When using a video collaboration application the end user only cares about the quality of their experience. Part of that experience is determined by the audio and video quality people receive during a meeting. Network performance is a key component of that quality. In this article we will look at some of the things to consider when network planning to help ensure best performance.
Bandwidth is definitely a friend when looking to deliver maximum audio and video quality. The more bandwidth you have the higher the video resolution and frame rate you can transmit and receive. In the past that has typically meant requiring dedicated IP video networks, separate from a company’s traditional data network, so that the appropriate bandwidth and prioritisation could be applied to the video traffic. This separation would help ensure that the video traffic could be controlled and managed without affecting and being affected by other data traffic. It goes without saying that this separated approach would always add both to the cost and complexity of any video deployment.
The good news is that there have significant improvements in the underlying video technologies over the past few years that help reduce bandwidth requirements for video collaboration as well as making video traffic more robust in less than perfect network conditions.
Back in 2010 Polycom was one of the first organisations in the collaboration industry to start supporting H.264 high profile (H.264 HiP) video compression. This video compression standard enables organisations to reduce their bandwidth requirements for a video transmission by up to 50%. To put this in perspective a 720p resolution video connection at 30 frames per second (fps) would typically have required at least 1Mbps of bandwidth for a successful connection. With H.264 HiP the bandwidth requirement is now only 512Kbps. This means that organisations can now double the number of video connections across a network link without having to pay for extra bandwidth. In addition this has also opened the door to a significant improvement in the remote / teleworker experience. No longer does a remote user joining from a home office have to be the “poor cousin” of a video meeting with grainy resolution and low frame rate. H.264 HiP enables any user with a reasonable broadband connection to achieve high quality results.
In addition to reducing the bandwidth required for a video connection there have also been some significant improvements in the underlying transmission technologies to help try and maintain video quality even when the network conditions are less than perfect. One key development in this area is error correction. Robust correction algorithms have been developed which use methods such as forward error correction to help maintain quality of the video stream. What this means in practice is that if some video packets are lost during transmission due to network issues there is still sufficient redundant information available in the remaining packets for the video transmission to be reconstructed. As an example Polycom’s patented Lost Packet Recovery technology has been shown to create a ‘no loss’ experience for packet loss up to 2% and only a minor video quality impact with 5% packet loss. Even with 10% packet loss Polycom LPR was shown to provide an “acceptable user experience”. (For more information on Polycom LPR and independent test analysis please download the white paper from our web site: Lost Packet Recovery White Paper).
2) Data prioritisation across networks
Bandwidth efficiencies and packet recovery technologies have delivered great benefits to organisations and enabled them to run more video calls on their networks, as well as deliver video across networks that potentially could not have supported it in the past. However it is still important that corporate video networks are designed appropriately to cater for the high bandwidth, real time traffic that video collaboration generates.
Quality of service (QoS) markings are an obvious tool for helping ensure video networks handle video traffic appropriate. Just about every video collaboration manufacturer now ensures that both their endpoints and video infrastructure can support appropriate packet markings to allow a routing infrastructure to be able to apply appropriate prioritisation of traffic across a network. A holistic view of network design should be taken to ensure end-to-end quality preservation through the whole network path. Juniper Networks has some excellent resources on network design for conferencing and collaboration, including this comprehensive white paper: Simply Connected for Unified Communications and Collaboration (UC&C) Reference Architecture
3) Intelligent network integration
It is now possible to go much further than simply an appropriate QoS design for a video network and look at an intelligent video network that can deliver quality assurance. QoS has typically been a static environment where a network designer assigns appropriate service levels to different traffic types and then the traffic is handled appropriately. This prioritisation was typically static and preconfigured and couldn’t account for network variations. Some routing & switch manufacturers have then taken this concept further and have developed more dynamic queuing mechanisms that can alter priorities based on network conditions and historical data. However these solutions often simply work by allowing a traffic type such as real time video to sporadically burst above a pre-defined level. This approach doesn’t guarantee quality and can put other application traffic at risk.
Polycom and Juniper Networks have partnered to go one step further to create a truly application aware network environment. Real-time video network infrastructure resource controls are enabled by the integration of the Polycom® Distributed Media Application (DMA) conference platform and Juniper Networks Session Resource Controller (SRC) Series. This allows the network to respond dynamically to the needs of the video service and makes network policy changes in real time to ensure that every communication session goes through the network with the expected level of quality. When a user places a video call from their desktop application, conference room, or immersive suite, the call is routed to the Polycom DMA platform supporting the video network. The DMA then interfaces with the Juniper SRC Series policy manager to correctly provision all the devices on the network for adequate bandwidth to accept the call and deliver it with assured quality. All this occurs BEFORE the call acknowledgement and authority to connect is granted by the call control function. This enables the joint Polycom / Juniper solution to deliver higher network scalability, service reliability, and reduced day-to-day network administrative requirements for video services. A more detailed description of the call assurance that this integration delivers can be found in this Juniper paper: Network Configuration Example Configuring Assured Forwarding for High-Definition Videoconferencing
4) Bandwidth performance & analysis services
Not all organisations may have the skills in house to create a detailed real time video network infrastructure. Other organisations may already have a network in place but be unsure of quite how the network will react to the load of real time video traffic. To help in both these scenarios there are now a number of professional consulting services available from Polycom and others to help with the design and planning of video networks. As an example, Polycom has both video network readiness assessment services as well as video solution design services available to assist customers with planning and implementation. These types of services can help an organisation understand the current capability of their network environment, identify any solution interdependencies before a deployment starts as well as create a unique solution designed specifically to meet the customer requirements. Whilst these services do require upfront investment experience has shown that these professional services save time and money in the long run by reducing the solution implementation time and minimising the implementation risks, thus ensuring the operational benefits are realised earlier.
5) Network to Network boundaries
Most video network designs focus on what happens to the traffic within an organisation. When that traffic leaves the network boundary to connect to an external third party, or if a remote user is connecting from home into a corporate conference then the section where the traffic is off-net has no quality control. QoS markings are not typically carried across from side of a network boundary to another so the quality of traffic from that home user looking to dial into the corporate network is usually in the hands of “the internet gods”.
The good news is that there are now initiatives under way to help create more coherence across the network boundary and help create a consistent assured video experience, even for traffic that might cross multiple network segments. One such independent organisation driving this initiative is the Open Visual Communication Consortium (OVCC). The OVCC was established to bring manufacturers and network providers together to help create a seamless video service delivery across multiple carriers and equipment providers.
From an end user perspective the key benefit that will arise from initiatives such as those being driven by OVCC others will be the confidence of an end-to-end quality video experience. The video call might start on a device from one manufacturer, cross multiple network boundaries via routers from different manufacturers and finally terminate on a video device from a different supplier. If all the solution components and network providers have built their solutions in line with the specifications being developed then that call will have been delivered securely over a known network with proven processes.
What this means from a real world experience is that you can take a tablet or smartphone, laptop or dedicated video device, connect to a 4G cellular or reasonable broadband connection, and have a good chance of success of an effective video conference.
The bottom line is that effective network design, suitable advance planning and application aware networks, along with global initiatives that involve the network service provider will lead to an outstanding user experience - each time, every time.