[sr-dev] double record-routing also at outbound edge

[Juha Heinanen]

Peter Dunkley writes:

> If the edge proxy does not add a flow-token to the Path: header how will 
> INVITEs ever get to client devices behind NATs?

they do, because when ua behind NAT registers, edge proxy adds received
param to path header that contains the ip address/port of the ua at the
nat box.

i just tested and it worked fine.

register from edge proxy to registrar (note received in path header):

Session Initiation Protocol
    Request-Line: REGISTER sip:test.fi SIP/2.0
    Message Header
        Via: SIP/2.0/TCP 192.98.102.10:5070;branch=z9hG4bKf1e.275e3219c0b2e50b00e32ce46abf509c.0
        Via: SIP/2.0/WS lkh33af7k3up.invalid;rport=62121;received=192.98.104.2;branch=z9hG4bK2333142
        Max-Forwards: 16
        To: <sip:jh at test.fi>
        From: "Juha Heinanen" <sip:jh at test.fi>;tag=hesufr3300
        Call-ID: fv0rqlp5tcdv2uden3grb6
        CSeq: 88 REGISTER
        Contact: <sip:rebu3li2 at lkh33af7k3up.invalid;transport=ws>;reg-id=1;+sip.instance="<urn:uuid:480356d7-8507-4ad8-bf27-292d463224f2>";expires=600
        Allow: ACK,CANCEL,BYE,OPTIONS,INVITE,MESSAGE
        Supported: path, outbound, gruu
        User-Agent: JsSIP 0.3.0
        Content-Length: 0
        Path: <sip:192.98.102.10:5070;transport=tcp;lr;received=sip:192.98.104.2:62121%3Btransport%3Dws>

invite from registrar/home proxy to edge proxy (note route header
containing received):

Session Initiation Protocol
    Request-Line: INVITE sip:rebu3li2 at lkh33af7k3up.invalid;transport=ws SIP/2.0
    Message Header
        Record-Route: <sip:192.98.102.20:5070;transport=tcp;r2=on;lr>
        Record-Route: <sip:192.98.102.20;transport=tcp;r2=on;lr>
        Via: SIP/2.0/TCP 192.98.102.20:5070;branch=z9hG4bKd777.2d854da9ddf108b1a4f6278cdd384c2b.0;i=2
        Via: SIP/2.0/TCP 192.98.102.10:5064;branch=z9hG4bKbd2c5fb6ce49eaec;rport=51603
        Contact: <sip:0x262d610 at 192.98.102.10:5064;alias=192.98.102.10~51603~2;transport=tcp>
        Max-Forwards: 16
        Route: <sip:192.98.102.10:5070;transport=tcp;lr;received=sip:192.98.104.2:62121%3Btransport%3Dws>
        To: <sip:jh at test.fi>
        From: "" <sip:test at test.fi>;tag=c8c7348f9ae4a7d4
        Call-ID: 4095ecb4e893586f
        CSeq: 33849 INVITE
        User-Agent: baresip v0.4.3 (x86_64/linux)
        Allow: INVITE,ACK,BYE,CANCEL,REFER,NOTIFY,SUBSCRIBE,INFO
        Content-Type: application/sdp
        Content-Length: 521
        P-Asserted-Identity: <sip:+35852345671 at test.fi>
    Message Body

-- juha