concerned.
>
> I attach the message flow, hope it helps ... Thanks!
>
> Cesc
> ------------------------------------------------------------------------
>
>
> No.     Time           Source                Destination           Protocol Info
>       1 0.000000000    10.111.0.119          10.111.0.50           SIP/SDP  Request: INVITE sip:6007 at 10.111.0.20, with session description
> Session Initiation Protocol
>     Request-Line: INVITE sip:6007 at 10.111.0.20 SIP/2.0
>     Message Header
>         Via: SIP/2.0/UDP 10.111.0.119;rport;branch=z9hG4bK0a6f0077000004b2452bb819000009f00000191e
>         Content-Length: 337
>         Contact: <sip:7005 at 10.111.0.119:5060>
>         Call-ID: D95A2208-3031-44E8-862E-2877A042900D at 10.111.0.119
>         Content-Type: application/sdp
>         CSeq: 1 INVITE
>         From: "7005"<sip:7005 at 10.111.0.50:5060>;tag=12083790462495
>         Max-Forwards: 70
>         To: <sip:6007 at 10.111.0.20>
>         User-Agent: SJphone/1.60.289a (SJ Labs)
>     Message body
>         Session Description Protocol
>             Session Description Protocol Version (v): 0
>             Owner/Creator, Session Id (o): - 3369481881 3369481881 IN IP4 10.111.0.119
>             Session Name (s): SJphone
>             Connection Information (c): IN IP4 10.111.0.119
>             Time Description, active time (t): 0 0
>             Session Attribute (a): direction:active
>             Media Description, name and address (m): audio 49248 RTP/AVP 3 97 98 8 0 101
>             Media Attribute (a): rtpmap:3 GSM/8000
>             Media Attribute (a): rtpmap:97 iLBC/8000
>             Media Attribute (a): rtpmap:98 iLBC/8000
>             Media Attribute (a): fmtp:98 mode=20
>             Media Attribute (a): rtpmap:8 PCMA/8000
>             Media Attribute (a): rtpmap:0 PCMU/8000
>             Media Attribute (a): rtpmap:101 telephone-event/8000
>             Media Attribute (a): fmtp:101 0-11,16
>
> No.     Time           Source                Destination           Protocol Info
>       3 0.001209000    10.111.0.50           10.111.0.20           SIP/SDP  Request: INVITE sip:6007 at 10.111.0.20:5060, with session description
> Session Initiation Protocol
>     Request-Line: INVITE sip:6007 at 10.111.0.20:5060 SIP/2.0
>     Message Header
>         Record-Route: <sip:10.111.0.50;ftag=12083790462495;lr=on>
>         Via: SIP/2.0/UDP 10.111.0.50;branch=z9hG4bK2eff.75fbc652.0
>         Via: SIP/2.0/UDP 10.111.0.119;rport=5060;branch=z9hG4bK0a6f0077000004b2452bb819000009f00000191e
>         Content-Length: 337
>         Contact: <sip:7005 at 10.111.0.119:5060>
>         Call-ID: D95A2208-3031-44E8-862E-2877A042900D at 10.111.0.119
>         Content-Type: application/sdp
>         CSeq: 1 INVITE
>         From: "7005"<sip:7005 at 10.111.0.50:5060>;tag=12083790462495
>         Max-Forwards: 16
>         To: <sip:6007 at 10.111.0.20>
>         User-Agent: SJphone/1.60.289a (SJ Labs)
>     Message body
>         Session Description Protocol
>             Session Description Protocol Version (v): 0
>             Owner/Creator, Session Id (o): - 3369481881 3369481881 IN IP4 10.111.0.119
>             Session Name (s): SJphone
>             Connection Information (c): IN IP4 10.111.0.119
>             Time Description, active time (t): 0 0
>             Session Attribute (a): direction:active
>             Media Description, name and address (m): audio 49248 RTP/AVP 3 97 98 8 0 101
>             Media Attribute (a): rtpmap:3 GSM/8000
>             Media Attribute (a): rtpmap:97 iLBC/8000
>             Media Attribute (a): rtpmap:98 iLBC/8000
>             Media Attribute (a): fmtp:98 mode=20
>             Media Attribute (a): rtpmap:8 PCMA/8000
>             Media Attribute (a): rtpmap:0 PCMU/8000
>             Media Attribute (a): rtpmap:101 telephone-event/8000
>             Media Attribute (a): fmtp:101 0-11,16
>
> No.     Time           Source                Destination           Protocol Info
>       5 0.040629000    10.111.0.20           10.111.0.144          SIP/SDP  Request: INVITE sip:6007 at 10.111.0.144:5060;transport=UDP, with session description
> Session Initiation Protocol
>     Request-Line: INVITE sip:6007 at 10.111.0.144:5060;transport=UDP SIP/2.0
>     Message Header
>         Via: SIP/2.0/UDP 10.111.0.20:5060;branch=z9hG4bKm27749469
>         Via: SIP/2.0/UDP 10.111.0.50;branch=z9hG4bK2eff.75fbc652.0
>         Via: SIP/2.0/UDP 10.111.0.119;rport=5060;branch=z9hG4bK0a6f0077000004b2452bb819000009f00000191e
>         RECORD-ROUTE: <sip:10.111.0.50;ftag=12083790462495;lr=on>
>         From: "7005"<sip:7005 at 10.111.0.50:5060>;tag=12083790462495
>         To: <sip:6007 at 10.111.0.20>
>         Call-ID: D95A2208-3031-44E8-862E-2877A042900D at 10.111.0.119
>         CSeq: 1 INVITE
>         Max-Forwards: 16
>         Contact: <sip:10.111.0.20>
>         User-Agent: SJphone/1.60.289a (SJ Labs)
>         Content-Type: application/sdp
>         Content-Length: 337
>     Message body
>         Session Description Protocol
>             Session Description Protocol Version (v): 0
>             Owner/Creator, Session Id (o): - 3369481881 3369481881 IN IP4 10.111.0.119
>             Session Name (s): SJphone
>             Connection Information (c): IN IP4 10.111.0.119
>             Time Description, active time (t): 0 0
>             Session Attribute (a): direction:active
>             Media Description, name and address (m): audio 49248 RTP/AVP 3 97 98 8 0 101
>             Media Attribute (a): rtpmap:3 gsm/8000
>             Media Attribute (a): rtpmap:97 ilbc/8000
>             Media Attribute (a): rtpmap:98 ilbc/8000
>             Media Attribute (a): fmtp:98 mode=20
>             Media Attribute (a): rtpmap:8 pcma/8000
>             Media Attribute (a): rtpmap:0 pcmu/8000
>             Media Attribute (a): rtpmap:101 telephone-event/8000
>             Media Attribute (a): fmtp:101 0-11,16
>
> No.     Time           Source                Destination           Protocol Info
>       9 3.736665000    10.111.0.144          10.111.0.20           SIP/SDP  Status: 200 OK, with session description
> Session Initiation Protocol
>     Status-Line: SIP/2.0 200 OK
>     Message Header
>         Via: SIP/2.0/UDP 10.111.0.20:5060;branch=z9hG4bKm27749469
>         Via: SIP/2.0/UDP 10.111.0.50;branch=z9hG4bK2eff.75fbc652.0
>         Via: SIP/2.0/UDP 10.111.0.119;rport=5060;branch=z9hG4bK0a6f0077000004b2452bb819000009f00000191e
>         Record-Route: <sip:10.111.0.50;ftag=12083790462495;lr=on>
>         Call-ID: D95A2208-3031-44E8-862E-2877A042900D at 10.111.0.119
>         CSeq: 1 INVITE
>         From: "7005"<sip:7005 at 10.111.0.50:5060>;tag=12083790462495
>         To: <sip:6007 at 10.111.0.20>;tag=0rxFXxkiza46soF7
>         Contact: <sip:6007 at 10.111.0.144:5060>
>         Allow: INVITE, ACK, OPTIONS, BYE, CANCEL, REGISTER, REFER, NOTIFY, INFO, PRACK, UPDATE
>         Supported: 100rel, replaces
>         Content-Type: application/sdp
>         Content-Length: 140
>     Message body
>         Session Description Protocol
>             Session Description Protocol Version (v): 0
>             Owner/Creator, Session Id (o): 6007 14194531 23224216 IN IP4 10.111.0.144
>             Session Name (s): SIP CALL
>             Connection Information (c): IN IP4 10.111.0.144
>             Time Description, active time (t): 0 0
>             Media Description, name and address (m): audio 10000 RTP/AVP 8
>             Media Attribute (a): rtpmap:8 PCMA/8000
>
> No.     Time           Source                Destination           Protocol Info
>      10 3.751306000    10.111.0.20           10.111.0.50           SIP/SDP  Status: 200 OK, with session description
> Session Initiation Protocol
>     Status-Line: SIP/2.0 200 OK
>     Message Header
>         Via: SIP/2.0/UDP 10.111.0.50;branch=z9hG4bK2eff.75fbc652.0
>         Via: SIP/2.0/UDP 10.111.0.119;rport=5060;branch=z9hG4bK0a6f0077000004b2452bb819000009f00000191e
>         From: "7005"<sip:7005 at 10.111.0.50:5060>;tag=12083790462495
>         To: <sip:6007 at 10.111.0.20>;tag=0rxFXxkiza46soF7
>         Call-ID: D95A2208-3031-44E8-862E-2877A042900D at 10.111.0.119
>         CSeq: 1 INVITE
>         Contact: <sip:10.111.0.20:5060>
>         Content-Type: application/sdp
>         Content-Length: 140
>     Message body
>         Session Description Protocol
>             Session Description Protocol Version (v): 0
>             Owner/Creator, Session Id (o): 6007 14194531 23224216 IN IP4 10.111.0.144
>             Session Name (s): SIP CALL
>             Connection Information (c): IN IP4 10.111.0.144
>             Time Description, active time (t): 0 0
>             Media Description, name and address (m): audio 10000 RTP/AVP 8
>             Media Attribute (a): rtpmap:8 pcma/8000
>
> No.     Time           Source                Destination           Protocol Info
>      11 3.751589000    10.111.0.50           10.111.0.119          SIP/SDP  Status: 200 OK, with session description
> Session Initiation Protocol
>     Status-Line: SIP/2.0 200 OK
>     Message Header
>         Via: SIP/2.0/UDP 10.111.0.119;rport=5060;branch=z9hG4bK0a6f0077000004b2452bb819000009f00000191e
>         From: "7005"<sip:7005 at 10.111.0.50:5060>;tag=12083790462495
>         To: <sip:6007 at 10.111.0.20>;tag=0rxFXxkiza46soF7
>         Call-ID: D95A2208-3031-44E8-862E-2877A042900D at 10.111.0.119
>         CSeq: 1 INVITE
>         Contact: <sip:10.111.0.20:5060>
>         Content-Type: application/sdp
>         Content-Length: 140
>     Message body
>         Session Description Protocol
>             Session Description Protocol Version (v): 0
>             Owner/Creator, Session Id (o): 6007 14194531 23224216 IN IP4 10.111.0.144
>             Session Name (s): SIP CALL
>             Connection Information (c): IN IP4 10.111.0.144
>             Time Description, active time (t): 0 0
>             Media Description, name and address (m): audio 10000 RTP/AVP 8
>             Media Attribute (a): rtpmap:8 pcma/8000
>
> No.     Time           Source                Destination           Protocol Info
>      12 3.756127000    10.111.0.119          10.111.0.50           SIP      Request: ACK sip:10.111.0.20:5060
> Session Initiation Protocol
>     Request-Line: ACK sip:10.111.0.20:5060 SIP/2.0
>     Message Header
>         Via: SIP/2.0/UDP 10.111.0.119;rport;branch=z9hG4bK0a6f0077000004b2452bb81d00000c5f00001922
>         Content-Length: 0
>         Call-ID: D95A2208-3031-44E8-862E-2877A042900D at 10.111.0.119
>         CSeq: 1 ACK
>         From: "7005"<sip:7005 at 10.111.0.50:5060>;tag=12083790462495
>         Max-Forwards: 70
>         To: <sip:6007 at 10.111.0.20>;tag=0rxFXxkiza46soF7
>         User-Agent: SJphone/1.60.289a (SJ Labs)
>   
> ------------------------------------------------------------------------
>
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