Thursday 24 March 2016

SaaS and Cache

Skepticism to a design that supports hundreds of users through what appears to be a very restricted bandwidth connection is understandable but it is technically possible.

Once the traffic profile is understood, its simply a question of sizing the connection correctly to meet the demands of the site. In the UK and other countries with access to a well developed broadband service the minimum connection is likely to be in the order of 50-100Mbs which commonly exceeds the average connection speeds in countries where GSfE has been widely deployed.

In the future the cost of internet access will only ever come down and once greater speeds become affordable the bandwidth objection will be irrelevant for a school of any size.

An additional aid to bandwidth control could be provided by a proxy cache, a service that was common in just about every business that used the internet in the early days when bandwidth was limited and expensive.

Over time the requirement for a local cache was made redundant by cheaper contracts and the emergence of active content but it might be time to reassess this capability particular with respect to streaming media.

Unlike most businesses, schools have a unique profile with respect to media downloads. As part of a class project or group work multiple requests for the same resource can be made within a very short timescale. This makes a school an ideal candidate for some form of local media caching service.

If a teacher pre-loads a resource prior to the lesson subsequent requests will be made from the local cache which will increase the response times, improve the perceived reliability of the service and reduce the peak loading on the internet uplink.

The service would be tightly focused on certain sites delivering multimedia curriculum resources such as YouTube and Vimeo and wouldn't provide a general caching service for other SaaS services - in fact it would need go out of its way to avoid it.

The caching of video streaming services is a specialized operation, its not as simple as writing static HTML pages to disc.

A number of solutions exist, mostly based on the open-source Squid proxy engine but nothing specifically aimed at the education market which is surprising because the traffic profile in schools is so well suited to media caching.

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