An Analysis of Web Caching in Current Mobile Broadband Scenarios

The web caching business has significantly changed over the recent years. The percentage of content that is suitable for caching has constantly decreased, e.g. due to unfavorable content formats like Flash or varying URLs due to usage of CDNs. While this of course has a negative impact on the effectiveness of caching, also other parts of the equation have changed: Transmission cost has dropped significantly, and so has the cost to run a cache, especially in times where Cloud Computing approaches commoditize such operations. At the same time, the topic of caching as such remains highly relevant, as the data volumes in the networks continue to grow exponentially and net work operators are seeking ways to cope with this demand in an efficient manner. We have therefore analyzed a realistic mobile network topology consisting of primary and secondary telecommunication sites that can be found in many deployments, and have determined the efficiency of web caching, taking into account the latest changes in the ecosystem. An abstract telecommunication site model has been developed and parameterized with a realistic traffic and cost structure for a Western European operator. We find that, contrary to other research that suggests the days of caching are over, there is a clear business case for introducing web caches in primary sites. With current hosting costs and economies of scale, a caching system can already be efficient if only 5.1% of the traffic is suitable for caching. For the secondary sites the same effect can be observed and, although the effect is not that distinct, also here web caching can bring clear benefits in certain scenarios.