TCP SYN Extended Option Space Using an Out-of-Band Segment
Ted Faber, Joseph D. Touch · 2018
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.