[Serusers] UAs not respecting Record Route

Samy Touati samy at tunix.com
Sun Feb 15 20:46:38 CET 2004

I do have the following situation:
UA1 calls UA2 going through ser 0.8.12. All signaling is Recourd Routed and
go through ser.
UA2 doesn't answer and I do have a t_on_failure to go to UA3.
UA3 receives INVITES from ser, and answer with a 200/OK with sdp, this
messages goes through ser which forward it to UA1.
UA1 sends an ACK to ser having this in message:
Session Initiation Protocol
    Request line: ACK sip:ua3 at SIP/2.0
        Method: ACK
    Message Header
        Via: SIP/2.0/UDP;branch=z9hG4bk-7f415771
        From: test1 <sip:ua1 at vocal.ipsound.net>;tag=eb646133bf338b12
        To: <sip:ua2 at vocal.ipsound.net>;tag=as47221fa0
        Call-ID: a66804e6-5ac924fd at
        CSeq: 102 ACK
        Max-Forwards: 70
        Route: <sip:sip-proxy at ser-domain.com;ftag=eb646133bf338b12;lr=on>
        Proxy-Authorization: Digest username="        
        Contact: ua1 <sip:ua1 at>
        User-Agent: Sipura/SPA2000-1.0.10
        Content-Length: 0
Ser is supposed to follow the route, and ends up looking into the location
table and re-forwards the request to UA2 again (even if it already timed out
Now I do have another UA which in this same scenario sends the correct ACK:
Session Initiation Protocol
    Request line: ACK sip:sip-proxy at ser-domain.com SIP/2.0
        Method: ACK
    Message Header
        Route: <sip:ua3 at>
        Via: SIP/2.0/UDP
        From: ua1 <sip:ua1 at ser-domain.com;user=phone>;tag=3551608275
        To: <sip:ua2 at ser-domain.com;user=phone>;tag=as112d04ea
        Call-ID: 2653016335 at
        CSeq: 2 ACK
        User-Agent: Cisco ATA 186  v3.0.0 atasip (031210A)
        Proxy-Authorization: Digest username
        Content-Length: 0
In this case ser follow the route header, and ends up sending the ACK to
Snom phone with 2.03o firmware as well as sipura with 1.0.10 and 1.0.29b
firmware have the same wrong behaviour.
What is the right way of having this ?
My understanding is that in record route situation, ser looks into the route
header, and sends the message based on it. Here I do have User Agents which
seem to create an ACK message ignoring it should go to a sip proxy .
Am I missing something here ?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.sip-router.org/pipermail/sr-users/attachments/20040215/3fc38e47/attachment.htm>

More information about the sr-users mailing list