Lync Recording Highlights: Load Balancing and Compliance Blocking

By April 14, 2014 August 3rd, 2017 No Comments

Microsoft Lync 2013This week we would like to focus on two features of our Lync Recording suite, one that solves a technical challenge and another one that solves a legal requirement for our customers. Load Balancing provides dramatic availability and scalability potential, while Compliance Blocking allows you to block calls if recording is not available for any reason.

Honestly, our Compliance Blocking almost became unnecessary by the time we were ready with Load Balancing… all jokes aside, let’s see how these work.

Compliance Blocking When Lync Recording is down

If you are legally obligated to record phone calls, you want to make sure all calls are actually recorded. In our trading room solutions it is a standard feature to show the status of the recording system on the phone. Traders are not allowed to make calls when recording is not available in order to stay compliant.

With this feature, we are bringing Compliance Blocking to Microsoft Lync. Our Lync filters (the ones that are coordinating recording on the Lync Front End servers) are constantly monitoring the health of all Verba Recording Servers, and if no servers are available for any reason, or all servers are overloaded, a new call that needs to be recorded can be automatically blocked. Non-recorded calls are not effected by this solution.

Load Balancing for Lync Recording

The central part of this solution is the routing intelligence we are placing into the Verba Lync Filter, that is installed on all Lync Front End servers. It makes decisions about how each call should be recorded.

Let’s take a look at what the Lync Filter does to give you high scalability, redundancy and low impact on your network and Lync traffic:

  • scalability – recorded calls can be sent to as many Verba servers as necessary, their performance is added up (a typical server will handle at least 400 simultaneous calls, load balancing will multiple that with the number of servers)
  • redundancy – since multiple recording servers are participating, the loss of one server does not lead to recording outage (the filter will watch all recorders and will send recording traffic only to healthy servers)
  • geographical routing – this will help you make sure your calls are not travelling long distances just to get recorded, you can send calls to recorders placed nearby

This last point is worth more explanation.

Geographical routing of recorded Lync calls

When you are using our proxy recording technology, the media streams of your Lync calls are directed towards Verba recording proxy servers. It very important to minimize the distance this redirection adds to the travel of your calls.

Think of a scenario when calls inside a New Zealand office campus and are sent to proxy servers in Europe, just to get recorded. An Auckland – London trip takes 60 milliseconds even for light. It will take considerably more time for a  data packet that although travels almost at the speed of light, enters and exists many switches, routers along the way each adding buffering and processing times to the latency budget. The more hops the higher the chance of packet loss along the network. Many hops also lead to higher jitter, which increases the necessary length of dejitter buffers in the audio codecs on both sides.

To cut a long story short, call quality will seriously suffer if your voice needs to do the Auckland – London trip twice to reach your colleague in the next building.

By installing a Verba recorder proxy in the same office, in Auckland or even in the region (say e.g. Melbourne), you can improve voice quality dramatically.