TCP Extended Data Offset Option

Document Type Expired Internet-Draft (tcpm WG)
Authors Joseph Touch  , Wesley Eddy 
Last updated 2019-01-20 (latest revision 2018-07-19)
Replaces draft-touch-tcpm-tcp-edo
Stream Internet Engineering Task Force (IETF)
Intended RFC status Proposed Standard
Expired & archived
pdf htmlized (tools) htmlized bibtex
Stream WG state WG Document (wg milestone: Nov 2022 - Submit document on a... )
Document shepherd No shepherd assigned
IESG IESG state Expired
Consensus Boilerplate Unknown
Telechat date
Responsible AD (None)
Send notices to (None)

This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


TCP segments include a Data Offset field to indicate space for TCP options but the size of the field can limit the space available for complex options such as SACK and Multipath TCP and can limit the combination of such options supported in a single connection. This document updates RFC 793 with an optional TCP extension to that space to support the use of multiple large options. It also explains why the initial SYN of a connection cannot be extending a single segment.


Joseph Touch (
Wesley Eddy (

(Note: The e-mail addresses provided for the authors of this Internet-Draft may no longer be valid.)