A session border controller (SBC) is a layer 7 firewall that helps your main servers by blocking useless traffic.
The SBC (also known as SIP Proxy Cluster) could be in load-balanced or high availability configuration. This depends on the business need and the kind of carrier you are using. Some carriers do no support anything but a raw IP, there are others that give the option to do a simple round-robin and there are others with more advanced features that allow balancing from the SRV DNS records.
The SBC cluster add-on will get all the incoming calls (usually port 5080 in FusionPBX) and if the traffic is valid, it will forward to the main SIP servers (that may be configured as a cluster). Because this add-on shares the same database with the main FusionPBX servers, it is aware of the configured DID and where the users are registered. Then, it can do an educated guess and forward the traffic to the right server, this means faster communications and less overloaded servers.
Since the recovery time of this clustering scheme is long comparing to others, this is ideal if you:
If you need any of these configurations in your own servers, please contact us. We will be more than happy to assist you.
However, OKay presents another affordable option. Just pay the rent of the servers and OKay will do the chosen configuration for free. All the servers must be under OKay's infrastructure to take advantage of this deal.