Tony Li

A GRE tunnel gives a packet a second address without taking away the first. The outer header decides how the envelope crosses an underlay; the inner header still decides what happens after the envelope is opened. Between them, the smallest GRE header can occupy only four octets. That economy is the point—and the trap. Tony Li's documented co-authorship of the original and Standards Track GRE specifications shows how a thin common mechanism can connect unlike networks without becoming their governor. It also shows why every omitted decision returns as work for the endpoints.

Across a person-attributed IETF record spanning CIDR, address policy, BGP, IS-IS authentication, and modern flooding controls, Tony Li's work shows that Internet scale depends on records whose authority ends where topology, local policy, receiver capacity, and running code begin.