FastReplica: Efficient Large File Distribution
within Content Delivery Networks

Ludmila Cherkasova
Hewlett-Packard Laboratories
1501 Page Mill Road, Palo Alto, CA 94303
cherkasova@hpl.hp.com

Jangwon Lee
University of Texas at Austin
Austin, Texas 78712
jangwlee@ece.utexas.edu

Abstract. In this work, we consider a large-scale distributed network of servers and a problem of content distribution across it. We propose a novel algorithm, called FastReplica, for an efficient and reliable replication of large files in the Internet environment. There are a few basic ideas exploited in FastReplica. In order to replicate a large file among $n$ nodes ($n$ is in the range of 10-30 nodes), the original file is partitioned into $n$ subfiles of equal size and each subfile is transferred to a different node in the group. After that, each node propagates its subfile to the remaining nodes in the group. Thus instead of the typical replication of an entire file to $n$ nodes by using $n$ Internet paths, connecting the original node to the replication group, FastReplica exploits $n \times n$ Internet paths within the replication group where each path is used for transferring $1\over n$-th of the file. We design a scalable and reliable FastReplica algorithm which can be used for replication of large files to a large group of nodes. The new method is simple and inexpensive. It does not require any changes or modifications to the existing Internet infrastructure, and at the same time, it significantly reduces the file replication time as we demonstrate through experiments on a prototype implementation of FastReplica in a wide-area testbed.