Blog | Steve Lacoff 
February 23, 2016

How Comcast’s CDN Handles Traffic Spikes

Sporting events, political rallies, retail sales, and movie premiers can all cause highway traffic jams. These same events can also lead to significant spikes in Internet traffic. And, when spikes occur, the quality of an end-user’s streaming or download experience typically suffers. Live sports and breaking news shows experience low bit rates and pixelate, online gaming downloads stall, and streamed movies buffer. Content Delivery Networks (CDNs) help mitigate the effects of these spikes and deliver a consistent, high quality experience to the end-user.

However, some CDNs are better equipped to handle these spikes. The Comcast CDN was purpose-built for large media delivery at the highest scale for live events. With more than 100 nodes and one of the largest, most advanced networks in North America, the Comcast CDN easily manages demand spikes while maintaining stream and download quality.

How does the Comcast CDN do it? Because Comcast is a video content provider and distributor, the Comcast CDN is optimized to handle this type of large file delivery and traffic surges without the degradation of quality. In addition to robust network infrastructure, Comcast employs the following strategies to mitigate traffic spikes and deliver superior performance:

  1. Continuous Monitoring – Using a variety of monitoring tools, Comcast tracks CDN performance and watches for end-user peak usage patterns. Comcast also builds robust predictive models that take into account the industry’s broader historic and forecasted internet traffic growth statistics, as well as Comcast’s own data.
  2. Proactive Planning – After assessing end-user patterns and predictive modeling, Comcast preemptively and liberally increases CDN capacity for recurring and anticipated peaks in traffic. Comcast also implements a ‘soft moratorium’ to minimize impactful infrastructure service changes if a CDN customer has a critical event on the horizon.
  3. Strategic Absorption – For unanticipated traffic spikes, Comcast absorbs the excess traffic by automatically spreading traffic to multiple CDN caches in the same metro. Comcast has over 100 separate caching locations in the U.S., and spreads its CDN traffic to multiple proximate physical locations in each major metro without a tradeoff in performance. These CDN locations are strategically deployed across the U.S., which (1) enables delivery in large metro areas and (2) more evenly spreads demand to prevent congestion that commonly impacts high throughput HD video and large file downloads. In addition, the Comcast network is well interconnected with many other networks. This enables high-quality content distribution, and allows content to be localized for distribution just as effectively.
  4. Reliable Service – Many CDNs don’t provide enough overhead capacity or standard origin protection tiers to absorb large traffic spikes. These practices further compound the congestion problems experienced during large events. Excess traffic is either bottlenecked in the CDN or passed back to the customer’s origin, which makes end-user problems worse. This does not happen with Comcast’s CDN, which has a QoS variance that is 20-30% better than other CDNs based on objective third-party data. Whether it’s serving high seasonal traffic peaks or one-time massive scale video events, content is delivered consistently to end-users and a customer’s origin load remains at an absolute minimum.

If you have media content that is prone to spikes such as movies, TV shows or online games, you will want a CDN designed to protect your content and customers. The Comcast CDN, available from Comcast Technology Solutions, offers the most complete solution that can be used as a stand-alone CDN or as part of your multi-CDN strategy. Please contact us to learn more.