TCP SYN Extended Option Space Using an Out-of-Band Segment

Document Type Expired Internet-Draft (individual)
Authors Joseph Touch  , Ted Faber 
Last updated 2019-01-20 (latest revision 2018-07-19)
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This Internet-Draft is no longer active. A copy of the expired Internet-Draft can be found at


This document describes an experimental method to extend the option space for connection parameters within the initial TCP SYN segment, at the start of a TCP connection. This method effectively extends the option space of an initial SYN by using an additional coupled segment that is sent 'out-of-band'. It complements the proposed Extended Data Offset (EDO) option that is applicable only after the initial segment.


Joseph Touch (
Ted Faber (

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