Carrier Class Wireless Mesh Application for VoIP

By its architecture and topology Wireless Mesh can handle carrier class services; however, when adding and application like VoIP downtime is not an option and requires fully redundancy. Feb. 2008 I attend Toronto Asterisk User Group (TAUG) meeting. And out of the meeting was to provide a rudimentary fault tolerant system that could provide 5 9’s i.e. 99.999% uptime for Asterisk Telephony solution. Now if you have read any of the previous blog articles you can see that putting in application like Telephony into a wireless mesh will not make the application automatically fault tolerant.

The application it self requires to have some redundancy. During the meeting I was introduced to three open source products:

• Heartbeat application from www.linux-ha.org
• csync2 from oss.linbit.com/csync2/(for cluster replication
• OpenSER from www.Openser.org a loading balancing device for SIP calls

The product from OpenSER is amazing if you want to have a complete load balance fault tolerant system that can handle 5000 simultaneously this is the product. However for mesh network the Heartbeat application and csync2 application can be used for a host of different product and it is not only design for Asterisk solution using Linux but any Linux solution.

Linux-HA Heartbeat provides sophisticated high-availability failover capabilities for Linux platforms. How it works is that you have two devices that you synchronized together using csync2. This creates the master and slave of the two applications that sit on two Linux boxes.

Now Heartbeat application creates a unique IP address for the two boxes. Which everyone is the master the IP address is assign, in the event of that the master loose connectivity the IP address is reassign to the slave box. To see the actual presentation Check out TAUG will give you a better explanation.

Nevertheless both heartbeat and csysnc2 are pretty good products that can help any Linux application become fault tolerant. However, modern solutions are to have high availability load balancing with no single point of failure. For building such system check out the OpenSER.