Advancing ACK Handling for Wireless Transports
draft-li-tcpm-advancing-ack-for-wireless-00

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TCP Maintenance and Minor Extensions                               T. Li
Internet-Draft                                                  K. Zheng
Intended status: Experimental                                  R. Jadhav
Expires: September 7, 2020                                       J. Kang
                                                     Huawei Technologies
                                                           March 6, 2020

             Advancing ACK Handling for Wireless Transports
              draft-li-tcpm-advancing-ack-for-wireless-00

Abstract

   Acknowledgement (ACK) is a basic function and implemented in most of
   the ordered and reliable transport protocols [RFC0793].  Legacy TCP
   ACK is designed with high frequency to guarantee correct interaction
   between sender and receiver.  However, the shared nature of the
   wireless medium over wireless local area network (WLAN) induces
   contention between data transport and backward signaling, such as
   acknowledgement.  The current way of TCP acknowledgment induces
   control overhead which is counter-productive for TCP performance
   especially for WLAN scenarios.

   This document conducts the ACK frequency breakdown, analyzes several
   ways of reducing ACK frequency, and discusses the compatibility
   issues with existing systems in detail.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
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   This Internet-Draft will expire on September 7, 2020.

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Copyright Notice

   Copyright (c) 2020 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (https://trustee.ietf.org/license-info) in effect on the date of
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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Requirements Language . . . . . . . . . . . . . . . . . . . .   2
   2.  Problem Statement . . . . . . . . . . . . . . . . . . . . . .   2
   3.  ACK Frequency Minimization on the Transport Layer . . . . . .   4
     3.1.  Ways to reduce ACK frequency  . . . . . . . . . . . . . .   4
     3.2.  Provisioning for TACK . . . . . . . . . . . . . . . . . .   5
     3.3.  Benefits for applying TACK  . . . . . . . . . . . . . . .   6
   4.  Difference between delayed ACK and TACK . . . . . . . . . . .   6
   5.  Compatibility issues  . . . . . . . . . . . . . . . . . . . .   7
     5.1.  Issues in loss recovery . . . . . . . . . . . . . . . . .   7
     5.2.  Issues in round-trip timing . . . . . . . . . . . . . . .   8
     5.3.  Issues in send pattern  . . . . . . . . . . . . . . . . .   8
     5.4.  Issues in startup cwnd update . . . . . . . . . . . . . .   8
     5.5.  Issues in awnd update . . . . . . . . . . . . . . . . . .   8
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   9
   7.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   9
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   9
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   9
     8.2.  Informative References  . . . . . . . . . . . . . . . . .  10
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  11

1.  Requirements Language

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
   document are to be interpreted as described in RFC 2119 [RFC2119].

2.  Problem Statement

   It is well-studied that medium acquisition overhead in WLAN based on
   the IEEE 802.11 medium access control (MAC) protocol [WL] can
   severely hamper TCP throughput, and TCP's many small ACKs are one

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   reason [Eugenio][Lynne].  Basically, TCP sends an ACK for every one
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