The challenge of satellite communications

Calnex was commissioned by one of the world’s largest defence manufacturers to ensure its state of the art battlefield control software would deliver for end users across satellite links. This organisation had to adhere to stringent end-to-end service level agreements under all possible field conditions. The Calnex Network Emulator unit was employed to rigorously test and troubleshoot critical application performance in an emulated network environment prior to release. Conditions such as limited bandwidth, high latency and data loss were injected onto the test LAN, with measurements taken of how the battlefield control software reacted. This visibility allowed the application team to implement targeted software optimisation before release – dramatically reducing costs and ensuring an on time release to the end customer.

Background Reading

Recent years have witnessed a surge in the transmission of Internet Protocol data across satellite networks. Satellites are now extensively used to carry voice, video and a significant array of data communications for thousands of organisations across the world every day.

The satellite market is on course to deliver $26 billion in satellite equipment through to 2016, and satellite communications are playing an increasingly important role in the delivery of services to end users. The global pay TV market, for example, totalled $125 billion in the first half of 2011 and is forecast by Infonetics Research to grow to $353 billion by 2015 - driven in the majority by the rise of satellite delivered IP services.

The Challenge

Satellite networks experience very long latencies and considerable data loss, as the signal travels to and from orbiting vehicles through fluctuating atmospheric conditions. These factors create major implications for the performance of critical applications including voice communications, logistical support systems, emergency service co-ordination, military control structures and so on. Those responsible for ensuring application delivery to end users over satellite links need to understand – as early as possible – what issues those applications will face, so the costs of re-work is minimal and end user performance is assured.

Ensuring Application Performance

Satellites today are used for a vast array of internet protocol (IP) based communications, from delivering business critical applications to business users, to supporting emergency service responses and military exercises. Lives depend on satellite systems being capable of providing instant and accurate information between any two required locations anywhere in the world under any foreseeable circumstances. Organisations that use satellite networks must have confidence in the systems that direct and support their operations.

These systems must be rigorously tested under the exact network conditions they must perform on - before they are deployed to those that rely on them. Satellite networks are susceptible to multiple impairments, which should be tested against before release:

  • High latencies dependent on or bit height and number of satellite hops.

  • Fading RF channel environments, resulting in significant bit error rates and bursts in traffic.

  • Atmospheric conditions such as raid fade impacting quality of transmissions.

It stands to reason that expensive field trials or deployment should not be the first opportunity to identify and resolve mission critical application performance issues caused by IP satellite communications.