Desktop video conferencing has always been a case of two halves. For every benefit to intra-company communication, there seems to be a technical limitation threatening the stability of the network. With this fact firmly in mind Ben Burns, Solutions Lead, EMEA at MASERGY, examines the benefits of SVC-Optimised QoS.
Issues like packet loss have also long plagued video conferencing deployed over non ideal networks. That is why IT teams seek alternative means of deploying intra-corporate video.
One common counter-solution to solve network congestion is adding more bandwidth. This risks increasing the volume and management complexity of network traffic without addressing the causes of congestion. A second method is to deploy scalable video coding (SVC) technology to combat latency and packet loss.
What is SVC?
Put simply, SVC is a layered video codec extension of the established H.264 standard. SVC transmits both a base video layer and one or more enhancement layers to improve video quality up through high definition. This layering technique allows for a certain percentage of packet loss while maintaining the video stream, thereby all but eliminating artifacts or pixels.
What this means is that SVC can allow for multiple clients with different capabilities to receive the same video signal without the need for further encoding. As a result, a single SVC-encoded stream with different receivers who have various capabilities can decode the necessary layers to produce an image from standard definition through to high definition. This greatly reduces encoding latency and the overall computing power that is required.
For enterprises looking to deploy desktop VC on a wide scale, this offers an interesting option. Users can experience high quality calls without the need to pay private network prices. Unlike traditional HD video calls, SVC does not experience significant lag. Instead the definition of the call constantly varies in quality, fluctuating between high and standard definitions depending on network congestion.
Managing an SVC-based desktop video implementation
While easy to see the raw benefits of SVC technology, deploying video on mass can still prove difficult. A carefully considered method is required to ensure access to critical business applications is not inhibited.
This can create an inverted video QoS paradigm where any sizable desktop video deployment, if implemented over standard WAN, can overwhelm the network. So, instead of protecting the video application from other corporate traffic, the opposite occurs; other corporate applications need to be protected from the video application.
A unique approach
A native MPLS network for intra-company data communications with Intelligent QoS allows for the prioritisation of essential voice and video applications and prevents the inverted QoS problem from occurring.
In the past, the emphasis has typically been on the guarantee that critical applications should perform while the remaining traffic should fall into an unmarked or best effort queue. While internet traffic is not marked, companies still rely on consistent access to the public Internet for daily operations. Avoiding this dilemma can be challenging and requires a specific solution.
With most WANs, the majority of traffic is marked as undifferentiated data and their type of service (ToS) precedence value is considered to be 0. Commonly traffic of this type is referred to as best effort and not given special treatment over the WAN. However, that doesn’t mean it should be ignored. Much of the best effort traffic is still of tremendous value to enterprises and it often requires a minimally acceptable level of throughput and performance.
By utilising a limited plane class of service (CoS) that deliberately de-prioritises below best effort, users can maintain bandwidth hungry video flows without the fear of overloading the network. A limited plane that services at a lower priority than normal data is also ideal for data back-up or packet-loss-tolerant applications such as SVC desktop video.
Its inherent resilience in the presence of packet loss means SVC-based video can cope with the variable network conditions it encounters on the least effort plane of service.
Recognising the Future
Even with the above addressed, issues of security, scalability and performance can still remain. With a native IP multi-protocol label switching (MPLS) network, enterprises can operate desktop video at varied security levels - running one VLAN publically and another privately for example.
Furthermore it is possible to use a Limited Plane on both VLANs to provide users with higher security requirements the option to use a private network. This prevents exposing video communications to the public Internet and the potential security risks that come with it. In essence, it removes the need to encrypt intra-company calls and as a result reduces network workload and management.
Using a Limited Plane lets users select which SVC-based calls can run at a higher QoS level. Intelligent service control with QoS-enabled service scalability is perfect for adjusting bandwidth at a moment’s notice. It can dynamically allocate bandwidth between public and private services based on the traffic’s QoS tagging.
Facilitating the adoption of a new communication technology while protecting higher priority applications on the corporate network is always going to prove difficult, but a solid CoS enables enterprises to manage and protect their network while looking to the future.
The advantages are clear. Possessing the flexibility to run public or private networks on a single circuit with built-in security for private intra-company communications is a powerful tool. The ability for VC applications to perform without affecting the network’s performance is crucial for business. Ensuring that you can offer staff high-definition video capabilities without a disruption to your network is only possible with advanced QoS capabilities.
Understanding this need and implementing a solid plan is vital to the future of your network. Only when this is understood does SVC yield its full potential. By combining intelligent network management with SVC technology, you can successfully address the issues that have long prevented large scale VC rollouts.
