VoIP Failover with Xorcom Twinstar

October 29, 2010 by Garrett Smith

Introducing Twinstar…what do you know about Failover!!!

If you are new to the VoIP game or are a seasoned veteran, we all know that in business…we need to be able to make and receive phone calls. Most businesses rely on this type of communication to handle the day to day business activities. Also, it is required in most cases of an emergency.  With the introduction of IP PBX’s and VoIP, we all know that there are great ways to reduce costs as they relate to your recurring  traditional phone “bills”, but what happens if your  IP PBX decides it wants to crash and fail. In either case, this is a recipe for disaster. What if you can’t make phone calls? Can you run your business? How much down-time can you afford? These are all questions you must ask yourself and consider when deploying a VoIP solution…because these are all very real scenarios that have happened and could happen to you, that is, if you don’t protect yourself.

Recently, I had the pleasure of attending a Xorcom hands-on technical training in Las Vegas, NV. Yes, I actually did pay attention in class and wasn’t distracted by those chirping slot machines just a short walk down the hall. If you don’t know of Xorcom, or they are new to you, you can find more information about them here.

During the training, Xorcom demonstrated the 1st 100 percent reliable complete failover solution, they call Twinstar. Twinstar is Xorcom’s method of delivering a complete failover solution without any personal involvement. That means that you don’t have to get out of bed at 4am to cater to an alarm that your IP PBX is having issues. Rest assured, with the solution below, you will be 100 percent covered when it comes to making phone calls. Trust me, I seen it in action and you will too.

The Xorcom Twinstar solution comprises of (3) required hardware components and (1) software requirement. First, you need to have the following:

A Xorcom Astribank. An Astribank is a USB peripheral device that connects to the PBX via USB. The Astribank will allow your VoIP solution to connect to the outside world, either via FXO PSTN, or Digital T1. The Aastribanks are modular and can support PRI signaling either via T1 or E1, and FXO/FXS PSTN RJ-11 connections. You will want to ensure you also suit your Astribank with the dual USB ports for Twinstar failover Support. You can check out the lineup of Astribanks here.

(2) Xorcom XR2000 or XR3000 IP PBX’s. Xorcom manufacturer’s three models of IP PBX appliances, two of which are suitable for Twinstar failover. The Xorcom XR2000 appliance supports up to 200 users, 60 concurrent calls, with 1GB of RAM and optional RAID support on its hard drives. More details on the XR2000 can be found here. The XR3000 is Xorcom’s “big daddy” server that can support up to 1000 users, 300 concurrent calls, with 1GB of RAM with the option to upgrade to 4GB, optional RAID support on its hard drives, and an Intel Core 2 Duo processor with the option to upgrade this as well, to a Quad Core processor. More information on the XR3000 can be found here.

Xorcom Twinstar LC0016 – This ensures your Astribanks come with the required 2ND USB Port and necessary USB cables to connect to your Xorcom XR PBX, to support Twinstar. This also ensures your Astribanks come with the necessary firmware to support Twinstar.

Complete PBX or Xorcom’s Elastix based Software– Lastly, in order to take advantage of the Twinstar failover solution, both XR appliances must be pre-loaded with Xorcom’s Complete PBX or Xorcom’s Elastix based software. The Elastix-based software is free of charge. The Complete PBX version is paid commercial software developed and offered only through Xorcom directly. When you are talking to your VoIPSupply sales rep, tell them that you want either Xorcom’s Elastix based software or their Complete PBX software loaded. If you would like the Complete PBX software, we can have a Xorcom representative contact you immediately after your hardware purchase through VoIPSupply to discuss pricing and feature support.

Now that we have covered your hardware and software requirements, let’s talk about how the solution works.

Step 1:

Let’s start with the Astribank suited for twinstar failover with dual USB ports. You will first connect your PRI (T1/E1) connections, PSTN RJ-11 FXO connections, and any analog telephones to your RJ-11 FXS connections on your Astribank. This will satisfy your means of making and receiving calls to and from the outside world.

Step 2:

Setup both of your XR servers whether they are the XR2000 or XR3000 with the SAME IDENTICAL ASTERISK CONFIGURATION. No my caps lock is not stuck. This is very important as it relates to the failover portion. Remember, your XR servers will need complete PBX software. Once you have loaded the identical configuration to each server, you will want to designate 1 server as the Primary server and the other as the secondary. Both servers will be on and running simultaneously, but we need to tell the Astribank which one is live (primary) and which one is the backup (secondary). Also, keep in mind, when you make an asterisk configuration change on the main server, you will want to copy or replicate those changes to the secondary server. You should do this daily as you may never know when an incident or problem may happen. You can do this via DRBD Synchronization. More on this setup can be found in the technical guide linked below.

Step 3:

Connect your primary XR server to the Astribank’s USB (MAIN) Port. Then connect your secondary or backup server to the 2nd USB Port or the (BACKUP) Port as pictured below.

Now that we have gone through steps 1-3, your hardware solution should look something like this:

Step 4:

OK, now this is where the configuration may get a little technical. Within the asterisk configuration, you will create a cluster IP address that encompasses both of your XR servers. For instance, my primary XR server’s IP address will be, my backup XR Server will be and the cluster IP address will be The cluster IP address encompasses both XR servers which you will use to register your IP Phones to. This allows your IP phones to easily failover if a problem is detected. I am aware of certain IP Phones support a backup SIP server option in their configuration but not all manufacturers do. In the twinstar failover solution, you can use any IP phone you want, just ensure you register them to the cluster IP address. Here is a small look at this setup:

Step 5:

Test the Twinstar Failover solution- Once steps 1-4 are complete and you are properly making and receiving phone calls from your IP phones or analog phones connected to Astribank, pull the power plug on your primary server. This will cause twinstar to take action and immediately failover all connections including PRI (T1 or E1), FXO or FXS, SIP Trunks, and your SIP phones to the backup server. This failover switch takes about 10-20 seconds to complete but requires no unplugging and movement of cables or equipment. After the switch, you are now back up and running on a fully functional phone system identical to the one that just failed without a hiccup…well there is one hiccup, if you were on a call during that transition to failover, your call will be dropped. This is next step for Xorcom, to achieve, a fully redundant failover solution without any in-call interruptions.

And that’s how the most reliable failover solution works… Below is a link to a short video presented by Xorcom that describes in a nutshell the twinstar failover solution described above.


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