Web caching on smartphones

Abstract

Web caching in mobile networks is critical due to the unprecedented cellular traffic growth that far exceeds the deployment of cellular infrastructures. Caching on handsets is particularly important as it eliminates all network-related overheads. We perform the first network-wide study of the redundant transfers caused by inefficient web caching on handsets, using a dataset collected from 3 million smartphone users of a large commercial cellular carrier, as well as another five-month-long trace contributed by 20 smartphone users. Our findings suggest that redundant transfers contribute 18% and 20% of the total HTTP traffic volume in the two datasets. Also they are responsible for 17% of the bytes, 7% of the radio energy consumption, 6% of the signaling load, and 9% of the radio resource utilization of all cellular data traffic in the second dataset. Most of such redundant transfers are caused by the smartphone web caching implementation that does not fully support or strictly follow the protocol specification, or by developers not fully utilizing the caching support provided by the libraries. This is further confirmed by our caching tests of 10 popular HTTP libraries and mobile browsers. Improving the cache implementation will bring considerable reduction of network traffic volume, cellular resource consumption, handset energy consumption, and user-perceived latency, benefiting both cellular carriers and customers.

How to Reduce Smartphone Traffic Volume by 30%?

“…The cache size is assumed to be 256 MB. As long as the cache size is not too small (e.g., >50 MB), it has little impact on the RE effectiveness, as shown in [17].…”

“…They were given 11 Motorola Atrix and 9 Samsung Galaxy S smartphones, all running Android 2.2, with unlimited voice, text and data plans from a large 3G carrier in the U.S. This dataset was also used in our earlier study of smartphone HTTP caching [17] 1 . We deployed custom data collection software on the 20 handsets.…”

“…In [17], we found for web caching, there exists a huge gap between the protocol specification and the implementation on today's mobile devices. A 17% reduction in the overall traffic volume can be achieved if the HTTP caching protocol is fully supported and strictly followed by smartphone apps and mobile browsers.…”

“…In our recent work [17], we investigated HTTP caching on smartphones. We found that for web caching, there exists a huge gap between the protocol specification and the implementation on today's mobile devices.…”

A cooperation-driven ICN-based caching scheme for mobile content chunk delivery at RAN

“…In mobile cellular networks, due to the fast growth of cellular traffic that cannot be coped well with the evolvement of cellular infrastructures, there have been many research works on Web caching at backhaul links [8], [9] or at mobile devices [10], [11]. Caching at RAN have been exploited in [12] [22] that mainly focus on independent caching.…”