[SR-Users] Loose Routing with Cisco router

Alex Balashov abalashov at evaristesys.com
Wed Aug 14 11:06:19 CEST 2013


I use Kamailio extensively with Cisco AS5xxx series gateways and they have never had a problem dealing with Kamailio's RRs and lr values. 


Daniel-Constantin Mierla <miconda at gmail.com> wrote:
>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.
>>
>>
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>list
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--
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Alex Balashov - Principal
Evariste Systems LLC
235 E Ponce de Leon Ave
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Decatur, GA 30030
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Tel: +1-678-954-0670
Web: http://www.evaristesys.com/, http://www.alexbalashov.com



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