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).
You can share the dialog state between 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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