How to avoid a dodgy video experience

The use of video for company briefings, team meetings and supplier and customer interactions is increasing rapidly. According to Wainhouse Research, sales of videoconferencing equipment are set to rise by an average of 21 per cent a year from 2009 to 2014. This trend could lead to increased network problems.

Video consumes large quantities of bandwidth across both LAN and WAN. The result is increased latency and packet loss, causing a degradation in performance for all applications, which is particularly noticeable for video and VoIP.

While a webconference session typically spikes at less than 1Mbit/s per user, the cumulative effect of having many parties collaborating makes for a considerable network impact. Similarly, a three-screen telepresence call requires about 15Mbit/s per site.

Fortunately, there are several ways IT departments can mitigate these threats to network performance. The most obvious – but least palatable, financially – is a network upgrade. Thorough planning of future network load, and analysis of pilot implementation phases, will identify which network links are too small to support the additional traffic. An upgrade to these links, or the installation of an overlay network dedicated to video, provides the answer.

There are neater options. Between sites, enterprises can take advantage of class-of-service offerings provided by their telecoms operator. Typically an operator will guarantee the availability of a defined amount of bandwidth for defined classes of applications. So a business could choose video traffic to be guaranteed 5Mbit/s of a 10Mbit/s pipe between office A and office B, for example. The IT director will identify which are the most time-critical applications, and ensure these are given the top classes of service. Voice and video will typically occupy the top one or two classes. On the LAN, packet tagging gives the same effect of prioritising voice and video.

Enterprises are increasingly investing in WAN optimisation appliances from the likes of Riverbed, Juniper, Cisco and Ipanema. These devices accelerate and reduce the quantity of CIFS- and MAPI-based traffic, which reduces the load on the WAN from these applications, but they are not capable of optimising video traffic.

Avoiding the pitfalls

Unfortunately there are many pitfalls IT departments must avoid in deploying video. A critical one is interoperability, which continues to dog telepresence systems, despite recent efforts to open up telepresence protocols. Service providers offering managed telepresence services offer a solution to the problem by providing a bridge between different vendors’ systems. Such managed services are also useful because they allow businesses to lease telepresence equipment rather than buy outright.

Businesses must also consider how videoconferencing will fit into any unified communications (UC) strategy they might be considering. Businesses cannot afford to invest in video infrastructure that will become obsolete when UC is introduced.

Pilot implementations are essential for projects as important as video, because they can be rolled back easily if an unexpected problem is found. IT departments must also ensure that their video network is resilient to protect against unexpected downtime.

“Standards-based and interoperable – that is the key,” says Tom Erik Lia, director of systems engineering at Cisco. “But as well, businesses must build a robust core architecture and [ensure] that their network is ready [for video],” he adds.

One business that has successfully tackled video issues is Amey, the engineering and transport consultancy. Amey has deployed videoconferencing end points at 50 UK sites, with many using trolley-based end points that connect via the WLAN. It chose mobile end points partly because users frequently disconnected its former fixed end points from the network to plug in their laptops. It also chose wireless end points so video communications could be offered in any meeting room without needing to purchase an end point for each room.

Amey did, however, have to carry out extensive network testing prior to deployment. Having done this, it decided to upgrade three links to support the extra demands of video traffic. It also chose to define two classes of service from its operator BT to guarantee the delivery of video traffic. In addition, it has carried out numerous tweaks including packet tagging to ensure the quality of service over Wi-Fi.

“QoS is a very big point of running video,” says Nathan Boatwright, senior security and systems specialist for Amey. “End-to-end QoS is the word.”

Video is a vital application for businesses. Without being managed, video traffic can cause substantial network disruption. But with the right policies and technologies in place, it can be harnessed to significantly increase employee productivity.