Hierarchical Web caching systems: modeling, design and experimental results

Abstract

Abstract-This paper aims at finding fundamental design principles for hierarchical web caching. An analytical modeling technique is developed to characterize an uncooperative twolevel hierarchical caching system where the least recently used (LRU) algorithm is locally run at each cache. With this modeling technique, we are able to identify a characteristic time for each cache, which plays a fundamental role in understanding the caching processes. In particular, a cache can be viewed roughly as a low-pass filter with its cutoff frequency equal to the inverse of the characteristic time. Documents with access frequencies lower than this cutoff frequency have good chances to pass through the cache without cache hits. This viewpoint enables us to take any branch of the cache tree as a tandem of low-pass filters at different cutoff frequencies, which further results in the finding of two fundamental design principles. Finally, to demonstrate how to use the principles to guide the caching algorithm design, we propose a cooperative hierarchical web caching architecture based on these principles. Both model-based and real trace simulation studies show that the proposed cooperative architecture results in more than 50% memory saving and substantial central processing unit (CPU) power saving for the management and update of cache entries compared with the traditional uncooperative hierarchical caching architecture.Index Terms-Cache replacement algorithms, hierarchical caching, least recently used (LRU), web caching.

Jointly optimal routing and caching for arbitrary network topologies

“…It is of paramount importance in information centric networks (ICNs) [31,57], but also naturally arises in a variety of networking applications such as web-cache design [14,36,58], wireless/femtocell networks [42,45,51], and peer-to-peer networks [16,39], to name a few. Motivated by this problem, we study a caching network, i.e., a network of nodes augmented with additional storage capabilities.…”

“…Intermediate, cache-enabled nodes correspond to storage-augmented routers in the Internet's backbone: such routers forward requests but, departing from traditional network-layer protocols, immediately serve requests for content they store. An extensive body of research, both theoretical [9,14,24,25,30,40,47,48] and experimental [14,31,36,39,49,58], has focused on modeling and analyzing networks of caches in which routing is fixed, and requests follow predetermined paths. For example, shortest paths to the nearest designated server are often used.…”

Estudio, análisis y desarrollo de una red de distribución de contenido y su algoritmo de redirección de usuarios para servicios web y streaming

“…A pesar de demostrarse la mejora del rendimiento en estructuras de cachés de dos niveles [Che_02], también se ha podido comprobar que proxy caché padres de alto nivel pueden sobrecargarse fácilmente si no se emplean técnicas de escalabilidad locales, como las descritas en el capítulo 2.2. Por otro lado, téngase en cuenta que esta solución no optimiza el almacenamiento de contenido, al haber múltiples copias en diferentes niveles de caché.…”

Meta algorithms for hierarchical Web caches

“…Notice that leaving copies everywhere (here after abbreviated LCE), has been considered as a de facto behavior. Despite the vast bibliography on web caching, it wasn't until very recently that a work appeared possing similar questions [1] and, in fact, providing some evidence that LCE can be improved.…”

“…In the following, three new meta algorithms are described and compared against the standard LCE, and the recently proposed one in [1], by means of synthetic and trace-driven simulations. In all cases it is assumed that the Least Recently Used (LRU) replacement algorithm runs in all caches of the hierarchy.…”