Ask HN: Protocol Negotiation in Intergalactic Computer Network?

A while back, I remember reading how back when they were working on the Intergalactic Network under Licklider, etc., one of the problems they tackled was how to have two computers negotiate a common protocol to communicate with each other. The problem, if I remember correctly, was framed as a first contact scenario of two alien civilizations.

I have now forgotten where I read this and can't find any resource on whether they made any progress in this field. Any one has any idea what I am talking about here? Are there any publically available records of how much progress they made, which parts of the problem they were able to solve and what were those solutions?