Taming the Video Beast
It was not that long ago when the notion of video occupying 50 percent of mobile network traffic seemed absurd. Today, it is the reality, and no one is surprised as that number continues to rise. Strategy Analytics (strategyanalytics.com) estimates that video, which accounted for 1.5 exabytes of data on mobile networks in 2012, will grow to 8.6 exabytes by 2017.
Though lots of high quality video streamed to millions of mobile devices is the new norm, consistently great user experiences can be evasive. Mobile operators are racing to add raw capacity and evolve networks in efforts to keep up with demand, but problems persist.
There are operators finding ways to keep pace. They’re getting smarter about how video behaves on mobile networks, where the pain points are, the impact that video has on other mobile traffic, and understanding how to best manage it all.
It’s a Jungle Out There!
Despite remarkable efforts and expenditures, one part of the network that remains a major bottleneck for traffic is the cell. The cell endures constant chaos with every session competing for bandwidth. Available capacity fluctuates constantly, by as much as 50 percent within just a few seconds. When subscribers enter a cell from the edge of its service area, signals strain to reach them and there is increased crosstalk interference. Similar repercussions ensue when subscribers move within a cell. And variation of demand can be even more sudden and dramatic than variation of capacity.
The dynamically changing capacity coupled with the dynamically changing demand placed on the cell results in inconsistent Quality of Experiences (QoE) that quickly becomes unacceptable for users.
Serving video in an environment like this is especially problematic given the performance needed for video to look great on a user’s device. Video tends to produce substantial and sustaining traffic increases. If just a few packets drop, it can degrade or halt a video stream. When it does, perception by the user is practically instantaneous.
Besides more raw capacity, another approach to coping with rising demand is deploying optimizers with a blanket rule to throttle down video bitrates. The theory is that this will result in less congestion and resolve video stream interruptions. But the other data sessions in the cell will sense the freed-up capacity and will tend to use the available resources, resulting in continued congestion issues.
This is not to say that the approaches mobile operators have taken to accommodate more traffic like video in the network have been for naught. But they do generally ignore a couple of major issues. First, most sessions run without congestion concerns much of the time. Secondly, in areas where congestion rises, that’s a factor of all traffic not just of a particular type of service. It’s both too little and too much to just try managing video sessions alone. It’s unwise to do so without perspective on which sessions are impacting QoE.
Survival of the Fittest Isn’t the Best Solution
So what is the solution? Mobile operators are working with a new class of product, the edge application controller, which is helping them get smarter about what is happening in each of their cells in real time. The key is to assess congestion and contention moment-by-moment, take action only when required, and also to manage all of the sessions in those cells -- not just video. The edge location, between the core and RAN, is an aggregated point to handle thousands of cells in a scalable fashion, while providing crucial cell-by-cell perspective on where congestion occurs and how it’s comprised.
Using edge application controllers, operators gain new visibility into how web browsing, streaming media, file downloads and other types of sessions are contending in cells in the network. They’re learning how much bandwidth these sessions are asking for and what happens to the subscriber experience when it is allowed or reduced or delayed. During congestion, bandwidth is reallocated in a way that ensures all users in a cell have the best possible experiences.
If a video stream is about to drop in quality due to cell congestion or a browsing session is about to stall from high latency, bandwidth can be dynamically reallocated. Or if there is not enough bandwidth to serve the bitrate requested by a certain video stream, a lower bitrate can be requested instead to ensure the user gets a good viewing experience versus staring at a buffering message.
When bandwidth “hogs” congregate in a cell, a few users may crowd out small, quick sessions resulting in a bad experience for many by trying to protect the experiences of few. An edge application controller can assess live intelligence about all of these sessions and their impact on the cell, in order to ensure minimum bitrates for browsing and applications and smooth streaming of video and other types of content.
Notably, during periods and in locations of non-congestion, operators using edge application controllers can choose a hands-off approach, allowing video and other traffic to flow through the network at the bitrate requested. From a user experience standpoint, this provides the fastest and highest quality experience. And the cumulative delivery of more content can enhance operator profitability.
Scaling networks in just a few short years to handle more than 5 times the data usage certainly poses a challenge, though not an insurmountable one. Mobile operators will meet demand not just by building more capacity, but making the most efficient use of the networks they already have. Maximizing efficiency will mean always being smart about what is happening in every cell at every moment to only take action when and where needed. It will also mean managing all traffic in the network, taking advantage of the differences in their delivery needs, and not just focusing on improving performance of one particular session type.
Armed with emerging tools like edge application controllers, mobile operators will bring order to their networks and deliver superior experiences, every time.
John Reister is vice president of marketing and product management for Vasona Networks, helping to drive the company’s collaboration with mobile operators to reduce cell congestion and deliver better subscriber experiences. He has more than 20 years of experience in video, broadband, and mobile networking. For more information, email firstname.lastname@example.org or visit www.vasonanetworks.com.
What’s your take on this subject? Leave a comment and get the conversation going.