ECN (RFC 3168), 1/2 New for Windows Vista Straightforward to implement We ran into a number of problems: IGD problem #1: one of the most popular versions from one of the most popular vendors When a data packet arrives with either ECT(0) or ECT(1) (indicating successful ECN capability negotiation) indicated, router crashed Cannot be recovered at TCP layer IGD problem #2: multiple popular vendors with popular models When the 3-way handshake completes, prior to any data being sent, router hit a bug causing further packet loss Easily detected and recovered at TCP layer |