Redundancy Elimination on Unidirectional Lossy Links

Abstract

Redundant data transmission, which is very common in computer networks, degrades bandwidth efficiency and wastes energy. To reduce such redundancy, many redundancy elimination (RE) techniques have been proposed. Most of them require strict history synchronization between the sender and receiver, and therefore assume the existence of bidirectional links to maintain the synchronization. This paper presents MinMax, a new RE mechanism that is specially designed for unidirectional lossy links. Using an existing fingerprinting algorithm, MinMax eliminates a region of payload in an outgoing packet only when the region is common in a certain number of previous packets. Thus over a lossy link, MinMax significantly reduces decompression failures at the receiver without resorting to any forms of feedback and retransmission. Experiments on synthetic data and real-world traffic show that MinMax is able to maintain fair bandwidth savings while inducing negligible decompression failures even when the packet loss rate of the link is as high as 20%.