Transmission Control Protocol (TCP) Specification
draft-ietf-tcpm-rfc793bis-20
Internet Engineering Task Force W. Eddy, Ed.
Internet-Draft MTI Systems
Obsoletes: 793, 879, 2873, 6093, 6429, January 21, 2021
6528, 6691 (if approved)
Updates: 5961, 1122 (if approved)
Intended status: Standards Track
Expires: July 25, 2021
Transmission Control Protocol (TCP) Specification
draft-ietf-tcpm-rfc793bis-20
Abstract
This document specifies the Transmission Control Protocol (TCP). TCP
is an important transport layer protocol in the Internet protocol
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 RFCs 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 also updates RFC
5961 by adding a small clarification in reset handling while in the
SYN-RECEIVED state. The TCP header control bits from RFC 793 have
also been updated based on RFC 3168.
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.
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/.
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 July 25, 2021.
Eddy Expires July 25, 2021 [Page 1]
Internet-Draft TCP Specification January 2021
Copyright Notice
Copyright (c) 2021 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
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
This document may contain material from IETF Documents or IETF
Contributions published or made publicly available before November
10, 2008. The person(s) controlling the copyright in some of this
material may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards Process.
Without obtaining an adequate license from the person(s) controlling
the copyright in such materials, this document may not be modified
outside the IETF Standards Process, and derivative works of it may
not be created outside the IETF Standards Process, except to format
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. Requirements Language . . . . . . . . . . . . . . . . . . 5
2.2. Key TCP Concepts . . . . . . . . . . . . . . . . . . . . 5
3. Functional Specification . . . . . . . . . . . . . . . . . . 6
3.1. Header Format . . . . . . . . . . . . . . . . . . . . . . 6
3.2. TCP Terminology Overview . . . . . . . . . . . . . . . . 12
3.2.1. Key Connection State Variables . . . . . . . . . . . 12
3.2.2. State Machine Overview . . . . . . . . . . . . . . . 14
3.3. Sequence Numbers . . . . . . . . . . . . . . . . . . . . 17
3.4. Establishing a connection . . . . . . . . . . . . . . . . 24
3.5. Closing a Connection . . . . . . . . . . . . . . . . . . 31
3.5.1. Half-Closed Connections . . . . . . . . . . . . . . . 33
3.6. Segmentation . . . . . . . . . . . . . . . . . . . . . . 34
3.6.1. Maximum Segment Size Option . . . . . . . . . . . . . 35
3.6.2. Path MTU Discovery . . . . . . . . . . . . . . . . . 37
Show full document text