idnits 2.17.1 draft-zhou-idr-bgp-srmpls-elp-01.txt: Checking boilerplate required by RFC 5378 and the IETF Trust (see https://trustee.ietf.org/license-info): ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/1id-guidelines.txt: ---------------------------------------------------------------------------- No issues found here. Checking nits according to https://www.ietf.org/id-info/checklist : ---------------------------------------------------------------------------- ** The document seems to lack a Security Considerations section. ** The document seems to lack a both a reference to RFC 2119 and the recommended RFC 2119 boilerplate, even if it appears to use RFC 2119 keywords. RFC 2119 keyword, line 65: '...< ELI, EL> pairs SHOULD be inserted in...' RFC 2119 keyword, line 89: '...< ELI, EL> pairs SHOULD be inserted in...' RFC 2119 keyword, line 92: '...serted positions SHOULD be whithin the...' RFC 2119 keyword, line 95: '...< ELI, EL> pairs SHOULD be inserted wh...' RFC 2119 keyword, line 135: '... ELI, EL> pairs SHOULD be inserted in...' Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (August 21, 2020) is 1338 days in the past. Is this intentional? Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Unused Reference: 'RFC6790' is defined on line 162, but no explicit reference was found in the text == Outdated reference: A later version (-26) exists of draft-ietf-idr-segment-routing-te-policy-09 Summary: 2 errors (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 IDR Working Group Yao. Liu 3 Internet-Draft Shaofu. Peng 4 Intended status: Standards Track ZTE Corp. 5 Expires: February 22, 2021 August 21, 2020 7 BGP Extension for SR-MPLS Entropy Label Position 8 draft-zhou-idr-bgp-srmpls-elp-01 10 Abstract 12 This document proposed an extension for BGP to configure the entropy 13 label position for SR-MPLS networks. 15 Status of This Memo 17 This Internet-Draft is submitted in full conformance with the 18 provisions of BCP 78 and BCP 79. 20 Internet-Drafts are working documents of the Internet Engineering 21 Task Force (IETF). Note that other groups may also distribute 22 working documents as Internet-Drafts. The list of current Internet- 23 Drafts is at https://datatracker.ietf.org/drafts/current/. 25 Internet-Drafts are draft documents valid for a maximum of six months 26 and may be updated, replaced, or obsoleted by other documents at any 27 time. It is inappropriate to use Internet-Drafts as reference 28 material or to cite them other than as "work in progress." 30 This Internet-Draft will expire on February 22, 2021. 32 Copyright Notice 34 Copyright (c) 2020 IETF Trust and the persons identified as the 35 document authors. All rights reserved. 37 This document is subject to BCP 78 and the IETF Trust's Legal 38 Provisions Relating to IETF Documents 39 (https://trustee.ietf.org/license-info) in effect on the date of 40 publication of this document. Please review these documents 41 carefully, as they describe your rights and restrictions with respect 42 to this document. Code Components extracted from this document must 43 include Simplified BSD License text as described in Section 4.e of 44 the Trust Legal Provisions and are provided without warranty as 45 described in the Simplified BSD License. 47 Internet-DrafBGP Extension for SR-MPLS Entropy Label Positio August 2020 49 Table of Contents 51 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 52 2. Entropy Labels in SR-MPLS Scenario with a Controller . . . . 2 53 3. BGP Extensions . . . . . . . . . . . . . . . . . . . . . . . 3 54 4. Operations . . . . . . . . . . . . . . . . . . . . . . . . . 3 55 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 56 6. Normative References . . . . . . . . . . . . . . . . . . . . 4 57 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 59 1. Introduction 61 Entropy Label(EL) [RFC6790]is a technology that can be used for load- 62 balancing in Segment Routing (SR) MPLS. 64 [RFC8662] proposes to use entropy labels for SR-MPLS networks and 65 mutiple < ELI, EL> pairs SHOULD be inserted in the SR-MPLS label 66 stack. The ingress node may decide the number and position of the 67 ELI/ELs which need to be inserted into the label stack, that is 68 termed as ELP (Entropy Label Position). In some cases, the 69 controller is used to perform the TE path computation for intra or 70 inter-domain scenarios, thus it is also the responsibility of the 71 controller to calculate ELP and inform it to the headend of the SR-TE 72 path. 74 [I-D.ietf-idr-segment-routing-te-policy] defines the specific process 75 of how the controller in the SR network passes the path calculation 76 result of the SR-TE policy to the headend of the network through BGP. 78 In this document, the ELP information is transmitted by extending the 79 flags of Segment List Sub-TLV in the BGP. 81 2. Entropy Labels in SR-MPLS Scenario with a Controller 83 [RFC8662] proposes to use entropy labels for SR-MPLS networks. The 84 Entropy Readable Label Depth (ERLD) is defined as the number of 85 labels which means that the router will perform load-balancing using 86 the ELI/EL. An appropriate algorithm should consider the following 87 criteria: 89 o a limited number of < ELI, EL> pairs SHOULD be inserted in the SR- 90 MPLS label stack; 92 o the inserted positions SHOULD be whithin the ERLD of a maximize 93 number of transit LSRs; 95 o a minimum number of < ELI, EL> pairs SHOULD be inserted while 96 satisfying the above criteria. 98 Internet-DrafBGP Extension for SR-MPLS Entropy Label Positio August 2020 100 As shown in Figure 1 , in SR-MPLS inter-domain scenario, the 101 controller may perform the computation of the end-to-end path as well 102 as the the Entropy Label Position (ELP) including the number and the 103 position of the ELI/ELs. The controller has the capability to get 104 the ERLD information of all nodes in inter-domain scenarios. 106 .................... .................... ..................... 107 . . . . . . 108 .+---+ +---+ . . +---+ +---+ . .+---+ +----+ . 109 .| A |-------| B |------ | C |------| X |-------| Y |------| Z | . 110 .+---+ +---+ . . +---+ +---+ . .+---+ +----+ . 111 . domain 1 . . domain 2 . . domain 3 . 112 .................... .................... ..................... 114 Figure 1: Entropy Labels in SR-MPLS Inter-Domain Scenario 116 3. BGP Extensions 118 The Segment Flags is defined in Section 2.4.3.2.12 of 119 [I-D.ietf-idr-segment-routing-te-policy]. 121 0 1 2 3 4 5 6 7 122 +-+-+-+-+-+-+-+-+ 123 |V|A|E| | 124 +-+-+-+-+-+-+-+-+ 126 E-Flag: This flag indicates that presence of < ELI, EL> label pairs 127 are inserted after this segment. It is applicable to all SR-MPLS 128 Segment Types. 130 4. Operations 132 Supposed the head end had received a SR-TE path from the controller 133 with multiple Segment List Sub-TLVs, for example, , especially S3 and S6 with E-flag. It indicates that two < 135 ELI, EL> pairs SHOULD be inserted into the label stack of the SR-TE 136 forwarding entry, respectively after the Label for S3 and Label for 137 S6. With EL information, the label stack for SR-MPLS would be 138 . 140 Note that the value of EL is supplemented by headend, according to 141 load-balancing function of the appropriate keys extracted from a 142 given packet. 144 Internet-DrafBGP Extension for SR-MPLS Entropy Label Positio August 2020 146 5. IANA Considerations 148 This document requests bit 2 for Entropy Label Flag. 150 Bit Description Reference 151 ------------------------------------------------------------------ 152 2 Entropy Label Position Flag(E-Flag) This document 154 6. Normative References 156 [I-D.ietf-idr-segment-routing-te-policy] 157 Previdi, S., Filsfils, C., Talaulikar, K., Mattes, P., 158 Rosen, E., Jain, D., and S. Lin, "Advertising Segment 159 Routing Policies in BGP", draft-ietf-idr-segment-routing- 160 te-policy-09 (work in progress), May 2020. 162 [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and 163 L. Yong, "The Use of Entropy Labels in MPLS Forwarding", 164 RFC 6790, DOI 10.17487/RFC6790, November 2012, 165 . 167 [RFC8662] Kini, S., Kompella, K., Sivabalan, S., Litkowski, S., 168 Shakir, R., and J. Tantsura, "Entropy Label for Source 169 Packet Routing in Networking (SPRING) Tunnels", RFC 8662, 170 DOI 10.17487/RFC8662, December 2019, 171 . 173 Authors' Addresses 175 Liu Yao 176 ZTE Corp. 178 Email: liu.yao71@zte.com.cn 180 Peng Shaofu 181 ZTE Corp. 183 Email: peng.shaofu@zte.com.cn