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Dhody 3 Internet-Draft Huawei Technologies 4 Updates: 5440 (if approved) March 6, 2015 5 Intended status: Standards Track 6 Expires: September 7, 2015 8 Update to Include Route Object (IRO) specification in Path Computation 9 Element communication Protocol (PCEP) 10 draft-ietf-pce-iro-update-01 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 based on the survey 26 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 September 7, 2015. 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 Appendix A. Details of IRO survey . . . . . . . . . . . . . . . 6 73 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . 6 75 1. Introduction 77 The Path Computation Element Communication Protocol (PCEP) provides 78 mechanisms for Path Computation Elements (PCEs) to perform path 79 computations in response to Path Computation Clients (PCCs) requests. 81 [RFC5440] defines the Include Route Object (IRO) to specify that the 82 computed path must traverse a set of specified network elements. The 83 specification did not mention if IRO is an ordered or un-ordered list 84 of sub-objects. It mentioned that the Loose bit (L bit) has no 85 meaning within an IRO. 87 [RFC5441] suggested the use of IRO to indicate the sequence of 88 domains to be traversed during inter-domain path computation. 90 During discussion of [I-D.ietf-pce-pcep-domain-sequence] it was 91 proposed to have a new IRO type with ordered nature, as well as 92 handling of Loose bit (L bit). 94 In order to discover the current state of affairs amongst 95 implementations a survey of the existing and planned implementations 96 was conducted. This survey [I-D.dhody-pce-iro-survey] was informal 97 and conducted via email. Responses were collected and anonymized by 98 the PCE working group chair. 100 This document updates the IRO specifications in [RFC5440] as per the 101 conclusion and action points presented in [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 [RFC5440] describes IRO as an optional object used to specify that 112 the computed path MUST traverse a set of specified network elements. 113 It further state that the Loose bit (L bit) of such 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. More details in Appendix A. 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 making IRO as an ordered list as well as support for Loose bit (L 134 bit). 136 The content of an IRO object MUST be an ordered list of subobjects 137 representing a series of abstract nodes. An abstract node may just 138 be a simple abstract node comprising one node or a group of nodes for 139 example an AS (comprising of multiple hops within the AS) (refer 140 [RFC3209] for details). Further, the loose or strict property of the 141 subobject MUST be interpreted based on L bit, which is set if the 142 subobject represents a loose hop. If the bit is not set, the 143 subobject represents a strict hop. The interpretation of Loose bit 144 (L bit) is as per section 4.3.3.1 of [RFC3209]. 146 3. Other Considerations 148 Based on the survey, it should be noted that most implementation 149 already support the update in the IRO specification as per this 150 document. The other implementation are expected to make an update to 151 the IRO procedures. 153 4. Security Considerations 155 This update in IRO specification does not introduce any new security 156 considerations, apart from those mentioned in [RFC5440]. 157 Clarification in the supported IRO ordering or Loose bit handling 158 will not have any negative security impact. 160 It is worth noting that PCEP operates over TCP. An analysis of the 161 security issues for routing protocols that use TCP (including PCEP) 162 is provided in [RFC6952], while [I-D.ietf-pce-pceps] discusses an 163 experimental approach to provide secure transport for PCEP. 165 5. IANA Considerations 167 This informational document makes no requests to IANA for action. 169 6. Acknowledgments 171 A special thanks to PCE chairs for guidance regarding this work. 173 Thanks to Francesco Fondelli for his suggestions in clarifying the L 174 bit usage. 176 7. References 178 7.1. Normative References 180 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 181 Requirement Levels", BCP 14, RFC 2119, March 1997. 183 [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element 184 (PCE) Communication Protocol (PCEP)", RFC 5440, March 185 2009. 187 7.2. Informative References 189 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 190 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 191 Tunnels", RFC 3209, December 2001. 193 [RFC5441] Vasseur, JP., Zhang, R., Bitar, N., and JL. Le Roux, "A 194 Backward-Recursive PCE-Based Computation (BRPC) Procedure 195 to Compute Shortest Constrained Inter-Domain Traffic 196 Engineering Label Switched Paths", RFC 5441, April 2009. 198 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 199 BGP, LDP, PCEP, and MSDP Issues According to the Keying 200 and Authentication for Routing Protocols (KARP) Design 201 Guide", RFC 6952, May 2013. 203 [I-D.ietf-pce-pcep-domain-sequence] 204 Dhody, D., Palle, U., and R. Casellas, "Standard 205 Representation of Domain-Sequence", draft-ietf-pce-pcep- 206 domain-sequence-07 (work in progress), December 2014. 208 [I-D.ietf-pce-pceps] 209 Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure 210 Transport for PCEP", draft-ietf-pce-pceps-03 (work in 211 progress), March 2015. 213 [I-D.dhody-pce-iro-survey] 214 Dhody, D., "Informal Survey into Include Route Object 215 (IRO) Implementations in Path Computation Element 216 communication Protocol (PCEP)", draft-dhody-pce-iro- 217 survey-02 (work in progress), December 2014. 219 Appendix A. Details of IRO survey 221 During discussions of this document to provide a standard 222 representation and encoding of Domain-Sequence within PCEP. It was 223 determined that there was a need for clarification with respect to 224 the ordered nature of the IRO. 226 Since there was a proposal to have a new IRO type with ordering, as 227 well as handling of Loose bit, in an earlier version of this document 228 (refer - draft-ietf-pce-pcep-domain-sequence-05), it was deemed 229 necessary to conduct a survey of the existing and planned 230 implementations. An informal survey was conducted via email. 231 Responses were collected and anonymized by the PCE working group 232 chairs. 234 [I-D.dhody-pce-iro-survey] summarizes the survey questions and 235 captures the results. It further list some conclusions and action 236 points. 238 This document was considered as one possible venue to handle the 239 proposed action points. 241 Author's Address 243 Dhruv Dhody 244 Huawei Technologies 245 Divyashree Techno Park, Whitefield 246 Bangalore, Karnataka 560037 247 India 249 EMail: dhruv.ietf@gmail.com