Checksum-based loss differentiation

Abstract

In a wireless environment the common transport protocol assumption that all packet losses are due to congestion no longer holds true. If the transport protocols react identically to both congestion and non-congestion related losses, performance will degrade. To avoid this performance problem, transport protocols must be able to differentiate between losses that are due to congestion and losses that are due to wireless link errors. Suitable congestion avoidance behavior can then be applied as appropriate. This paper overviews previous work on loss differentiation, and proposes a checksum-based scheme. The proposed scheme reuses the checksums already available at various layers in the receiver end-host protocol stack. It is an end-to-end solution for the case where the lossy link is the last hop. Header decoding, data integrity and other issues related to the implementation of our checksum-based scheme are also discussed.