Dynamic Cache Partitioning for Encrypted Content Delivery
28th International Teletraffic Congress (ITC 28), Würzburg, Germany, (September 2016)Abstract
In-network caching is an appealing solution to cope with the increasing
bandwidth demand of video, audio and data transfer over the Internet.
Nonetheless, an increasing share of content delivery services adopt
encryption through HTTPS, which is not compatible with traditional
ISP-managed approaches like transparent and proxy caching. This raises the
need for solutions involving both Internet Service Providers (ISP) and
Content Providers (CP): by design, the solution should preserve
business-critical CP information (e.g., content popularity, user
preferences) on the one hand, while allowing for a deeper integration of
caches in the ISP architecture (e.g., in 5G femto-cells) on the other hand.
In this paper we address this issue by considering a content-oblivious
ISP-operated cache. The ISP allocates the cache storage to various content
providers so as to maximize the bandwidth savings provided by the cache:
the main novelty lies in the fact that, to protect business-critical
information, ISPs only need to measure the aggregated miss rates of the
individual CPs. We propose a cache allocation algorithm based on a
perturbed stochastic subgradient method, and prove that the algorithm
converges to the allocation that maximizes the overall cache hit rate. We
use extensive simulations to validate the algorithm and to assess its
convergence rate under stationary and non-stationary content popularities.
Our results (i) testify the feasibility of content-oblivious caches and
(ii) show that the proposed algorithm can achieve within 15% from the
global optimum in our evaluation.