Transmission Control Protocol Specification
draft-ietf-tcpm-rfc793bis-18
Internet Engineering Task Force W. Eddy, Ed.
Internet-Draft MTI Systems
Obsoletes: 793, 879, 2873, 6093, 6429, August 6, 2020
6528, 6691 (if approved)
Updates: 5961, 1122 (if approved)
Intended status: Standards Track
Expires: February 7, 2021
Transmission Control Protocol Specification
draft-ietf-tcpm-rfc793bis-18
Abstract
This document specifies the Internet's Transmission Control Protocol
(TCP). TCP is an important transport layer protocol in the Internet
stack, and has continuously evolved over decades of use and growth of
the Internet. Over this time, a number of changes have been made to
TCP as it was specified in RFC 793, though these have only been
documented in a piecemeal fashion. This document collects and brings
those changes together with the protocol specification from RFC 793.
This document obsoletes RFC 793, as well as 879, 2873, 6093, 6429,
6528, and 6691 that updated parts of RFC 793. It updates RFC 1122,
and should be considered as a replacement for the portions of that
document dealing with TCP requirements. It updates RFC 5961 due to a
small clarification in reset handling while in the SYN-RECEIVED
state.
RFC EDITOR NOTE: If approved for publication as an RFC, this should
be marked additionally as "STD: 7" and replace RFC 793 in that role.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [4][11] when, and only when, they appear in all capitals, as shown
here.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
Eddy Expires February 7, 2021 [Page 1]
Internet-Draft TCP Specification August 2020
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on February 7, 2021.
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
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material may not have granted the IETF Trust the right to allow
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Without obtaining an adequate license from the person(s) controlling
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it for publication as an RFC or to translate it into languages other
than English.
Table of Contents
1. Purpose and Scope . . . . . . . . . . . . . . . . . . . . . . 3
2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Key TCP Concepts . . . . . . . . . . . . . . . . . . . . 5
3. Functional Specification . . . . . . . . . . . . . . . . . . 6
3.1. Header Format . . . . . . . . . . . . . . . . . . . . . . 6
3.2. Terminology Overview . . . . . . . . . . . . . . . . . . 11
3.2.1. Key Connection State Variables . . . . . . . . . . . 11
3.2.2. State Machine Overview . . . . . . . . . . . . . . . 13
3.3. Sequence Numbers . . . . . . . . . . . . . . . . . . . . 16
3.4. Establishing a connection . . . . . . . . . . . . . . . . 23
3.5. Closing a Connection . . . . . . . . . . . . . . . . . . 29
3.5.1. Half-Closed Connections . . . . . . . . . . . . . . . 32
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