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RFC 2119 keyword, line 87: '... defined in [RFC8754]. The ingress PE MAY also classify the packet...' RFC 2119 keyword, line 113: '... specification SHOULD support the ba...' RFC 2119 keyword, line 123: '...e, or desirable, an implementation MAY...' RFC 2119 keyword, line 129: '.... This solution MAY be complemented w...' RFC 2119 keyword, line 133: '... SHOULD be used for queue selection....' Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (July 12, 2021) is 1019 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) No issues found here. Summary: 3 errors (**), 0 flaws (~~), 1 warning (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 SPRING C. Filsfils, Ed. 3 Internet-Draft F. Clad, Ed. 4 Intended status: Standards Track P. Camarillo 5 Expires: January 13, 2022 K. Raza 6 Cisco Systems, Inc. 7 July 12, 2021 9 Stateless and Scalable Network Slice Identification for SRv6 10 draft-filsfils-spring-srv6-stateless-slice-id-03 12 Abstract 14 This document defines a stateless and scalable solution to achieve 15 network slicing with SRv6. 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 https://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 January 13, 2022. 34 Copyright Notice 36 Copyright (c) 2021 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 (https://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. Slice Identifier . . . . . . . . . . . . . . . . . . . . . . 2 53 3. Ingress PE SLID Assignment . . . . . . . . . . . . . . . . . 2 54 4. Per-Slice Forwarding . . . . . . . . . . . . . . . . . . . . 3 55 5. Bandwidth-Allocation Slice . . . . . . . . . . . . . . . . . 3 56 6. Backward Compatibility . . . . . . . . . . . . . . . . . . . 3 57 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 4 58 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 59 8.1. Normative References . . . . . . . . . . . . . . . . . . 4 60 8.2. Informative References . . . . . . . . . . . . . . . . . 4 61 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 63 1. Introduction 65 SRv6 Network Programming[RFC8986] enables the creation of overlays 66 with underlay optimization to be deployed in an SR domain[RFC8402]. 68 As defined in [RFC8754], all inter-domain packets are encapsulated 69 for the part of the packet journey that is within the SR domain. The 70 outer IPv6 header is originated by a node of the SR domain and is 71 destined to a node of the SR domain. 73 This document describes a stateless encoding of slice identification 74 in the outer IPv6 header of an SR domain. The slice identification 75 is independent of topology and the QoS/DiffServ policy of the 76 network, thus enabling scalable network slicing for SRv6 overlays. 78 2. Slice Identifier 80 Each network slice in an SR domain is uniquely identified by an 8-bit 81 Slice Identifier (SLID). 83 3. Ingress PE SLID Assignment 85 When an ingress PE receives a packet that traverses the SR domain, it 86 encapsulates the packet in an outer IPv6 header and optional SRH as 87 defined in [RFC8754]. The ingress PE MAY also classify the packet 88 into a slice and set the slice identifier as follows: 90 o Set the SPI bit (SLID Presence Indicator) in the Traffic Class 91 field of the outer IPv6 header. 93 o Write this SLID in the 8 most significant bits of the Flow Label 94 field of the outer IPv6 header. The remaining 12 bits of the Flow 95 Label field were set as described in section 5.5 of [RFC8754] for 96 inter-domain packets. 98 The slice classification method is outside the scope of this 99 document. 101 The choice of the SPI bit from within the IPv6 Traffic Class field is 102 a domain-wide configuration and is outside the scope of this 103 document. 105 4. Per-Slice Forwarding 107 Any router within the SR domain that forwards a packet with SPI bit 108 set uses the SLID to select a slice and apply per-slice policies. 110 There are many different policies that could define a slice for a 111 particular application or service. The most basic of these is 112 bandwidth-allocation, an implementation complying with this 113 specification SHOULD support the bandwidth-allocation slice as 114 defined in the next section. 116 5. Bandwidth-Allocation Slice 118 A per-slice policy is configured at each interface of each router in 119 the SR domain, with one traffic shaper per SLID. The bitrate of each 120 shaper is configured to reflect the bandwidth allocation of the per- 121 slice policy. 123 If shapers are not available, or desirable, an implementation MAY 124 configure one scheduling queue per SLID with a guaranteed bandwidth 125 equal to the bandwidth-allocation for the slice. This option allows 126 a slice to consume more bandwidth than its allocation when available. 128 Per-slice shapers or queues effectively provides a virtual port per 129 slice. This solution MAY be complemented with a per-virtual-port 130 hierarchical DiffServ policy. Within the context of one specific 131 slice, packets are further classified into children DiffServ queues 132 which hang from the virtual port. The DSCP value in the IPv6 header 133 SHOULD be used for queue selection. 135 6. Backward Compatibility 137 The Flow Label usage described in this document is consistent with 138 [RFC6437] and [RFC6438]. 140 PE routers that do not set the SPI bit do not enable the SLID 141 semantic of the Flow Label bits. Hence, SLID-aware routers would not 142 attempt to classify these packets into a slice. 144 Any router that does not process the SPI nor the SLID forwards 145 packets as usual. 147 7. Acknowledgements 149 The authors would like to thank Darren Dukes, Ketan Talaulikar, Jisu 150 Bhattacharya, John Bettink, and Aman Manot for their insightful 151 feedback on this document. 153 8. References 155 8.1. Normative References 157 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 158 Decraene, B., Litkowski, S., and R. Shakir, "Segment 159 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 160 July 2018, . 162 [RFC8754] Filsfils, C., Ed., Dukes, D., Ed., Previdi, S., Leddy, J., 163 Matsushima, S., and D. Voyer, "IPv6 Segment Routing Header 164 (SRH)", RFC 8754, DOI 10.17487/RFC8754, March 2020, 165 . 167 [RFC8986] Filsfils, C., Ed., Camarillo, P., Ed., Leddy, J., Voyer, 168 D., Matsushima, S., and Z. Li, "Segment Routing over IPv6 169 (SRv6) Network Programming", RFC 8986, 170 DOI 10.17487/RFC8986, February 2021, 171 . 173 8.2. Informative References 175 [RFC6437] Amante, S., Carpenter, B., Jiang, S., and J. Rajahalme, 176 "IPv6 Flow Label Specification", RFC 6437, 177 DOI 10.17487/RFC6437, November 2011, 178 . 180 [RFC6438] Carpenter, B. and S. Amante, "Using the IPv6 Flow Label 181 for Equal Cost Multipath Routing and Link Aggregation in 182 Tunnels", RFC 6438, DOI 10.17487/RFC6438, November 2011, 183 . 185 Authors' Addresses 187 Clarence Filsfils (editor) 188 Cisco Systems, Inc. 189 Belgium 191 Email: cf@cisco.com 192 Francois Clad (editor) 193 Cisco Systems, Inc. 194 France 196 Email: fclad@cisco.com 198 Pablo Camarillo 199 Cisco Systems, Inc. 200 Spain 202 Email: pcamaril@cisco.com 204 Kamran Raza 205 Cisco Systems, Inc. 206 Canada 208 Email: skraza@cisco.com