Time to cache in

13th June 2003 at 01:00
Using the internet can be a frustrating experience. Even with a high-speed broadband connection, internet traffic can be sluggish. And as Alan Teece, director of Granada Online Learning, points out: "Regardless of how much bandwidth you have, it will never be enough. As soon as you get a high-bandwidth connection to the internet, more people use it." Motorways are a good analogy - even if they are widened, they soon get clogged up with more traffic.

But there is a solution - web caching. At its most basic, a web cache is a vast store that holds content like web pages and files downloaded from the internet. It is also connected to a school's network.

A major benefit of using a cache is that pupils can access web resources directly from a cache rather than having to go online to a website. This provides much faster access and also frees up the bandwidth on your internet connection. It means that before the start of a lesson, a teacher can go online and download all the web resources needed by the pupils beforehand. Caching is also a lot cheaper than investing in more bandwidth.

The Department for Education and Skills is keen for schools to invest in web caches, especially those currently without a broadband connection, and has made funds available. But Rebecca Thomas, RM's senior manager for caching solutions, says: "A cache is also an important complementary technology for schools with a broadband internet connection."

There are two types of caches. Edge caches operate at the edge of large networks, such as those run by Regional Broadband Consortia and local education authorities (LEAs), and store web content and resources that can be accessed by schools connected to the network. Standalone caches are individual units linked to a school's network.

Companies such as Cisco and RM already produce caches and will soon be joined by Microsoft and BT; prices start at about pound;1,000. RM's product, SmartCache, also has optional modules for tracking internet use and filtering.

Teece divides caches into three groups. Reactive caches store content as a result of web usage. For example, if a pupil goes on to the BBC Bytesize website, the cache stores its pages and the next pupil to use Bytesize gets the resources from the cache rather than the web.

Proactive caches allow users to enter addresses for sites whose content they want to store. Users can specify the level of content they want to find and save, the first 20 pages on Nasa's site for example.

And there are content distribution caches, which allow commercial software publishers to download content on to a school's cache.

Steve Creed, head of ICT infrastructure technology testing at the British Educational and Communications Technology Agency (Becta), says: "If you want to buy a cache, consult your LEA or regional broadband consortium first to ensure they are compatible." This is because the networks often use hierarchical caching, whereby content is passed from one cache to another before it reaches that of a school. You should also ensure the cache is compatible with your network and its internet connection.

Web caches offer many different features. For instance, some will automatically change a web page whenever it is updated. Others will delete content after a specified time. There are so many variables Becta has begun to set minimum standards for web caches to cover issues such as compatibility, interoperability and content handling; draft recommendations include a minimum storage capacity of 70Gb, an ability to handle many types of data files and streaming media, and compatibility with content packaging systems, such as that of Curriculum Online content.

Some manufacturers, such as RM, claim their products already exceed the standards, but Teece says: "I would suggest schools hold off buying while the standards are being finalised. Otherwise, get a written commitment from the vendor that they will upgrade the cache to the new standards."

Becta: http:getconnected.ngfl.gov.ukinfoindex.html

RM: http:demo.smartcache.rmplc.co.uk

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