3 Key Steps to Make Your Multi-CDN More Resilient

A top priority for many companies these days is ensuring users can access their content - especially video content - quickly and easily. And with people depending upon streaming for the foreseeable future, whether for video calls or entertainment, it’s more important than ever that the live-streaming experience is seamless. This requires a well-managed, resilient multi-CDN setup.

In a recent panel session for Content Delivery Summit 2020, NS1 Principal Engineer James Royalty and fellow panelists provided insights on how to ensure your multi-CDN is built for success. View the replay of QoS Management CDN Switching below, or keep reading for a few things to keep in mind.

Prepare for Periods of High Demand

Given changing consumer behaviors due to the pandemic, demand on your network may follow different patterns than in the past. Additionally, most events will be held virtually and attended via live stream for the foreseeable future. It’s therefore crucial that your infrastructure is prepared to handle high volumes of traffic and unexpected spikes.

When it comes to managing live-streams, the panelists provided some guidance to make sure your event is successful, such as:

• Test for every possible scenario before the event
• Specifically, inspect load testing at the authentication point to ensure your site can handle high traffic at time of sign-on
• These days, multiple parties are typically involved behind the scenes for a live-streamed event. Make sure you have clearly defined decision-making pathways going into the event.

Evolve Your Traffic Steering Policies

You likely already employ traffic steering policies to manage your multi-CDN setup. For a truly seamless user experience, however, there are more sophisticated traffic steering policies to employ. For example, you may be using brute rankings of your CDNs based upon commits, location, and performance. However, utilizing bands in your traffic steering can be more effective.

With bands, you set a range of acceptable performance for a CDN. when a CDN drops below your preset acceptable level, it’s removed from traffic steering options. Additionally, CDNs with acceptable performance will continue to receive traffic, even if there are other endpoints performing better. This avoids overwhelming your best performing CDN with traffic. It can also prevent flapping, which results in a better user experience. Intelligent traffic steering solutions like Pulsar provide a “point-and-click” interface to set up more complex policies like bands.

Track Key Metrics and Iterate to Improve Performance

Similar to the other parts of your business, deciding which metrics to track and benchmarks to set is a key way to improve the performance of your CDN. There are a variety of metrics to choose from, especially if you use an intelligent traffic steering program like Pulsar, which offers rich performance data. Royalty thinks that while the metrics most valuable to you depend upon your specific use case, he does recommend keeping an eye on the following:

• Availability for a specific CDN and region
• Re-buffering - is the issue widespread, or contained to a specific CDN or region? Is it resulting in a temporary degradation in quality, or a drop-off altogether?
• Shed - how are your traffic steering policies affecting shed? His recommendation is to slowly shed user traffic to a higher performing CDN, rather than an abrupt redirect of all traffic.