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Quick Retry: Per Request Route Optimization to Reduce Video Rebuffer Rates

A slow response can wreck an otherwise perfect video playback experience.  At least, that is what data shows when it comes to streaming high quality video content to any device, anywhere in the world.  While there is no way to control when a slow response will happen, Akamai can offer an alternative when it does.

WHAT WE'RE ANNOUNCING

Akamai is excited to announce the release of a new standard feature for our core Media Delivery product, Adaptive Media Delivery.  We are calling this new feature "Quick Retry" and it does just that. It detects that an expected response for a user request is taking too long and quickly retries the same request over a different route.  This is especially useful where there is a higher likelihood of variability in peering, congestion, and other negative networking conditions between the end user and the origin or cached file.

Quick Retry has been proven to help customers that see higher incidents of rebuffer rates and abandonment from their end users.  Often these events are caused by a video segment taking too long to get to the video player. When this occurs, the video segment is re-requested.  However, this re-request can often take longer than the available buffer in the player. When this happens, the video player runs out of video segments to play and stops playback, impacting the viewer's experience.

Quick Retry takes into account the bitrate of the stream and the available bandwidth and then retries the request for the "missing" video segment before the traditional connection timeout.  Not only is Akamai proactively sending a new request before a rebuffer event, that request is sent over a different route that is intended to offer greater throughput, reducing the likelihood of a slow response.

RESULTS

Customers who implement Quick Retry can see a reduction in rebuffer rates by 15%.  The amount of reduction will vary by use case and situation, but is correlated with what we define as slow connections (connections by default we categorize as under 5mbps).  The higher the percentage of slow connections, the more impact Quick Retry will make. Akamai generally sees a 10% decrease in the number of slow connections when Quick Retry is enabled.  This correlates with a reduction in rebuffer rates for those that gained increased throughput.

Quick Retry shines in helping improve the video playback experience for the bottom 5% of your user base who have slow connections.  It is important to note, these connections are not necessarily "last mile" connection issues, but issues upstream from the end user, generally with ISPs and peering, what we call Middle Mile.  Quick Retry is designed to overcome these transient issues. It detects the slowness at a per request level, something we don't see with traditional routing which can take much longer to detect and redirect due to congestion.  We see Quick Retry making the most impact in overcoming networks and geographies that have high congestion or traditionally bad peering. By enabling Quick Retry, greater throughput is realized for those end users resulting in fewer rebuffers and a better playback experience.

ENABLING

Enabling Quick Retry is a simple self service procedure that can be performed in Property Manager within the Adaptive Media Delivery Property.  

To add Quick Retry to the property, click on "Add Behavior" in either the default rule or a custom rule that may have been created for the video segments.

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Search for "Dynamic Throughput Optimization" and add the behavior to the rule.

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To leverage Quick Retry, simply enable the behavior and activate the config in Production.

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Quick Retry' will be used only when a slowdown is detected.  One of the best ways to measure success of the feature is to look at player side analytic data for "rebuffer events" before and after the feature was enabled.

SHOULD I USE IT?

There are some scenarios where one should be cautious about enabling Quick Retry.  Most importantly, Quick Retry can increase origin traffic and should not be used when an Origin is already at or near peak load.  Adding Quick Retry could exacerbate the issue. 

If enabling Quick Retry does not yield satisfactory results, please reach out to your account team.  There are additional adjustments available in the Quick Retry behavior that Akamai's Professional Services team can help tune and adjust for you.  

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