TCP Extended Data Offset Option

Document Type Replaced Internet-Draft (individual)
Last updated 2014-07-02
Replaced by draft-ietf-tcpm-tcp-edo
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This Internet-Draft is no longer active.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 that have evolved. This document updates RFC 793 with an optional TCP extension to that space to support the use of multiple large options such as SACK with either TCP Multipath or TCP AO. It also explains why the initial SYN of a connection cannot be extending as 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.)