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Haas, Ed. 3 Internet-Draft Juniper Networks 4 Updates: 5575 (if approved) April 11, 2015 5 Intended status: Standards Track 6 Expires: October 13, 2015 8 Clarification of the Flowspec Redirect Extended Community 9 draft-ietf-idr-flowspec-redirect-rt-bis-04 11 Abstract 13 This document updates RFC 5575 (Dissemination of Flow Specification 14 Rules) to clarify the formatting of the the BGP Flowspec Redirect 15 Extended Community. 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 October 13, 2015. 34 Copyright Notice 36 Copyright (c) 2015 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 52 2. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 53 2.1. Update to BGP Generic Transitive Experimental Use 54 Extended Community Sub-Types . . . . . . . . . . . . . . 4 55 2.2. Generic Transitive Experimental Extended Community Part 2 56 Sub-Types . . . . . . . . . . . . . . . . . . . . . . . . 5 57 2.3. Generic Transitive Experimental Extended Community Part 3 58 Sub-Types . . . . . . . . . . . . . . . . . . . . . . . . 5 59 3. Security Considerations . . . . . . . . . . . . . . . . . . . 6 60 4. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 6 61 5. Normative References . . . . . . . . . . . . . . . . . . . . 6 62 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 7 64 1. Introduction 66 Dissemination of Flow Specification Rules [RFC5575], commonly known 67 as BGP Flowspec, provided for a BGP Extended Community [RFC4360] that 68 served to redirect traffic to a VRF routing instance that matched the 69 flow specification NLRI. In that RFC, the Redirect Extended 70 Community was documented as follows: 72 : +--------+--------------------+--------------------------+ 73 : | type | extended community | encoding | 74 : +--------+--------------------+--------------------------+ 75 : | 0x8008 | redirect | 6-byte Route Target | 76 : +--------+--------------------+--------------------------+ 77 : 78 : [...] 79 : 80 : Redirect: The redirect extended community allows the traffic to be 81 : redirected to a VRF routing instance that lists the specified 82 : route-target in its import policy. If several local instances 83 : match this criteria, the choice between them is a local matter 84 : (for example, the instance with the lowest Route Distinguisher 85 : value can be elected). This extended community uses the same 86 : encoding as the Route Target extended community [RFC4360]. 87 : [...] 88 : 89 : 11. IANA Considerations 90 : [...] 91 : 92 : The following traffic filtering flow specification rules have been 93 : allocated by IANA from the "BGP Extended Communities Type - 94 : Experimental Use" registry as follows: 95 : [...] 96 : 97 : 0x8008 - Flow spec redirect 99 The IANA registry of BGP Extended Communities clearly identifies 100 communities of specific formats. For example, "Two-octet AS Specific 101 Extended Community" [RFC4360], "Four-octet AS Specific Extended 102 Community" [RFC5668] and "IPv4 Address Specific Extended Community" 103 [RFC4360]. Route Targets [RFC4360] identify this format in the high- 104 order (Type) octet of the Extended Community and set the value of the 105 low-order (Sub-Type) octet to 0x02. The Value field of the Route 106 Target Extended Community is intended to be interpreted in the 107 context of its format. 109 Since the Redirect Extended Community only registered a single code- 110 point in the IANA BGP Extended Community registry, a common 111 interpretation of the redirect extended community's "6-byte route 112 target" has been to look, at a receiving router, for a route target 113 value that matches the route target value in the received redirect 114 extended community, and import the advertised route to the 115 corresponding VRF instance subject to the rules defined in [RFC5575]. 116 However, because the route target format in the redirect extended 117 community is not clearly defined, the wrong match may occur. 119 This "value wildcard" matching behavior, which does not take into 120 account the format of the route target defined for a local VRF and 121 may result in the wrong matching decision, does not match deployed 122 implementations of BGP Flowspec. Deployed implementations of BGP 123 Flowspec solve this problem by defining different redirect extended 124 communities that are specific to the format of the route target 125 value. This document defines the following redirect extended 126 communities: 128 +--------+--------------------+-------------------------------------+ 129 | type | extended community | encoding | 130 +--------+--------------------+-------------------------------------+ 131 | 0x8008 | redirect AS-2byte | 2-octet AS, 4-octet Value | 132 | 0x8108 | redirect IPv4 | 4-octet IPv4 Address, 2-octet Value | 133 | 0x8208 | redirect AS-4byte | 4-octet AS, 2-octet Value | 134 +--------+--------------------+-------------------------------------+ 136 It should be noted that the low-order nibble of the Redirect's Type 137 field corresponds to the Route Target Extended Community format field 138 (Type). (See [RFC4360], Secs. 3.1, 3.2, and 4 plus [RFC5668], Sec. 139 2.) The low order octet (Sub-Type) of the Redirect Extended 140 Community remains 0x08, contrasted to 0x02 for Route Targets. 142 The IANA Registries for BGP Extended Communities [RFC7153] document 143 was written to update the previously-mentioned IANA registries to 144 better document BGP Extended Community formats. The IANA 145 Considerations section below further amends those registry updates in 146 order to properly document the Flowspec redirect communities. 148 2. IANA Considerations 150 2.1. Update to BGP Generic Transitive Experimental Use Extended 151 Community Sub-Types 153 IANA is requested to update the "BGP Generic Transitive Experimental 154 Use Extended Community Sub-Types" registry as follows: 156 0x08 - Flow spec redirect AS-2byte format. [RFC5575, RFC-to-be] 158 (Note to RFC Editor - replace RFC-to-be with this RFC number.) 160 IANA is requested to update the "BGP Transitive Extended Community 161 Types" registry as follows: 163 0x81 - Generic Transitive Experimental Use Extended Community 164 Part 2 (Sub-Types are defined in the "Generic Transitive 165 Experimental Extended Community Part 2 Sub-Types" Registry) 166 0x82 - Generic Transitive Experimental Use Extended Community 167 Part 3 (Sub-Types are defined in the "Generic Transitive 168 Experimental Extended Community Part 3 Sub-Types" Registry) 170 2.2. Generic Transitive Experimental Extended Community Part 2 Sub- 171 Types 173 IANA is requested to create the "Generic Transitive Experimental Use 174 Extended Community Part 2 Sub-Types" registry. This registry should 175 be created under the BGP Extended Communities registry. It will 176 contain the following note: 178 This registry contains values of the second octet (the "Sub-Type" 179 field) of an extended community when the value of the first octet 180 (the "Type" field) is 0x81. 182 Registry Name: Generic Transitive Experimental Use Extended Community 183 Part 2 Sub-Types 185 RANGE REGISTRATION PROCEDURE REFERENCE 187 0x00-0xBF First Come First Served 188 0xC0-0xFF IETF Review 190 SUB-TYPE VALUE NAME 191 0x00-0x07 Unassigned 192 0x08 Flow spec redirect IPv4 format. [RFC-to-be] 193 0x09-0xff Unassigned 195 (Note to RFC Editor - replace RFC-to-be with this RFC number.) 197 2.3. Generic Transitive Experimental Extended Community Part 3 Sub- 198 Types 200 IANA is requested to create the "Generic Transitive Experimental Use 201 Extended Community Part 3 Sub-Types" registry. This registry should 202 be created under the BGP Extended Communities registry. It will 203 contain the following note: 205 This registry contains values of the second octet (the "Sub-Type" 206 field) of an extended community when the value of the first octet 207 (the "Type" field) is 0x82. 209 Registry Name: Generic Transitive Experimental Use Extended Community 210 Part 2 Sub-Types 211 RANGE REGISTRATION PROCEDURE REFERENCE 213 0x00-0xBF First Come First Served 214 0xC0-0xFF IETF Review 216 SUB-TYPE VALUE NAME 217 0x00-0x07 Unassigned 218 0x08 Flow spec redirect AS-4byte format. [RFC-to-be] 219 0x09-0xff Unassigned 221 (Note to RFC Editor - replace RFC-to-be with this RFC number.) 223 3. Security Considerations 225 This document introduces no additional security considerations than 226 those already covered in [RFC5575]. It should be noted that if the 227 wildcard behavior were actually implemented, this ambiguity may lead 228 to the installation of Flowspec rules in an incorrect VRF and may 229 lead to traffic to be incorrectly delivered. 231 4. Acknowledgements 233 The contents of this document was raised as part of implementation 234 discussions of BGP Flowspec with the following individuals: 236 Andrew Karch (Cisco) 238 Robert Raszuk 240 Adam Simpson (Alcatel-Lucent) 242 Matthieu Texier (Arbor Networks) 244 Kaliraj Vairavakkalai (Juniper) 246 5. Normative References 248 [RFC4360] Sangli, S., Tappan, D., and Y. Rekhter, "BGP Extended 249 Communities Attribute", RFC 4360, February 2006. 251 [RFC5575] Marques, P., Sheth, N., Raszuk, R., Greene, B., Mauch, J., 252 and D. McPherson, "Dissemination of Flow Specification 253 Rules", RFC 5575, August 2009. 255 [RFC5668] Rekhter, Y., Sangli, S., and D. Tappan, "4-Octet AS 256 Specific BGP Extended Community", RFC 5668, October 2009. 258 [RFC7153] Rosen, E. and Y. Rekhter, "IANA Registries for BGP 259 Extended Communities", RFC 7153, March 2014. 261 Author's Address 263 Jeffrey Haas (editor) 264 Juniper Networks 266 Email: jhaas@juniper.net