idnits 2.17.1 draft-ietf-idr-deprecate-as-sets-00.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- No issues found here. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (November 18, 2010) is 4908 days in the past. Is this intentional? Checking references for intended status: Informational ---------------------------------------------------------------------------- No issues found here. Summary: 0 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group W. Kumari 3 Internet-Draft Google, Inc. 4 Intended status: Informational November 18, 2010 5 Expires: May 22, 2011 7 Deprecation of BGP AS_SET, AS_CONFED_SET. 8 draft-ietf-idr-deprecate-as-sets-00.txt 10 Abstract 12 This document deprecates the use of the AS_SET and AS_CONFED_SET 13 types of the AS_PATH in BGPv4. This is done to simplify the design 14 and implementation of the BGP protocol and to make the semantics of 15 the originator of a route more clear. 17 Status of this Memo 19 This Internet-Draft is submitted in full conformance with the 20 provisions of BCP 78 and BCP 79. 22 Internet-Drafts are working documents of the Internet Engineering 23 Task Force (IETF). Note that other groups may also distribute 24 working documents as Internet-Drafts. The list of current Internet- 25 Drafts is at http://datatracker.ietf.org/drafts/current/. 27 Internet-Drafts are draft documents valid for a maximum of six months 28 and may be updated, replaced, or obsoleted by other documents at any 29 time. It is inappropriate to use Internet-Drafts as reference 30 material or to cite them other than as "work in progress." 32 This Internet-Draft will expire on May 22, 2011. 34 Copyright Notice 36 Copyright (c) 2010 IETF Trust and the persons identified as the 37 document authors. All rights reserved. 39 This document is subject to BCP 78 and the IETF Trust's Legal 40 Provisions Relating to IETF Documents 41 (http://trustee.ietf.org/license-info) in effect on the date of 42 publication of this document. Please review these documents 43 carefully, as they describe your rights and restrictions with respect 44 to this document. Code Components extracted from this document must 45 include Simplified BSD License text as described in Section 4.e of 46 the Trust Legal Provisions and are provided without warranty as 47 described in the Simplified BSD License. 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 52 2. Requirements notation . . . . . . . . . . . . . . . . . . . . . 3 53 3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . . 3 54 4. Deployment and modification of behavior . . . . . . . . . . . . 3 55 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 4 56 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 4 57 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 4 58 8. Normative References . . . . . . . . . . . . . . . . . . . . . 4 59 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 4 61 1. Introduction 63 The AS_SET path segment type of the AS_PATH attribute ([RFC4271], 64 Section 4.3) is created by a router that is performing route 65 aggregation and contains an unordered set of ASs that the update has 66 traversed. The AS_CONFED_SET path segment type ([RFC5065]) of the 67 AS_PATH attribute is created by a router that is performing route 68 aggregation and contains an unordered set of Member AS Numbers in the 69 local confederation that the update has traversed (AS_CONFED_SETs are 70 very similar to AS_SETs, but are used within a confederation). 72 By performing aggregation, a router is, in essence, combining 73 multiple routes into a new route. This type of aggregation blurs the 74 semantics of what it means to originate a route. These can cause 75 operational issues that include reachability problems and traffic 76 engineering issues. 78 From analysis of past Internet routing data it is apparent that 79 aggregation that involves AS_SETs is very seldom used in practice on 80 the public network and, when it is, often contains reserved AS 81 numbers ([RFC1930]) and / or only a single AS in the AS_SET. The 82 reductions in table size provided by the aggregation is outweighed by 83 additional complexity in the BGP protocol and confusion regarding 84 what exactly is meant by originating a route. 86 2. Requirements notation 88 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 89 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 90 document are to be interpreted as described in [RFC2119]. 92 3. Terminology 94 Deprecate: To mark (a component of a software standard) as obsolete 95 to warn against its use in the future so that it may be phased 96 out. 98 4. Deployment and modification of behavior 100 It is expected that initially AS_SETs / AS_CONFED_SETs will be 101 deprecated by the few operators that are currently generating them, 102 and operator policy changed to filter them. Operators should take 103 note that new technologies (such as those that make use of the RPKI) 104 MAY not support routes with AS_SETs / AS_CONFED_SETs in them, and MAY 105 treat as infeasible routes containing them. 107 5. IANA Considerations 109 This document contains no IANA considerations. 111 6. Security Considerations 113 By removing support for the AS_SET path segment type of the AS_PATH 114 attribute future BGP implementations can be simplified.. This will 115 also simplify the design and implementation of the RPKI and systems 116 that will rely on it. By removing corner cases we remove complexity 117 and code that is not exercised very often, which decreases the attack 118 surface. 120 7. Acknowledgements 122 The author would like to thank Tony Li, Randy Bush, John Scudder, 123 Chris Morrow, Danny McPherson, Douglas Montgomery, Enke Chen, Florian 124 Weimer, Ilya Varlashkin, Jakob Heitz, John Leslie, Keyur Patel, Paul 125 Jakma, Rob Austein, Russ Housley, Sandra Murphy, Sriram Kotikalapudi, 126 Steve Bellovin, Steve Kent, Steve Padgett, Alfred Hones, Tom Petch, 127 everyone in IDR and everyone else who provided input. 129 Apologies to those who I may have missed, it was not intentional. 131 8. Normative References 133 [RFC1930] Hawkinson, J. and T. Bates, "Guidelines for creation, 134 selection, and registration of an Autonomous System (AS)", 135 BCP 6, RFC 1930, March 1996. 137 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 138 Requirement Levels", BCP 14, RFC 2119, March 1997. 140 [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway 141 Protocol 4 (BGP-4)", RFC 4271, January 2006. 143 [RFC5065] Traina, P., McPherson, D., and J. Scudder, "Autonomous 144 System Confederations for BGP", RFC 5065, August 2007. 146 Author's Address 148 Warren Kumari 149 Google, Inc. 150 1600 Amphitheatre Parkway 151 Mountain View, CA 94043 152 US 154 Phone: +1 571 748 4373 155 Email: warren@kumari.net