Hello,
Sorry if this is a tired, worn question, but I've not dealt much with Kamailio's SRV support before:
If a registrant has a contact binding whose domain component is subject to an SRV lookup with load-balanced or weighted entries, how does one solve the problem of ensuring that subsequent in-dialog requests go to the same host as the initial INVITE? Does Kamailio offer some facility for doing this? Is it somehow accommodated by SIP?
-- Alex
On 05/25/2016 04:32 PM, Alex Balashov wrote:
Hello,
Sorry if this is a tired, worn question, but I've not dealt much with Kamailio's SRV support before:
If a registrant has a contact binding whose domain component is subject to an SRV lookup with load-balanced or weighted entries, how does one solve the problem of ensuring that subsequent in-dialog requests go to the same host as the initial INVITE? Does Kamailio offer some facility for doing this? Is it somehow accommodated by SIP?
-- Alex
Clarification:
Why would this be wanted?
I ask, as if you were using a srv record as the result of a load balance lookup, wouldn't the point be to be able to quickly change location of the domain in case of an outage/issue?
Otherwise, I'm not positive the benefit of doing a srv lookup for this scenario.
Oh, if only I were personally responsible for the initiative behind this question... :)
My best guess is that SRV is viewed here as an LB mechanism only and without any interest in fail over.
-- Alex
-- Principal, Evariste Systems LLC (www.evaristesys.com)
Sent from my Google Nexus.
You can use a htable for the rescue, either storing the selected IP within onsend_route or when the replies are coming back. An alternative is to store as a dialog variable.
Cheers, Daniel
On 25/05/16 22:53, Alex Balashov wrote:
Oh, if only I were personally responsible for the initiative behind this question... :)
My best guess is that SRV is viewed here as an LB mechanism only and without any interest in fail over.
-- Alex
-- Principal, Evariste Systems LLC (www.evaristesys.com)
Sent from my Google Nexus.
SIP Express Router (SER) and Kamailio (OpenSER) - sr-users mailing list sr-users@lists.sip-router.org http://lists.sip-router.org/cgi-bin/mailman/listinfo/sr-users
On 05/26/2016 11:11 AM, Daniel-Constantin Mierla wrote:
You can use a htable for the rescue, either storing the selected IP within onsend_route or when the replies are coming back. An alternative is to store as a dialog variable.
Okay, so I'd need to keep my own state. If I understood correctly, SIP provides no more fundamental facility for addressing this. Right?
On 26/05/16 17:40, Alex Balashov wrote:
On 05/26/2016 11:11 AM, Daniel-Constantin Mierla wrote:
You can use a htable for the rescue, either storing the selected IP within onsend_route or when the replies are coming back. An alternative is to store as a dialog variable.
Okay, so I'd need to keep my own state. If I understood correctly, SIP provides no more fundamental facility for addressing this. Right?
I haven't checked right now the 3263 (iirc), but as far as I remember, there is no nothing enforced in this regard. If a UA wants to use a fixed point, then after the initial routing upon DNS lookup after location service handling, then the device should set the Contact in 200ok with an IP address if it doesn't want a DNS lookup to be done based on hostname of its Contact address.
Cheers, Daniel
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Alex Balashov -
Daniel-Constantin Mierla -
Fred Posner