Good point. Mobicents is on my list of projects to which I'm due to contribute something. I'll get on it shortly.
On 29 December 2014 at 11:26, Carsten Bock carsten@ng-voice.com wrote:
Hi Ben,
that's absolutely for sure! It took us ~2 years to get the DNS-SRV implementation of major DSL-Modem-Manufacturer right ;-) Nevertheless, it's the way to go for redundancy. And since Mobicents is open-source, we can probably simply provide a patch to fix it :-)
Kind regards, Carsten
2014-12-29 12:13 GMT+01:00 Ben Langfeld ben@langfeld.co.uk:
On 27 December 2014 at 23:44, Carsten Bock carsten@ng-voice.com wrote:
Hi Mahmoud,
Thy typical way, to build a Active/Active setup is by using DNS-SRV records. The two servers get different IPs and you announce both IPs using DNS to the devices. Most common User-Agents support this nowadays, so that's kind of easy. It is specified in RFC3263: "Locating SIP-Servers" (http://tools.ietf.org/html/rfc3263).
However, when using DNS-SRV records, dialogs and transactions are still associated with a single server, even though the User-Agent has an Alternative, in case one server fails. If you want to increase the HA for this, you can advertise the Domain name instead of an IP (causes more DNS-Lookups).
Just a word of caution here, there are several SIP stacks which don't
handle
SRV lookups correctly. I don't mean to discourage you from this, but
just to
be aware of it. For example, Mobicents only understands SRV record sets which return domain names. If you return IPs, Mobicents will go ahead and look them up as A records and fail.
You can share the dialog state etween two nodes by using the dialog module in db-only mode (db_mode = 1, see http://kamailio.org/docs/modules/devel/modules/dialog.html#idp15368320
).
You cannot share transactions between two nodes, only dialogs.
In addition, you can work with virtual IPs with Heartbeat/Pacemaker.
At a big operator, we've used a combination of the two: Active/Passive for one site and DNS-SRV to distribute it among different sites.
Kind regards, Carsten
2014-12-26 19:07 GMT+01:00 Mahmoud Ramadan Ali cisco.and.more.blog@gmail.com:
Hi Dears, I have successfully configured Kamailio HA using Heartbeat and
Pacemaker
so if one of the two servers should go down the other server will own the virtual IP address and take over. But i have two questions:
1.This model is considered to be Active / Passive redundancy so one server will process the SIP signaling until it goes down and i'm wondering is there is any way two achieve Active / Active redundancy and if so how the signaling will be handled on the servers so they can be aware of the transactions and dialogs traversing the servers ? does the signalling will be replicated or synchronized between the servers or what ?!
2.What about the servers DB and how they should be designed in a
cluster
mode ? i want to replicate all the DBs of the server to get consistent user registration using the subscriber table for example.
Thanks in advance and Best regards.
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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
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
-- Carsten Bock CEO (Geschäftsführer)
ng-voice GmbH Schomburgstr. 80 D-22767 Hamburg / Germany
http://www.ng-voice.com mailto:carsten@ng-voice.com
Office +49 40 5247593-0 Fax +49 40 5247593-99
Sitz der Gesellschaft: Hamburg Registergericht: Amtsgericht Hamburg, HRB 120189 Geschäftsführer: Carsten Bock Ust-ID: DE279344284
Hier finden Sie unsere handelsrechtlichen Pflichtangaben: http://www.ng-voice.com/imprint/