Resource Pooling in Large-Scale Content Delivery Systems

TL;DR

This paper analyzes how resource pooling among caches in large-scale content delivery networks impacts performance, depending on content popularity distribution, and provides insights for system optimization.

Contribution

It investigates the performance benefits of resource pooling in content delivery systems based on content popularity profiles, guiding system design choices.

Findings

Resource pooling improves performance when content popularity is uniform.

Benefits of resource pooling are negligible with highly skewed content popularity.

Performance gains depend on cache storage capacity and content replication strategies.

Abstract

Content delivery networks are a key infrastructure component used by Video on Demand (VoD) services to deliver content over the Internet. We study a content delivery system consisting of a central server and multiple co-located caches, each with limited storage and service capabilities. This work evaluates the performance of such a system as a function of the storage capacity of the caches, the content replication strategy, and the service policy. This analysis can be used for a system-level optimization of these design choices. The focus of this work is on understanding the benefits of allowing caches to pool their resources to serve user requests. We show that the benefits of resource pooling depend on the popularity profile of the contents offered by the VoD service. More specifically, if the popularity does not vary drastically across contents, resource pooling can lead to significant improvements in the system performance. In contrast, if the content popularity is uneven, the benefits of resource pooling are negligible.