Dr. Rekhter was one of the leading architects and a major software developer of the NSFNET Backbone Phase II.
In January 1989 at the 12th IETF meeting in Austin, Texas, Yakov Rekhter and Kirk Lougheed sat down at a table to design what ultimately became the Border Gateway Protocol (BGP).
The initial BGP design was recorded on a napkin rumored to have been heavily spattered with ketchup.
The design on the napkin was expanded to three hand-written sheets of paper from which the first interoperable BGP implementation was quickly developed.
A photocopy of these 3 sheets of paper now hangs on the wall of a routing protocol development area at Cisco Systems in Milpitas, California.