Design, implementation, and evaluation of differentiated caching services

With the dramatic explosion of online information, the Internet is undergoing a transition from a data communication infrastructure to a global information utility. PDAs, wireless phones, web-enabled vehicles, modem PCs and high-end workstations can be viewed as appliances that “plug-in ” to this utility for information. The increasing diversity of such appliances calls for an archi-tecture for performance differentiation of information access. The key performance accelerator on the Internet is the caching and content distribution infrastructure. While many research efforts addressed performance differentiation in the network and on web servers, providing multiple levels of service in the caching system has received much less attention. This paper has two main contributions. First, we describe, implement, and evaluate an archi-tecture for differentiated content caching services as a key element of the Internet content distri-bution architecture. Second, we describe a control-theoretical approach that lays well-understood theoretical foundations for resource management to achieve performance differentiation in proxy caches. An experimental study using the Squid proxy cache shows that differentiated caching ser-vices provide significantly better performance to the premium content classes