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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-00 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 is 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 each subobject has an attribute 141 called 'L bit', which is set if the subobject represents a loose hop. 143 If the bit is not set, the subobject represents a strict hop. The 144 interpretation of Loose bit (L bit) is as per section 4.3.3.1 of 145 [RFC3209]. 147 3. Other Considerations 149 Based on the survey, it should be noted that most implementation 150 already support the update in the IRO specification as per this 151 document. The other implementation are expected to make an update to 152 the IRO procedures. 154 4. Security Considerations 156 This update in IRO specification does not introduce any new security 157 considerations, apart from those mentioned in [RFC5440]. 158 Clarification in the supported IRO ordering or Loose bit handling 159 will not have any negative security impact. 161 It is worth noting that PCEP operates over TCP. An analysis of the 162 security issues for routing protocols that use TCP (including PCEP) 163 is provided in [RFC6952], while [I-D.ietf-pce-pceps] discusses an 164 experimental approach to provide secure transport for PCEP. 166 5. IANA Considerations 168 This informational document makes no requests to IANA for action. 170 6. Acknowledgments 172 A special thanks to PCE chairs for guidance regarding this work. 174 Thanks to Francesco Fondelli for his suggestions in clarifying the L 175 bit usage. 177 7. References 179 7.1. Normative References 181 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 182 Requirement Levels", BCP 14, RFC 2119, March 1997. 184 [RFC5440] Vasseur, JP. and JL. Le Roux, "Path Computation Element 185 (PCE) Communication Protocol (PCEP)", RFC 5440, March 186 2009. 188 7.2. Informative References 190 [RFC3209] Awduche, D., Berger, L., Gan, D., Li, T., Srinivasan, V., 191 and G. Swallow, "RSVP-TE: Extensions to RSVP for LSP 192 Tunnels", RFC 3209, December 2001. 194 [RFC5441] Vasseur, JP., Zhang, R., Bitar, N., and JL. Le Roux, "A 195 Backward-Recursive PCE-Based Computation (BRPC) Procedure 196 to Compute Shortest Constrained Inter-Domain Traffic 197 Engineering Label Switched Paths", RFC 5441, April 2009. 199 [RFC6952] Jethanandani, M., Patel, K., and L. Zheng, "Analysis of 200 BGP, LDP, PCEP, and MSDP Issues According to the Keying 201 and Authentication for Routing Protocols (KARP) Design 202 Guide", RFC 6952, May 2013. 204 [I-D.ietf-pce-pcep-domain-sequence] 205 Dhody, D., Palle, U., and R. Casellas, "Standard 206 Representation of Domain-Sequence", draft-ietf-pce-pcep- 207 domain-sequence-07 (work in progress), December 2014. 209 [I-D.ietf-pce-pceps] 210 Lopez, D., Dios, O., Wu, W., and D. Dhody, "Secure 211 Transport for PCEP", draft-ietf-pce-pceps-03 (work in 212 progress), March 2015. 214 [I-D.dhody-pce-iro-survey] 215 Dhody, D., "Informal Survey into Include Route Object 216 (IRO) Implementations in Path Computation Element 217 communication Protocol (PCEP)", draft-dhody-pce-iro- 218 survey-02 (work in progress), December 2014. 220 Appendix A. Details of IRO survey 222 During discussions of this document to provide a standard 223 representation and encoding of Domain-Sequence within PCEP. It was 224 determined that there was a need for clarification with respect to 225 the ordered nature of the IRO. 227 Since there was a proposal to have a new IRO type with ordering, as 228 well as handling of Loose bit, in an earlier version of this document 229 (refer - draft-ietf-pce-pcep-domain-sequence-05), it was deemed 230 necessary to conduct a survey of the existing and planned 231 implementations. An informal survey was conducted via email. 232 Responses were collected and anonymized by the PCE working group 233 chairs. 235 [I-D.dhody-pce-iro-survey] summarizes the survey questions and 236 captures the results. It further list some conclusions and action 237 points. 239 This document was considered as one possible venue to handle the 240 proposed action points. 242 Author's Address 244 Dhruv Dhody 245 Huawei Technologies 246 Leela Palace 247 Bangalore, Karnataka 560008 248 India 250 EMail: dhruv.ietf@gmail.com