Change RFC 3540 "Robust Explicit Congestion Notification (ECN) Signaling with Nonces" to Historic
status-change-ecn-signaling-with-nonces-to-historic-01

   RFC 3540 described an optional usage of the ECT(0) and ECT(1) bits 
   in the IP header to verify the correct behavior of an ECN receiver and 
   verify that that there is no other interference that conceals marked
   (or dropped) packets in the signaling path, for use in experimentation.

   While the ECN Nonce works as specified, and has been deployed in
   limited environments, widespread usage in the Internet has not
   materialized. 

   With the emergence of new experimental functionality that depends on
   use of the ECT(1) codepoint for other purposes, continuing to reserve
   that codepoint for the ECN Nonce experiment is no longer justified.
   The TSVWG working group has requested that this experiment be
   explicitly concluded, and RFC 5340 moved to Historic status. 

   Further explanation is available in draft-ietf-tsvwg-ecn-experimentation,
   Section 3.