idnits 2.17.1 draft-decraene-mpls-slid-encoded-entropy-label-id-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 an IANA Considerations section. (See Section 2.2 of https://www.ietf.org/id-info/checklist for how to handle the case when there are no actions for IANA.) ** 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 141: '...ne of those buts MUST allow the choice...' RFC 2119 keyword, line 168: '...ncoding the SLID MUST be configurable ...' RFC 2119 keyword, line 177: '... bit set MUST use the SLID to select...' RFC 2119 keyword, line 183: '... specification SHOULD support the ba...' RFC 2119 keyword, line 193: '...e, or desirable, an implementation MAY...' (2 more instances...) -- The draft header indicates that this document updates RFC6790, but the abstract doesn't seem to mention this, which it should. Miscellaneous warnings: ---------------------------------------------------------------------------- == The copyright year in the IETF Trust and authors Copyright Line does not match the current year -- The document date (February 22, 2021) is 1159 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(See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) == Outdated reference: A later version (-09) exists of draft-filsfils-spring-srv6-stateless-slice-id-02 -- Obsolete informational reference (is this intentional?): RFC 8321 (Obsoleted by RFC 9341) Summary: 3 errors (**), 0 flaws (~~), 2 warnings (==), 3 comments (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MPLS B. Decraene, Ed. 3 Internet-Draft Orange 4 Updates: 6790 (if approved) C. Filsfils 5 Intended status: Standards Track Cisco Systems, Inc. 6 Expires: August 26, 2021 W. Henderickx 7 Nokia 8 T. Saad 9 V. Beeram 10 Juniper Networks 11 L. Jalil 12 Verizon 13 February 22, 2021 15 Using Entropy Label for Network Slice Identification in MPLS networks. 16 draft-decraene-mpls-slid-encoded-entropy-label-id-01 18 Abstract 20 This document defines a solution to encode a slice identifier in MPLS 21 in order to distinguish packets that belong to different slices, to 22 allow enforcing per network slice policies (.e.g, Qos). 24 The slice identification is independent of the topology. It allows 25 for QoS/DiffServ policy on a per slice basis in addition to the per 26 packet QoS/DiffServ policy provided by the MPLS Traffic Class field. 28 In order to minimize the size of the MPLS stack and to ease 29 incremental deployment the slice identifier is encoded as part of the 30 Entropy Label. 32 This document also extends the use of the TTL field of the Entropy 33 Label in order to provide a flexible set of flags called the Entropy 34 Label Control field. 36 Status of This Memo 38 This Internet-Draft is submitted in full conformance with the 39 provisions of BCP 78 and BCP 79. 41 Internet-Drafts are working documents of the Internet Engineering 42 Task Force (IETF). Note that other groups may also distribute 43 working documents as Internet-Drafts. The list of current Internet- 44 Drafts is at https://datatracker.ietf.org/drafts/current/. 46 Internet-Drafts are draft documents valid for a maximum of six months 47 and may be updated, replaced, or obsoleted by other documents at any 48 time. It is inappropriate to use Internet-Drafts as reference 49 material or to cite them other than as "work in progress." 51 This Internet-Draft will expire on August 26, 2021. 53 Copyright Notice 55 Copyright (c) 2021 IETF Trust and the persons identified as the 56 document authors. All rights reserved. 58 This document is subject to BCP 78 and the IETF Trust's Legal 59 Provisions Relating to IETF Documents 60 (https://trustee.ietf.org/license-info) in effect on the date of 61 publication of this document. Please review these documents 62 carefully, as they describe your rights and restrictions with respect 63 to this document. Code Components extracted from this document must 64 include Simplified BSD License text as described in Section 4.e of 65 the Trust Legal Provisions and are provided without warranty as 66 described in the Simplified BSD License. 68 Table of Contents 70 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 71 2. Entropy Label Control field . . . . . . . . . . . . . . . . . 3 72 3. Slice Identifier . . . . . . . . . . . . . . . . . . . . . . 4 73 3.1. Ingress LSR . . . . . . . . . . . . . . . . . . . . . . . 4 74 3.2. Transit LSR . . . . . . . . . . . . . . . . . . . . . . . 4 75 3.3. Bandwidth-Allocation Slice . . . . . . . . . . . . . . . 4 76 3.4. Backward Compatibility . . . . . . . . . . . . . . . . . 5 77 3.5. Benefits . . . . . . . . . . . . . . . . . . . . . . . . 5 78 4. End to end absolute loss measurements . . . . . . . . . . . . 6 79 5. Programmed sampling of packets . . . . . . . . . . . . . . . 6 80 6. Changes / Authors Notes . . . . . . . . . . . . . . . . . . . 6 81 7. References . . . . . . . . . . . . . . . . . . . . . . . . . 6 82 7.1. Normative References . . . . . . . . . . . . . . . . . . 6 83 7.2. Informative References . . . . . . . . . . . . . . . . . 7 84 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 7 86 1. Introduction 88 Segment Routing (SR) [RFC8402] leverages the source-routing paradigm. 89 A node steers a packet through a controlled set of instructions, 90 called segments, by prepending the packet with an SR header. In the 91 SR-MPLS data plane [RFC8660], the SR header is instantiated through a 92 label stack. 94 This document defines a solution to encode a slice identifier in MPLS 95 in order to provide QoS on a per slice basis. It allows for QoS/ 96 DiffServ policy on a per slice basis in addition to the per packet 97 QoS/DiffServ policy provided by the MPLS Traffic Class field. The 98 slice identification is independent of the topology and the QoS of 99 the network, thus enabling scalable network slicing. 101 This document encodes the slice identifier in a portion of the MPLS 102 Entropy Label (EL) defined in [RFC6790]. This has advantages in SR- 103 MPLS networks as it avoids the use of additional label which would 104 increase the size of the label stack. This also reuses the data 105 plane processing of the Entropy Label on the egress LSR, the 106 signaling of the Entropy Label capability from the egress to the 107 ingress [I-D.ietf-isis-mpls-elc] [I-D.ietf-ospf-mpls-elc], and the 108 signaling capability of transit routers to read this label [RFC8491] 109 which allows for an easier and faster incremental deployment. 111 2. Entropy Label Control field 113 [RFC6790] defines the MPLS Entropy Label. [RFC6790] section 4.2 114 defines the use of the Entropy Label Indicator (ELI) followed by the 115 Entropy Label (EL) and the MPLS header fields (Label, TC, S, TTL) in 116 each. [RFC6790] also specifies that the TTL field of the EL must be 117 set to zero by the ingress LSR. 119 Following the procedures of [RFC6790] EL is never used for forwarding 120 and its TTL is never looked at nor decremented: 122 o An EL capable Egress LSR performs a lookup on the ELI and as a 123 result pop two labels: ELI and EL. 125 o An EL non-capable Egress LSR performs a lookup on the ELI and as a 126 result must drop the packet as specified in [RFC3031] for the 127 handling of an invalid incoming label. 129 Hence essentially the TTL field of the EL behaves as a reserved field 130 which must be set to zero when sent and ignored when received. 132 This documents extends the TTL field of the EL and calls it the 133 Entropy Label Control (ELC) field. The ELC is a set of eight flags: 134 ELC0 for bit 0, ELC1 for bit 1,..., ELC7 for bit 7. 136 Given that the MPLS header is very compact (32 bits) with no reserved 137 bits and that MPLS is used within a trusted administrative domain, 138 the semantic of these bits is not standardized but defined on a per 139 administrative domain basis. This allows for increased re-use and 140 flexibility of this scarce resource. As a consequence, an 141 application using one of those buts MUST allow the choice of the bit 142 by configuration by the network operator. 144 3. Slice Identifier 146 Each network slice in an MPLS domain is uniquely identified by a 147 Slice Identifier (SLID). This section proposes to encode the SLID in 148 a portion of the MPLS Entropy Label defined in [RFC6790]. 150 The number of bits to be used for encoding the SLID in the EL is 151 governed by a local policy and uniform within a network slice policy 152 domain. 154 3.1. Ingress LSR 156 When an ingress LSR classifies that a packet belongs to the slice and 157 that the egress has indicated via signaling that it can process EL 158 for the tunnel, the ingress LSR pushes an Entropy Label with the: 160 o SLID encoded in the most significant bits of the Entropy Label. 162 o the entropy information encoded in the remaining lower bits of the 163 Entropy Label as described in section 4.2 of [RFC6790]. 165 o SPI bit (SLID Presence Indicator) set in one bit of the ELC field. 167 The choice of the ELC field used for SPI, and the number of bits to 168 be used for encoding the SLID MUST be configurable by the network 169 operator. 171 The slice classification method is outside the scope of this 172 document. 174 3.2. Transit LSR 176 Any router within the SR domain that forwards a packet with the SPI 177 bit set MUST use the SLID to select a slice and apply per-slice 178 policies. 180 There are many different policies that could define a slice for a 181 particular application or service. The most basic of these is 182 bandwidth-allocation, an implementation complying with this 183 specification SHOULD support the bandwidth-allocation slice as 184 defined in the next section. 186 3.3. Bandwidth-Allocation Slice 188 A per-slice policy is configured at each interface of each router in 189 the SR domain, with one traffic shaper per SLID. The bit rate of 190 each shaper is configured to reflect the bandwidth allocation of the 191 per-slice policy. 193 If shapers are not available, or desirable, an implementation MAY 194 configure one scheduling queue per SLID with a guaranteed bandwidth 195 equal to the bandwidth-allocation for the slice. This option allows 196 a slice to consume more bandwidth than its allocation when available. 198 Per-slice shapers or queues effectively provides a virtual port per 199 slice. This solution MAY be complemented with a per-virtual-port 200 hierarchical DiffServ policy. Within the context of one specific 201 slice, packets are further classified into children DiffServ queues 202 which hang from the virtual port. The Traffic Class value in the 203 MPLS header SHOULD be used for queue selection. 205 3.4. Backward Compatibility 207 The Entropy Label usage described in this document is consistent with 208 [RFC6790] as ingress LSRs freely chooses the EL of a given flow, and 209 transit LSRs treat the EL as an opaque set of bits. 211 As per [RFC6790] an ingress LSR that does not support this extension 212 has the SPI bit cleared, and thus does not enable the SLID semantic 213 of the Entropy bits. Hence, SLID-aware transit LSRs will not 214 classify these packets into a slice. 216 3.5. Benefits 218 From a Segment Routing architecture perspective, this network slice 219 identifier for SR-MPLS is inline with the network slice identifier 220 for SRv6 proposed in [I-D.filsfils-spring-srv6-stateless-slice-id]. 222 From an SR-MPLS perspective, using the EL to carry the network slice 223 identifier has multiple benefits: 225 o This limits the number of labels pushed on the MPLS stack compared 226 to using a pair of labels (ELI+EL) for flow entropy plus two or 227 three labels for the slice indicator and the slice identifier. 228 This is beneficial for the ingress LSR which may have limitations 229 with regards to the number of labels pushed, for the transit LSR 230 which may have limitations with regards to the label stack depth 231 to be examined during transit in order to read both the entropy 232 and the SLID. This presents additional benefit to network 233 operators by reducing the packet overhead for traffic carried 234 through the network; 236 o This avoids defining new extensions for the signaling of the 237 egress capability to support the slice indicator and the slice 238 identifier; 240 o This improves incremental deployment as all egress LSRs supporting 241 EL can be sent the slice identifier from day one, allowing slice 242 classification on transit LSRs. 244 4. End to end absolute loss measurements 246 This section describes the usage of a ELC flag to enable packet loss 247 measurements, as described in section 3.1 of [RFC8321], for SR-MPLS 248 networks. 250 TBD 252 5. Programmed sampling of packets 254 This section describes the usage of a ELC flag to detect end to end 255 packet loss. 257 TBD 259 6. Changes / Authors Notes 261 [RFC Editor: Please remove this section before publication] 263 00: Initial version. 265 01: New co-author 267 7. References 269 7.1. Normative References 271 [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and 272 L. Yong, "The Use of Entropy Labels in MPLS Forwarding", 273 RFC 6790, DOI 10.17487/RFC6790, November 2012, 274 . 276 [RFC8402] Filsfils, C., Ed., Previdi, S., Ed., Ginsberg, L., 277 Decraene, B., Litkowski, S., and R. Shakir, "Segment 278 Routing Architecture", RFC 8402, DOI 10.17487/RFC8402, 279 July 2018, . 281 [RFC8660] Bashandy, A., Ed., Filsfils, C., Ed., Previdi, S., 282 Decraene, B., Litkowski, S., and R. Shakir, "Segment 283 Routing with the MPLS Data Plane", RFC 8660, 284 DOI 10.17487/RFC8660, December 2019, 285 . 287 7.2. Informative References 289 [I-D.filsfils-spring-srv6-stateless-slice-id] 290 Filsfils, C., Clad, F., Camarillo, P., and K. Raza, 291 "Stateless and Scalable Network Slice Identification for 292 SRv6", draft-filsfils-spring-srv6-stateless-slice-id-02 293 (work in progress), January 2021. 295 [I-D.ietf-isis-mpls-elc] 296 Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S., 297 and M. Bocci, "Signaling Entropy Label Capability and 298 Entropy Readable Label Depth Using IS-IS", draft-ietf- 299 isis-mpls-elc-13 (work in progress), May 2020. 301 [I-D.ietf-ospf-mpls-elc] 302 Xu, X., Kini, S., Psenak, P., Filsfils, C., Litkowski, S., 303 and M. Bocci, "Signaling Entropy Label Capability and 304 Entropy Readable Label Depth Using OSPF", draft-ietf-ospf- 305 mpls-elc-15 (work in progress), June 2020. 307 [RFC3031] Rosen, E., Viswanathan, A., and R. Callon, "Multiprotocol 308 Label Switching Architecture", RFC 3031, 309 DOI 10.17487/RFC3031, January 2001, 310 . 312 [RFC8321] Fioccola, G., Ed., Capello, A., Cociglio, M., Castaldelli, 313 L., Chen, M., Zheng, L., Mirsky, G., and T. Mizrahi, 314 "Alternate-Marking Method for Passive and Hybrid 315 Performance Monitoring", RFC 8321, DOI 10.17487/RFC8321, 316 January 2018, . 318 [RFC8491] Tantsura, J., Chunduri, U., Aldrin, S., and L. Ginsberg, 319 "Signaling Maximum SID Depth (MSD) Using IS-IS", RFC 8491, 320 DOI 10.17487/RFC8491, November 2018, 321 . 323 Authors' Addresses 325 Bruno Decraene (editor) 326 Orange 328 Email: bruno.decraene@orange.com 329 Clarence Filsfils 330 Cisco Systems, Inc. 331 Belgium 333 Email: cf@cisco.com 335 Wim Henderickx 336 Nokia 337 Copernicuslaan 50 338 Antwerp 2018, CA 95134 339 Belgium 341 Email: wim.henderickx@nokia.com 343 Tarek Saad 344 Juniper Networks 346 Email: tsaad@juniper.net 348 Vishnu Pavan Beeram 349 Juniper Networks 351 Email: vbeeram@juniper.net 353 Luay Jalil 354 Verizon 356 Email: luay.jalil@verizon.com