Browse Prior Art Database

TCP Performance Implications of Network Path Asymmetry (RFC3449)

IP.com Disclosure Number: IPCOM000010583D
Original Publication Date: 2002-Dec-01
Included in the Prior Art Database: 2002-Dec-19

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

H. Balakrishnan: AUTHOR [+4]

Abstract

This document describes TCP performance problems that arise because of asymmetric effects. These problems arise in several access networks, including bandwidth-asymmetric networks and packet radio subnetworks, for different underlying reasons. However, the end result on TCP performance is the same in both cases: performance often degrades significantly because of imperfection and variability in the ACK feedback from the receiver to the sender.

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Network Working Group� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � H. Balakrishnan

Request for Comments: 3449� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � MIT LCS

BCP: 69� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � V. N. Padmanabhan

Category: Best Current Practice� � � � � � � � � � � � � � � � � � � � � � Microsoft Research

� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � G. Fairhurst

� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � M. Sooriyabandara

� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � University of Aberdeen, U.K.

� � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � � December 2002

� � � � � � � � � � � � � � � � � � � � TCP Performance Implications

� � � � � � � � � � � � � � � � � � � � � � of Network Path Asymmetry

Status of this Memo

� � This document specifies an Internet Best Current Practices for the

� � Internet Community, and requests discussion and suggestions for

� � improvements.� Distribution of this memo is unlimited.

Copyright Notice

� � Copyright (C) The Internet Society (2002).� All Rights Reserved.

Abstract

� � This document describes TCP performance problems that arise because

� � of asymmetric effects.� These problems arise in several access

� � networks, including bandwidth-asymmetric networks and packet radio

� � subnetworks, for different underlying reasons.� However, the end

� � result on TCP performance is the same in both cases: performance

� � often degrades significantly because of imperfection and variability

� � in the ACK feedback from the receiver to the sender.

� � The document details several mitigations to these effects, which have

� � either been proposed or evaluated in the literature, or are currently

� � deployed in networks.� These solutions use a combination of local

� � link-layer techniques, subnetwork, and end-to-end mechanisms,

� � consisting of: (i) techniques to manage the channel used for the

� � upstream bottleneck link carrying the ACKs, typically using header

� � compression or reducing the frequency of TCP ACKs, (ii) techniques to

� � handle this reduced ACK frequency to retain the TCP sender's

� � acknowledgment-triggered self-clocking and (iii) techniques to

� � schedule the data and ACK packets in the reverse direction to improve

� � performance in the presence of two-way traffic.� Each technique is

� � described, together with known issues, and recommendations for use.

� � A summary of the recommendations is provided at the end of the

� � document.

Balakrishnan et. al.� � � � Best Current Practice� � � � � � � � � � � � � � � � � [Page 1]

RFC 3449� � � � � � � � � � � � � � � PILC - Asymmetric Links� � � � � � � � � � � December 2002

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