[Serusers] record_route() & record_route_preset() di

Kostas Marneris K.Marneris at otenet.gr
Tue Aug 14 13:00:22 CEST 2007


Hello,

I have a question regarding record_route() & record_route_preset() functions.
I faced up a problem with some SIP clients with inbound calls where I believe
that it's related with these functions.

1/ When I use the "record_route()" function in a single server SER setup
I have the following "Record-Route:" header in INVITE mesg from SER to called SIP UA:

Record-Route: <sip:1.2.3.4;ftag=AAA-19972;lr=on>
...

2/ When I use the "record_route_preset()" function in a double server SER setup
(2 SER servers behind a Cisco CSM Load balancer),
example : record_route_preset("5.6.7.8");
I have the following "Record-Route:" header in INVITE mesg (SER -> called SIP UA):

Record-Route: <sip:1234567890 at 5.6.7.8;ftag=XPH-5307;lr=on>
...


In first case the SIP UA accepts the inbound call and everything is Ok.
In second case the same SIP UA doesn't replied with '100 Trying' mesg back to SER.

In the second case, SER also adds the called number "1234567890" in the Record-Route header.
Why there is this difference and if that can cause problems (incompatibility) to some
SIP clients ?


thanks for any hint,
Kostas



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