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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-08) exists of draft-ietf-idr-custom-decision-05 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group A. Retana 3 Internet-Draft A. Kapoor 4 Intended status: Informational K. Patel 5 Expires: April 27, 2015 Cisco Systems, Inc. 6 October 24, 2014 8 Use of the Cost Community to carry the Accumulated IGP Metric 9 draft-retana-idr-aigp-cost-community-01 11 Abstract 13 This document explains the use of the Cost Community to flexibly 14 carry the Accumulated IGP Metric. 16 Status of This Memo 18 This Internet-Draft is submitted in full conformance with the 19 provisions of BCP 78 and BCP 79. 21 Internet-Drafts are working documents of the Internet Engineering 22 Task Force (IETF). Note that other groups may also distribute 23 working documents as Internet-Drafts. The list of current Internet- 24 Drafts is at http://datatracker.ietf.org/drafts/current/. 26 Internet-Drafts are draft documents valid for a maximum of six months 27 and may be updated, replaced, or obsoleted by other documents at any 28 time. It is inappropriate to use Internet-Drafts as reference 29 material or to cite them other than as "work in progress." 31 This Internet-Draft will expire on April 27, 2015. 33 Copyright Notice 35 Copyright (c) 2014 IETF Trust and the persons identified as the 36 document authors. All rights reserved. 38 This document is subject to BCP 78 and the IETF Trust's Legal 39 Provisions Relating to IETF Documents 40 (http://trustee.ietf.org/license-info) in effect on the date of 41 publication of this document. Please review these documents 42 carefully, as they describe your rights and restrictions with respect 43 to this document. Code Components extracted from this document must 44 include Simplified BSD License text as described in Section 4.e of 45 the Trust Legal Provisions and are provided without warranty as 46 described in the Simplified BSD License. 48 Table of Contents 50 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 51 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2 52 3. Use of the Cost Community to carry the AIGP . . . . . . . . . 2 53 4. Security Considerations . . . . . . . . . . . . . . . . . . . 3 54 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 55 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3 56 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 3 57 7.1. Normative References . . . . . . . . . . . . . . . . . . 3 58 7.2. Informative References . . . . . . . . . . . . . . . . . 3 59 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 3 61 1. Introduction 63 The Accumulated IGP Metric (AIGP) Attribute [RFC7311] has been 64 defined with the purpose of carrying an AIGP. The attribute is used 65 in the BGP selection process before the tie braking procedures 66 [RFC4271], effectively after the LOCAL_PREF comparison. 68 The Cost Community [I-D.ietf-idr-custom-decision] can provide a 69 flexible mechanism to carry the AIGP. It can se used both at a 70 different point in the selection process, or as a direct replacement 71 for the AIGP attribute in networks that don't fully support it. 73 2. Requirements Language 75 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 76 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 77 document are to be interpreted as described in [RFC2119]. 79 3. Use of the Cost Community to carry the AIGP 81 The applicability and procedures defined in [RFC7311] for originating 82 and modifying the AIGP value are not changed in this document. The 83 value is used as the Cost of the Cost Community. 85 The Point of Insertion (POI) can be set to any of the values defined 86 in [I-D.ietf-idr-custom-decision]. Note that the use of the 87 LOCAL_PREF POI is equivalent to using the AIGP Attribute in routers 88 that don't support it. 90 If the Cost Community is used to carry the AIGP value, then the AIGP 91 Attribute SHOULD NOT be used. If used, then the high-order bit of 92 the Community-ID MUST be set in a Cost Community with a POI of AIGP 93 to avoid an inconsistent selection process. Note that this operation 94 doesn't preclude using a Cost Community with a Cost of the AIGP at a 95 different POI. 97 4. Security Considerations 99 This document explains the use of the Cost Community to provide 100 flexibility in the application of routing policy related to the 101 accumulated IGP metric of a route. As such, it does not introduce 102 new security risks than the ones considered in 103 [I-D.ietf-idr-custom-decision] or [RFC7311]. 105 5. IANA Considerations 107 This document has no IANA actions. 109 6. Acknowledgements 111 TBD 113 7. References 115 7.1. Normative References 117 [I-D.ietf-idr-custom-decision] 118 Retana, A. and R. White, "BGP Custom Decision Process", 119 draft-ietf-idr-custom-decision-05 (work in progress), 120 October 2014. 122 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 123 Requirement Levels", BCP 14, RFC 2119, March 1997. 125 [RFC7311] Mohapatra, P., Fernando, R., Rosen, E., and J. Uttaro, 126 "The Accumulated IGP Metric Attribute for BGP", RFC 7311, 127 August 2014. 129 7.2. Informative References 131 [RFC4271] Rekhter, Y., Li, T., and S. Hares, "A Border Gateway 132 Protocol 4 (BGP-4)", RFC 4271, January 2006. 134 Authors' Addresses 136 Alvaro Retana 137 Cisco Systems, Inc. 138 7025 Kit Creek Rd. 139 Research Triangle Park, NC 27709 140 USA 142 Email: aretana@cisco.com 143 Anoop Kapoor 144 Cisco Systems, Inc. 145 170 Tasman Drive 146 San Jose, CA 95134 147 USA 149 Email: ankapoor@cisco.com 151 Keyur Patel 152 Cisco Systems, Inc. 153 170 Tasman Drive 154 San Jose, CA 95134 155 USA 157 Email: keyupate@cisco.com