News: High Availability SIP Trunking with Automatic Failover

We are excited to announce a major high-availability upgrade to our SIP trunking platform. Your voice service can now ride three independent SIP servers with automatic failover built in, so a problem on any single server no longer means a dropped trunk, a dead phone system, or missed calls. For a business, that is the difference between a hiccup you never notice and a phone outage your customers do.

Why high availability matters

Your phone line is often the most important way your customers reach you. When it goes down, orders stop, support stops, and revenue stops with it. Historically a SIP trunk pointed at a single server, which meant that server was a single point of failure. If it went offline for any reason, your calls went with it.

High availability removes that single point of failure. Instead of one server, your trunk is now backed by three. Here are the kinds of everyday events that used to be a risk and now are not:

• Planned maintenance and upgrades - we can take one server out of service to patch or upgrade it, and your calls simply run on the other two. You get the security and reliability of an up-to-date platform with no scheduled downtime for you.
• A hardware or software fault - if a server has a problem at 2am, your trunk keeps working on the remaining servers. No 2am phone call, no scramble.
• A network issue in one spot - the three servers sit on independent infrastructure, so a network problem affecting one does not take the others with it.

Two ways to connect

You now have two supported ways to point your PBX or SIP device at our network, and you can use whichever fits your equipment.

• Three independent trunk endpoints - sip-1.incentre.net, sip-2.incentre.net, and sip-3.incentre.net are three separate SIP servers, each on independent infrastructure. Your trunk configuration is replicated across all three, so the exact same trunk works on any of them. If your phone system supports a primary and backup registrar, you can point it at more than one and get redundancy right away.
• One smart hostname with automatic failover - sip.incentre.net is a single address that does the failover for you. Point your device at it and it automatically finds all three servers and uses them in order. If the first one is unreachable, your calls move to the second, then the third, on their own, with nothing for you to switch over.

How the automatic failover works

The single hostname is built on a long-standing internet standard for locating SIP servers called RFC 3263. In plain terms, when your device looks up sip.incentre.net, it does not just get one server address back. It gets a prioritized list of all three, published in special DNS records called SRV records.

Think of it like a phone directory that hands your equipment a ranked list of numbers to try: first sip-1, then sip-2, then sip-3. Your device tries the top of the list, and the moment it cannot reach that server, it moves down to the next one automatically. Because this is a published internet standard rather than anything proprietary, it works with a wide range of standards-compliant PBX and endpoint equipment, including 3CX. You configure one address, and the failover logic is handled for you.

Link to full RFC 3263 spec: https://datatracker.ietf.org/doc/html/rfc3263

How to use it

If your PBX or SIP device supports DNS SRV or auto-discovery (most modern systems do, including 3CX), set your trunk host to sip.incentre.net and leave the port on auto-discovery. Your device will find and prioritize the three servers on its own, and you are protected the moment it registers.

If you would rather manage failover yourself, or your equipment does not support SRV, you can point directly at the individual endpoints sip-1, sip-2, and sip-3.incentre.net.

What you need to do

No action is required. Your existing trunk keeps working exactly as it does today, and this upgrade is here whenever you want to take advantage of it. If you would like help moving your trunk onto sip.incentre.net for automatic failover, or you just want us to review your current setup and make sure you are getting the full benefit of high availability, reach out and we will walk through it with you.