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Dhody 3 Internet-Draft Huawei Technologies 4 Updates: 5440 (if approved) November 16, 2015 5 Intended status: Standards Track 6 Expires: May 19, 2016 8 Update to Include Route Object (IRO) specification in Path Computation 9 Element communication Protocol (PCEP) 10 draft-ietf-pce-iro-update-03 12 Abstract 14 During discussions of a document to provide a standard representation 15 and encoding of Domain-Sequence within the Path Computation Element 16 (PCE) communication Protocol (PCEP) for communications between a Path 17 Computation Client (PCC) and a PCE, or between two PCEs, it was 18 determined that there was a need for clarification with respect to 19 the ordered nature of the Include Route Object (IRO). 21 An informal survey was conducted to determine the state of current 22 and planned implementation with respect to IRO ordering and handling 23 of Loose bit (L bit). 25 This document updates the IRO specification of RFC 5440 based on the 26 survey conclusion and recommendation. 28 Status of This Memo 30 This Internet-Draft is submitted in full conformance with the 31 provisions of BCP 78 and BCP 79. 33 Internet-Drafts are working documents of the Internet Engineering 34 Task Force (IETF). Note that other groups may also distribute 35 working documents as Internet-Drafts. The list of current Internet- 36 Drafts is at http://datatracker.ietf.org/drafts/current/. 38 Internet-Drafts are draft documents valid for a maximum of six months 39 and may be updated, replaced, or obsoleted by other documents at any 40 time. It is inappropriate to use Internet-Drafts as reference 41 material or to cite them other than as "work in progress." 43 This Internet-Draft will expire on May 19, 2016. 45 Copyright Notice 47 Copyright (c) 2015 IETF Trust and the persons identified as the 48 document authors. All rights reserved. 50 This document is subject to BCP 78 and the IETF Trust's Legal 51 Provisions Relating to IETF Documents 52 (http://trustee.ietf.org/license-info) in effect on the date of 53 publication of this document. Please review these documents 54 carefully, as they describe your rights and restrictions with respect 55 to this document. Code Components extracted from this document must 56 include Simplified BSD License text as described in Section 4.e of 57 the Trust Legal Provisions and are provided without warranty as 58 described in the Simplified BSD License. 60 Table of Contents 62 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 63 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 64 2. Update in IRO specification . . . . . . . . . . . . . . . . . 3 65 3. Other Considerations . . . . . . . . . . . . . . . . . . . . 4 66 4. Security Considerations . . . . . . . . . . . . . . . . . . . 4 67 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 68 6. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 4 69 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 70 7.1. Normative References . . . . . . . . . . . . . . . . . . 4 71 7.2. Informative References . . . . . . . . . . . . . . . . . 5 72 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 74 1. Introduction 76 The Path Computation Element Communication Protocol (PCEP) provides 77 mechanisms for Path Computation Elements (PCEs) to perform path 78 computations in response to Path Computation Clients (PCCs) requests. 80 [RFC5440] defines the Include Route Object (IRO) to specify network 81 elements to be traversed in the computed path. The specification did 82 not mention if IRO is an ordered or un-ordered list of sub-objects. 83 It mentioned that the Loose bit (L bit) has no meaning within an IRO. 85 [RFC5441] suggested the use of IRO to indicate the sequence of 86 domains to be traversed during inter-domain path computation. 88 In order to discover the current state of affairs amongst 89 implementations a survey of the existing and planned implementations 90 was conducted. This survey [I-D.dhody-pce-iro-survey] was informal 91 and conducted via email. Responses were collected and anonymized by 92 the PCE working group chair. 94 During discussion of [I-D.ietf-pce-pcep-domain-sequence] it was 95 proposed to have a new IRO type with ordered nature, as well as 96 handling of Loose bit (L bit); however, with the update to [RFC5440] 97 described in this document, no new IRO type is needed. 99 This document updates the IRO specifications in section 7.12 of 100 [RFC5440] as per the conclusion and action points presented in 101 [I-D.dhody-pce-iro-survey]. 103 1.1. Requirements Language 105 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 106 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 107 document are to be interpreted as described in [RFC2119]. 109 2. Update in IRO specification 111 Section 7.12 of [RFC5440] describes IRO as an optional object used to 112 specify a set of network elements to be traversed in the computed 113 path. It also states that the Loose bit (L bit) in sub-object has no 114 meaning within an IRO. It did not mention if IRO is an ordered or 115 un-ordered list of sub-objects. 117 A survey of the existing and planned implementations was conducted in 118 order to discover the current state of affairs amongst 119 implementations. [I-D.dhody-pce-iro-survey] describe the 120 questionnaire, results and presents some conclusions and proposed 121 action items. 123 The survey suggest that most implementations construct or interpret 124 IRO in an ordered fashion and consider it to be an ordered list. 125 More than half of implementation under survey consider the IRO sub- 126 objects as strict hops, others consider loose or support both. The 127 results shown in this survey seems to suggest that most 128 implementations would be fine with updating [RFC5440] to specify IRO 129 as an ordered list as well as to enable support for Loose bit (L bit) 130 such that both strict and loose hops could be supported in the IRO. 132 This document thus updates [RFC5440] regarding the IRO specification 133 and is intended to replace the last line in section 7.12 of 134 [RFC5440], that states - 136 "The L bit of such sub-object has no meaning within an IRO." 138 As per the update in this document, the L Bit of IRO sub-object is 139 set based on the loose or strict property of the sub-object, which is 140 set if the sub-object represents a loose hop. If the bit is not set, 141 the sub-object represents a strict hop. The interpretation of Loose 142 bit (L bit) is as per section 4.3.3.1 of [RFC3209]. 144 Also, as per the update in this document, the content of IRO is an 145 ordered list of sub-objects representing a series of abstract nodes. 146 An abstract node could just be a simple abstract node comprising one 147 node or a group of nodes for example an AS (comprising of multiple 148 hops within the AS) (refer section 4.3.2 of [RFC3209]). 150 3. Other Considerations 152 Based on the survey, it should be noted that most implementation 153 already support the update in the IRO specification as per this 154 document. The other implementation are expected to make an update to 155 the IRO procedures. 157 4. Security Considerations 159 This update in IRO specification does not introduce any new security 160 considerations, apart from those mentioned in [RFC5440]. 161 Clarification in the supported IRO ordering or Loose bit handling 162 will not have any negative security impact. 164 It is worth noting that PCEP operates over TCP. An analysis of the 165 security issues for routing protocols that use TCP (including PCEP) 166 is provided in [RFC6952], while [I-D.ietf-pce-pceps] discusses an 167 experimental approach to provide secure transport for PCEP. 169 5. IANA Considerations 171 This document makes no requests to IANA for action. 173 6. Acknowledgments 175 A special thanks to PCE chairs for guidance regarding this work. 177 Thanks to Francesco Fondelli for his suggestions in clarifying the L 178 bit usage. 180 Thanks to Adrian Farrel for his review and comments. 182 7. References 184 7.1. Normative References 186 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 187 Requirement Levels", BCP 14, RFC 2119, 188 DOI 10.17487/RFC2119, March 1997, 189 . 191 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 192 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 193 Tunnels", RFC 3209, DOI 10.17487/RFC3209, December 2001, 194 . 196 [RFC5440] Vasseur, JP., Ed. and JL. Le Roux, Ed., "Path Computation 197 Element (PCE) Communication Protocol (PCEP)", RFC 5440, 198 DOI 10.17487/RFC5440, March 2009, 199 . 201 7.2. Informative References 203 [RFC5441] Vasseur, JP., Ed., Zhang, R., Bitar, N., and JL. Le Roux, 204 "A Backward-Recursive PCE-Based Computation (BRPC) 205 Procedure to Compute Shortest Constrained Inter-Domain 206 Traffic Engineering Label Switched Paths", RFC 5441, 207 DOI 10.17487/RFC5441, April 2009, 208 . 210 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 211 BGP, LDP, PCEP, and MSDP Issues According to the Keying 212 and Authentication for Routing Protocols (KARP) Design 213 Guide", RFC 6952, DOI 10.17487/RFC6952, May 2013, 214 . 216 [I-D.ietf-pce-pcep-domain-sequence] 217 Dhody, D., Palle, U., and R. Casellas, "Standard 218 Representation of Domain-Sequence", draft-ietf-pce-pcep- 219 domain-sequence-09 (work in progress), September 2015. 221 [I-D.ietf-pce-pceps] 222 Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure 223 Transport for PCEP", draft-ietf-pce-pceps-05 (work in 224 progress), November 2015. 226 [I-D.dhody-pce-iro-survey] 227 Dhody, D., "Informal Survey into Include Route Object 228 (IRO) Implementations in Path Computation Element 229 communication Protocol (PCEP)", draft-dhody-pce-iro- 230 survey-02 (work in progress), December 2014. 232 Author's Address 234 Dhruv Dhody 235 Huawei Technologies 236 Divyashree Techno Park, Whitefield 237 Bangalore, Karnataka 560037 238 India 240 EMail: dhruv.ietf@gmail.com