--- 1/draft-ietf-mpls-explicit-null-00.txt 2006-02-05 00:38:29.000000000 +0100 +++ 2/draft-ietf-mpls-explicit-null-01.txt 2006-02-05 00:38:29.000000000 +0100 @@ -1,21 +1,21 @@ Network Working Group Eric C. Rosen Internet Draft Cisco Systems, Inc. -Expiration Date: September 2004 +Expiration Date: October 2004 Updates RFC 3032 - March 2004 + April 2004 Removing a Restriction on the use of MPLS Explicit NULL - draft-ietf-mpls-explicit-null-00.txt + draft-ietf-mpls-explicit-null-01.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. 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. @@ -37,26 +37,27 @@ reserved label value known as "IPv6 Explicit NULL". Previously, these labels were only legal when they occurred at the bottom of the MPLS label stack. This restriction is now removed, so that these label values may legally occur anywhere in the stack. Contents 1 Introduction ......................................... 2 2 Detail of Change ..................................... 2 3 Reasons for Change ................................... 4 - 4 Acknowledgments ...................................... 5 - 5 Normative References ................................. 5 - 6 Informative References ............................... 5 - 7 Author's Address ..................................... 6 - 8 Intellectual Property Notice ......................... 6 - 9 Copyright Notice ..................................... 6 + 4 Security Considerations .............................. 5 + 5 Acknowledgments ...................................... 5 + 6 Normative References ................................. 6 + 7 Informative References ............................... 6 + 8 Author's Address ..................................... 6 + 9 Intellectual Property Notice ......................... 6 + 10 Copyright Notice ..................................... 7 1. Introduction RFC 3032 defines a reserved label value known as "IPv4 Explicit NULL" and a reserved label value known as "IPv6 Explicit NULL". It states that these label values are only legal at the bottom of the MPLS label stack. However, no reason is given for this restriction. It has turned out that in practice there are some situations in which it is useful to send MPLS packets which have Explicit NULL occur @@ -188,43 +189,49 @@ using Explicit NULL enables the egress to determine immediately (i.e., without need for lookup in the Label Information Base) that the further forwarding of the packet is to be determined by whatever is below the label. Avoiding this lookup can have favorable implications on forwarding performance. Removing the restriction that Explicit Null only occur at the bottom of the stack is the simplest way to facilitate the proper operation of the Pipe Model. -4. Acknowledgments +4. Security Considerations + + This document updates RFC 3032 by allowing Explicit NULL to occur at + any position in the label stack. This modification does not impose + any new security considerations beyond those discussed in RFC 3032. + +5. Acknowledgments Thanks to Rahul Aggarwal, Francois LeFaucheur, Yakov Rekhter, and Dan Tappan for their helpful comments. -5. Normative References +6. Normative References [RFC3032] "MPLS Label Stack Encoding", Rosen, et. al., January 2001 -6. Informative References +7. Informative References [RFC3270] "Multi-Protocol Label Switching (MPLS) Support of Differentiated Services", Le Faucheur, et. al., May 2002 -7. Author's Address +8. Author's Address Eric C. Rosen Cisco Systems, Inc. 1414 Massachusetts Avenue Boxborough, MA 01719 Email: erosen@cisco.com -8. Intellectual Property Notice +9. Intellectual Property Notice The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in this document or the extent to which any license under such rights might or might not be available; neither does it represent that it has made any effort to identify any such rights. Information on the IETF's procedures with respect to rights in standards-track and standards-related documentation can be found in BCP-11. Copies of claims of rights made available for publication and any assurances of @@ -232,21 +239,21 @@ obtain a general license or permission for the use of such proprietary rights by implementors or users of this specification can be obtained from the IETF Secretariat. The IETF invites any interested party to bring to its attention any copyrights, patents or patent applications, or other proprietary rights which may cover technology that may be required to practice this standard. Please address the information to the IETF Executive Director. -9. Copyright Notice +10. Copyright Notice "Copyright (C) The Internet Society (2004). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing