[SR-Users] Loose Routing with Cisco router

[Daniel-Constantin Mierla]

Hello,

what model the cisco router is?

 From what I understand, you want to go from:

[a] ===> [kamailio] ===> [b]

to:

[a] ===> [kamailio] ===> [cisco] ===> [b]

The usual will be that kamailio sets the r-uri to [b] and dsturi 
(outbound proxy) to [cisco] and then relay. The cisco should have some 
config options just to forward the traffic based on r-uri, however I 
never had to deal cisco configs. Maybe you add a Route header with 
[cisco];lr, then it should match itself in the route header and send to 
r-uri.

On the other hand, when I had to interoperate with cisco gateways/b2bua, 
they had no problem understanding loose routing added by kamailio.

Cheers,
Daniel

On 8/13/13 10:05 AM, David Wilson wrote:
> Hello All,
>
> I'm running Kamailio 4.0.2 on Ubuntu 12.04 (precise).
>
> I have SIP messaging flowing nicely, with UACs registering via Kamailio (as a proxy) to a Registrar.
>
> Now having problems trying to route messages via a Cisco router (12.4(25g)) using loose routing.  The plan is to allow the router to see the SIP messaging but forward it to the original location.
>
> RFC 3261 seems to cover this case in Section 16.6 part 6: "A proxy MAY have a local policy that mandates that a request visit a specific set of proxies before being delivered to the destination."
>
> Cisco documentation (SIP Configuration Guide, Cisco IOS Release 12.4) states that it implements RFC 3261, including Loose-routing.   However, from my observation the router doesn't like a request-URI with anything other than its own IP address (it returns 400 Bad Request - 'Invalid IP address'), but with any attempt to 'decorate' the URI with lr and/or maddr= parameters it returns 400 Bad Request - 'Malformed/Missing' URL.  One of these messages is returned regardless of anything I've tried with Via, Record-Route or Route headers.
>
> Desired behaviour is for the router to remain in the route-set.  A different configuration has shown me that this will achieve the required outcome, the tricky part now is just getting that first request to route.  I know several ways to make Kamailio send to the router, but the router is not behaving as I expect when I preload a route set (with Route: headers).
>
> Recognising that this is probably more of a Cisco problem than Kamailio, can anyone confirm whether a Cisco router implements loose-routing when receiving messages, or only when sending?
>
> Regards,
> Dave.
>
>
> _______________________________________________
> SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list
> sr-users at lists.sip-router.org
> http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users

-- 
Daniel-Constantin Mierla - http://www.asipto.com
http://twitter.com/#!/miconda - http://www.linkedin.com/in/miconda