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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: 'RFC5226' is defined on line 184, but no explicit reference was found in the text == Outdated reference: A later version (-10) exists of draft-ietf-idr-as4octet-extcomm-generic-subtype-03 ** Obsolete normative reference: RFC 5226 (Obsoleted by RFC 8126) Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group B. Decraene 3 Internet-Draft France Telecom - Orange 4 Intended status: Standards Track P. Francois 5 Expires: November 24, 2011 Universite catholique de Louvain 6 May 23, 2011 8 Assigned BGP extended communities 9 draft-ietf-idr-reserved-extended-communities-01 11 Abstract 13 This document defines two IANA registries in order to assign 14 transitive and non-transitive extended communities from. These are 15 similar to the existing well-known BGP communities defined in RFC 16 1997 but provide an easier control of inter-AS community 17 advertisement as a community could be chosen as transitive or non- 18 transitive across ASes. 20 For that purpose, this document defines the use of the reserved AS 21 number 0 for the transitive and non-transitive generic four-octet AS 22 specific extended community types. 24 Requirements Language 26 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 27 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 28 document are to be interpreted as described in RFC 2119 [RFC2119]. 30 Status of this Memo 32 This Internet-Draft is submitted in full conformance with the 33 provisions of BCP 78 and BCP 79. 35 Internet-Drafts are working documents of the Internet Engineering 36 Task Force (IETF). Note that other groups may also distribute 37 working documents as Internet-Drafts. The list of current Internet- 38 Drafts is at http://datatracker.ietf.org/drafts/current/. 40 Internet-Drafts are draft documents valid for a maximum of six months 41 and may be updated, replaced, or obsoleted by other documents at any 42 time. It is inappropriate to use Internet-Drafts as reference 43 material or to cite them other than as "work in progress." 45 This Internet-Draft will expire on November 24, 2011. 47 Copyright Notice 48 Copyright (c) 2011 IETF Trust and the persons identified as the 49 document authors. All rights reserved. 51 This document is subject to BCP 78 and the IETF Trust's Legal 52 Provisions Relating to IETF Documents 53 (http://trustee.ietf.org/license-info) in effect on the date of 54 publication of this document. Please review these documents 55 carefully, as they describe your rights and restrictions with respect 56 to this document. Code Components extracted from this document must 57 include Simplified BSD License text as described in Section 4.e of 58 the Trust Legal Provisions and are provided without warranty as 59 described in the Simplified BSD License. 61 1. Introduction 63 [RFC1997] defines the BGP community attribute and some BGP well-known 64 communities whose meaning SHALL be understood by all compliant 65 implementations. New communities can be registered in the IANA "BGP 66 Well-known Communities" registry but it can't be assumed anymore that 67 they will be known by all BGP implementations. Implementations or 68 BGP policies which recognize them will behave as specified. 69 Implementations which do not recognize those new reserved communities 70 will propagate them from BGP neighbor to BGP neighbor and from AS to 71 AS with an unlimited scope. 73 There is currently no agreed way to register a non transitive well- 74 known community: 76 On one hand, [RFC1997] defines BGP Well-known communities with no 77 structure to set their transitiveness across ASes. Without 78 structure, communities can only be filtered by explicitly enumerating 79 all community values that will be denied or allowed to BGP speakers 80 in neighboring ASes. This is not satisfactory as this would require 81 upgrading all border routers to understand this community before its 82 first usage. 84 On the other hand, [RFC4360] defines the BGP extended community 85 attribute with a structure including a type and a transitive bit "T". 86 This transitive bit, when set, allows to restrict the scope of the 87 community within an AS. But their is no IANA registry to allocate 88 one well-known extended community. [RFC4360] defines IANA registries 89 to allocate BGP Extended Communities types. Each type is able to 90 encode 2^48 or 2^56 values depending on the type being extended or 91 regular. Therefore, one needing to reserve a single non-transitive 92 extended community would need to reserve an extended subtype which 93 represents 2^48 communities, while a single value is used. This 94 would both waste the resources and disable the ability to define 95 global policies on reserved communities, such as to accept them or to 96 filter them out. 98 To address this limitation, this document defines two IANA registries 99 in order to allow the registration of transitive and non-transitive 100 extended communities. These are similar to the existing Well-known 101 BGP communities defined in [RFC1997] but provides a control on 102 inter-AS community advertisement as a community could be chosen as 103 transitive or non-transitive across ASes. 105 2. Assigned extended communities 107 [I-D.ietf-idr-as4octet-extcomm-generic-subtype] defines a generic 108 sub-type for the four-octet AS specific extended community. The 109 value of the four-octets Global Administrator sub-field contains a 110 four-octet Autonomous System number. The value of their two-octet 111 Local Administrator sub-field has semantics defined by the Autonomous 112 System set in the Global Administrator sub-field. 114 This document updates [I-D.ietf-idr-as4octet-extcomm-generic-subtype] 115 and defines the use of the Local Administrator sub-field when the AS 116 number encoded in the Global Administrator sub-field has the reserved 117 value 0. 119 When the AS number encoded in the Global Administrator sub-field has 120 the reserved value 0, the communities have global significance. The 121 lists of those communities are maintained by the IANA in the 122 registries "Assigned transitive extended communities" for the 123 "transitive generic four-octet AS specific" extended community type 124 and "Assigned non-transitive extended communities" for the "non- 125 transitive generic four-octet AS specific" extended community type. 127 Note that this use of the reserved AS number 0 in the AS field of the 128 communities is similar to the one defined by [RFC1997] for the BGP 129 Well-Known communities. 131 3. IANA Considerations 133 The IANA is requested to create and maintain a registry entitled 134 "Assigned transitive extended communities" with the following 135 registration procedure: 137 Registry Name: Assigned transitive extended communities 139 Range Registration Procedures 140 ----------- ------------------------- 141 0x0000-8000 First Come First Served 142 0x8001-FFFF Standards Action/Early IANA Allocation 144 The IANA is requested to create and maintain a registry entitled 145 "Assigned non-transitive extended communities" with the following 146 registration procedure: 148 Registry Name: Assigned non-transitive extended communities 150 Range Registration Procedures 151 ----------- ------------------------- 152 0x0000-8000 First Come First Served 153 0x8001-FFFF Standards Action/Early IANA Allocation 155 An application may need both a transitive and a non-transitive 156 community and it may be beneficial to have the same value for both 157 communities. (Note that both extended communities will still be 158 different as they will differ from their T bit). The IANA SHOULD try 159 to accommodate such request to get both a transitive and non- 160 transitive assigned community with the same value for both. 162 4. Security Considerations 164 This document defines IANA actions. In itself, it has no impact on 165 the security of the BGP protocol. 167 5. Normative References 169 [I-D.ietf-idr-as4octet-extcomm-generic-subtype] 170 Rao, D., Mohapatra, P., and J. Haas, "Generic Subtype for 171 BGP Four-octet AS specific extended community", 172 draft-ietf-idr-as4octet-extcomm-generic-subtype-03 (work 173 in progress), October 2010. 175 [RFC1997] Chandrasekeran, R., Traina, P., and T. Li, "BGP 176 Communities Attribute", RFC 1997, August 1996. 178 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 179 Requirement Levels", BCP 14, RFC 2119, March 1997. 181 [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended 182 Communities Attribute", RFC 4360, February 2006. 184 [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an 185 IANA Considerations Section in RFCs", BCP 26, RFC 5226, 186 May 2008. 188 Authors' Addresses 190 Bruno Decraene 191 France Telecom - Orange 192 38 rue du General Leclerc 193 Issy Moulineaux cedex 9 92794 194 France 196 Email: bruno.decraene@orange-ftgroup.com 198 Pierre Francois 199 Universite catholique de Louvain 200 Place Ste Barbe, 2 201 Louvain-la-Neuve 1348 202 BE 204 Email: francois@info.ucl.ac.be