by Stuart Hardy, Business Unit Manager of EOH’s Carrier and Network Solutions Division

What is content caching?

Caching refers to a method of duplicating international content at a local level. Large volumes of content are constantly created and placed on servers for user consumption, and access to this content needs to be optimised.

As a simplified example, let’s take an HD video that has been created. Initially this video is placed on a server owned by the content creator, which is located in a specific geographical place. Anyone wishing to watch the video therefore needs to connect to this particular server. The connection route would typically be to one’s local ISP, then through a series of server hops until reaching the server onto which the video has been loaded.

Obviously this takes a certain amount of time and bandwidth. The actual time and bandwidth amounts may be relatively small for a single short video, but they can increase significantly as the size or volume of content increases.

What caching does is create a duplicate of the content on a local server, geographically closer to the user’s ISP. For instance, if the content was originally placed on a server located in Canada, a cache is created in South African so that South African users don’t need to make all the server hops to reach the content, because it is closer.

Why is content caching more effective?

Historically the primary benefit of caching was a reduction of bandwidth cost. Bandwidth used to be pretty expensive, compared to the situation today. It was therefore important to minimise the amount of bandwidth – particularly international bandwidth – used to access content on the Internet.

Today caching is more about speed of delivery of content. This is especially true when dealing with large volumes of content, like video or live streaming media. By caching the content locally, access speed and download times improve: the user gets the content quicker.

Content distribution networks (CDN)

Content delivery networks are essentially caching platforms where content creators and publishers pay CDN providers to have their content and other services made available closer to their end users, on a global basis. The CDN providers then pay local ISPs and data centre operators to house the content. The result is multiple data centres across the world creating a distributed network of servers on which the content is duplicated for local access.

There are several CDNs in South Africa, which helps to significantly reduce the bandwidth and speed overhead on international networks. These providers include Google, Level 3, CloudFlare and Akamai.


Stuart Hardy has been in the ICT industry since 1997, has been in the Telecommunications industry since 1997, intimately involved in product development, operations and product marketing roles. He has held Executive level positions in some of the largest Operators in South Africa and has founded and driven two successful start-up companies in the Mobile data and Wireless networking spaces. Today, Stuart is a Divisional Director for EOH in their Telecommunications sector.