[SR-Users] MetaSwitch ignores Contact: header

[Daniel-Constantin Mierla]

Hello,

indeed, Metaswitch breaks SIP routing and the best is fixing their side,
as pointed by Alex.

However, Kamailio is flexible enough to solve this issue, eventually
temporarily until the peer is fixing its side.

Do you get Route header in the ACK? That would be crucial in selecting
the ACK for 200ok vs negative responses.

Then, solution can be based on htable or parameters in Route or Contact
headers, where to store the IP/port of the afferent Asterisk and use it
for routing.

Cheers,
Daniel

On 08/07/15 02:47, Markus wrote:
> Dear list,
>
> I'm running kamailio-4.2.3-3.1.x86_64 in a very simple setup: one
> Asterisk server behind kamailio. But I'm using dispatcher, the other
> servers are just down currently. :)
>
> Different vendors route DIDs to kamailio's IP and kamailio handles the
> communication towards Asterisk.
>
> Now I have a new vendor who uses MetaSwitch, and there is a problem.
> All calls get dropped with a BYE from the Asterisk side after 32
> seconds because Asterisk never receives the ACK, because kamailio
> doesn't forward it, because MetaSwitch sends it as
>
> ACK sip:number at KAMAILIO-IP
>
> instead of
>
> ACK sip:number at ASTERISK-IP
>
> That means MetaSwitch ignores what we tell it in the Contact: header.
>
> Is this MetaSwitch'es "fault" or kamailio's? All other vendors work
> fine without problems. Therefore I have compared an "old" vendor and
> the new one. Here is the result that shows the difference:
>
> Old vendor - works:
>
> OLDVENDOR-IP.5060 > KAMAILIO-IP.5060: INVITE sip:number at KAMAILIO-IP
> KAMAILIO-IP.5060 > OLDVENDOR-IP.5060: SIP/2.0 100 trying
>
>  KAMAILIO-IP.5060 > ASTERISK-IP.5060: INVITE sip:number at KAMAILIO-IP
>  ASTERISK-IP.5060 > KAMAILIO-IP.5060: SIP/2.0 100 Trying
>
>  ASTERISK-IP.5060 > KAMAILIO-IP.5060: SIP/2.0 200 OK
> KAMAILIO-IP.5060 > OLDVENDOR-IP.5060: SIP/2.0 200 OK
>
> OLDVENDOR-IP.5060 > KAMAILIO-IP.5060: ACK sip:number at ASTERISK-IP:5060
>  KAMAILIO-IP.5060 > ASTERISK-IP.5060: ACK sip:number at ASTERISK-IP:5060
>
>
> New vendor with MetaSwitch - doesn't work:
>
> NEWVENDOR-IP.5060 > KAMAILIO-IP.5060: INVITE sip:number at KAMAILIO-IP:5060
> KAMAILIO-IP.5060 > NEWVENDOR-IP.5060: SIP/2.0 100 trying
>
>  KAMAILIO-IP.5060 > ASTERISK-IP.5060: INVITE sip:number at KAMAILIO-IP:5060
>  ASTERISK-IP.5060 > KAMAILIO-IP.5060: SIP/2.0 100 Trying
>
>  ASTERISK-IP.5060 > KAMAILIO-IP.5060: SIP/2.0 200 OK
> KAMAILIO-IP.5060 > NEWVENDOR-IP.5060: SIP/2.0 200 OK
>
> NEWVENDOR-IP.5060 > KAMAILIO-IP.5060: ACK sip:number at KAMAILIO-IP:5060
>  ASTERISK-IP.5060 > KAMAILIO-IP.5060: SIP/2.0 200 OK
> KAMAILIO-IP.5060 > NEWVENDOR-IP.5060: SIP/2.0 200 OK
>
> NEWVENDOR-IP.5060 > KAMAILIO-IP.5060: ACK sip:number at KAMAILIO-IP:5060
>  ASTERISK-IP.5060 > KAMAILIO-IP.5060: SIP/2.0 200 OK
> KAMAILIO-IP.5060 > NEWVENDOR-IP.5060: SIP/2.0 200 OK
>
> NEWVENDOR-IP.5060 > KAMAILIO-IP.5060: ACK sip:number at KAMAILIO-IP:5060
> ... and so on ...
>
> Can I do something about this or is a change on MetaSwitch'es side in
> order?
>
> Thank you!
> Markus
>
>
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-- 
Daniel-Constantin Mierla
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