Northern Grid for Learning - School Broadband, eSafety, Learning Resources and More

What is a Web Cache?

A cache server temporarily stores copies of web objects.  A web page is built up of multiple web objects and comprises text, images and files.  Cache systems improve accessibility and availability of web page content.  The Cache server recommended by the Northern Grid is the Cachepilot.  This is an Equiinet product and is supported by Easynet.

In addition to caching services the Cachepilot performs web based filtering, content delivery and web site archiving.  

A cache server optimises use of bandwidth.  It reduces the need to use the Internet by storing websites locally.

How will a Cache system benefit a school?

Caching minimises the number of times an identical web object is transferred from its host server by retaining copies of requested objects in a database or repository.  

Modern cache systems retain web objects or entire web sites for as long as the user wishes.  It is possible to stipulate how often the content should be refreshed to ensure that it is still current.

The LAN bandwidth is generally greater than the WAN connection bandwidth but caching can stop a bottleneck occurring by preventing identical requests for web-based objects.  A cache server has the ability to pre-cache content overnight making it available to the network for the following day.

Caches are limited in the amount of disk space available.  The Cachepilot has 120GB of storage. This is more than adequate for general use.

For more information about how to PreCache and Mirror web page content, check out this document.
The Northern Grid is able to provide training for Local Authorities and schools.  The training can be either technical or general user focused.  A charge is made for this service.  Please contact This e-mail address is being protected from spambots. You need JavaScript enabled to view it at the Northern Grid for Learning.

Advantages of Caching

Cache servers have a proxy function as they make HTTP requests on behalf of the client.  However, a Proxy server performs additional functions such as security and administration control.  The Cachepilot is a cache, proxy, firewall and filtering server.

Requirements for a Cache Server

A Cache server should be able to:

•    Be capable of performing transparent caching, pre-caching and mirroring.  

•    Act as a content delivery system and preload learning resources.  

•    Act as a node on the schools internal LAN.  

•    Facilitate all Internet access.  

•    Support protocols http, https, streaming media i.e. H323, Realmedia.  

•    Provide web-based filtering based on groups.  

•    Utilise white and blacklists to append default security policy.

Northern Grid recommends the use of the Equiinet Cachepilot for caching and filtering services.  The units are highly configurable and easy to use for school technical support staff.   The Cachepilot exceeds all of the BECTA requirements for caching and filtering services.

Files to Download

File	Description	File size
Download PreCaching document	Information about PreCaching & Web Mirroring web page content using a Cachepilot version 5	222 Kb