[OpenSIPS-Users] Registrant & LB with SRV

[Antonios Psaras]

Thank you Walter for your reply.

 

Unfortunately there is no way to change Carrier's configuration so we need
to find a way to tackle the issue on our side.

 

Thanks again.

 

Regards

 

From: Walter Schober <walter.schober at neotel.at> 
Sent: Δευτέρα, 23 Ιουνίου 2025 10:37
To: OpenSIPS users mailling list <users at lists.opensips.org>
Cc: apsaras at microbase.gr
Subject: AW: [OpenSIPS-Users] Registrant & LB with SRV

 

Hello Antonis!

 

IMHO the carrier cannot expect Register and Invite going to the same
destination if the SRV for _the_ service is load-balanced.

 

We do offer such a service as carrier also but encountered the issue with LB
on nearly every device, incl. phones. Since we also need the call to be
established across the same service endpoint selected in the Register
process we set priorities on each SRV for each datacenter.

For such cases we do additionally name two A records where the endpoint must
register on both and then can do LB calls to each. Otherwise the carriers
service must allow registers and invites going different ways. It is **one**
service based on the SRV entry!

 

Br

Walter

 

Von: Users <users-bounces at lists.opensips.org
<mailto:users-bounces at lists.opensips.org> > Im Auftrag von Antonios Psaras
Gesendet: Freitag, 20. Juni 2025 11:24
An: 'OpenSIPS users mailling list' <users at lists.opensips.org
<mailto:users at lists.opensips.org> >
Betreff: [OpenSIPS-Users] Registrant & LB with SRV

 

Hello Team

 

I have the following situation.

 

A telecom carrier requires SIP Registration prior to Dial out using SIP
Domain and SRV Lookup.

 

To achieve that I am using registrant module and load balancing module.

 

The problem I have, is that in some cases registrant registers on different
SBC of the Carrier than the one resolved by Load Balancer Module so my
outbound calls are failing with 407.

 

I have two thoughts but I do not know how to implement any of those.

 

1.	Instead of using LB Modules, I will some how get the registrar IP
from registrant module and statically route the calls through that. Is there
a way to get that information from registrant module?
2.	DNS lookup is done automatically only in case of 503 or timeout. Is
there a way to force DNS lookup with in OpenSIP Script? If yes I can handle
407, force DNS Lookup, create a new branch and re-send the call.

 

Any other thoughts are welcome

 

Best regards

 

Antonis Psaras

 

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