Internet - Draft ECN Tunnelling Oct 2008

Layered Encapsulation of Congestion Notification draft-ietf-tsvwg-ecn-tunnel-01 Status of this Memo By submitting this Internet-Draft, each author represents that any applicable patent or other IPR claims of which he or she is aware have been or will be disclosed, and any of which he or she becomes aware will be disclosed, in accordance with Section 6 of BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." Abstract This document redefines how the explicit congestion notification (ECN) field of the outer IP header of a tunnel should be constructed. It brings all IP in IP tunnels (v4 or v6) into line with the way IPsec tunnels now construct the ECN field. It includes a thorough analysis of the reasoning for this change and the implications. It also gives guidelines on the encapsulation of IP congestion notification by any outer header, whether encapsulated in an IP tunnel or in a lower layer header. Following these guidelines should help interworking, if the IETF or other standards bodies specify any new encapsulation of congestion notification.