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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-07) exists of draft-ietf-mpls-flow-ident-04 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 MPLS Working Group S. Bryant 3 Internet-Draft M. Chen 4 Intended status: Informational Z. Li 5 Expires: December 28, 2017 Huawei 6 G. Swallow 7 S. Sivabalan 8 Cisco Systems 9 G. Mirsky 10 Ericsson 11 June 26, 2017 13 Synonymous Flow Label Framework 14 draft-bryant-mpls-sfl-framework-05 16 Abstract 18 draft-ietf-mpls-flow-ident describes the requirement for introducing 19 flow identities within the MPLS architecture. This document 20 describes a method of accomplishing this by using a technique called 21 Synonymous Flow Labels in which labels which mimic the behaviour of 22 other labels provide the identification service. These identifiers 23 can be used to trigger per-flow operations on the on the packet at 24 the receiving label switching router. 26 Status of This Memo 28 This Internet-Draft is submitted in full conformance with the 29 provisions of BCP 78 and BCP 79. 31 Internet-Drafts are working documents of the Internet Engineering 32 Task Force (IETF). Note that other groups may also distribute 33 working documents as Internet-Drafts. The list of current Internet- 34 Drafts is at http://datatracker.ietf.org/drafts/current/. 36 Internet-Drafts are draft documents valid for a maximum of six months 37 and may be updated, replaced, or obsoleted by other documents at any 38 time. It is inappropriate to use Internet-Drafts as reference 39 material or to cite them other than as "work in progress." 41 This Internet-Draft will expire on December 28, 2017. 43 Copyright Notice 45 Copyright (c) 2017 IETF Trust and the persons identified as the 46 document authors. All rights reserved. 48 This document is subject to BCP 78 and the IETF Trust's Legal 49 Provisions Relating to IETF Documents 50 (http://trustee.ietf.org/license-info) in effect on the date of 51 publication of this document. Please review these documents 52 carefully, as they describe your rights and restrictions with respect 53 to this document. Code Components extracted from this document must 54 include Simplified BSD License text as described in Section 4.e of 55 the Trust Legal Provisions and are provided without warranty as 56 described in the Simplified BSD License. 58 Table of Contents 60 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 61 2. Requirements Language . . . . . . . . . . . . . . . . . . . . 2 62 3. Synonymous Flow Labels . . . . . . . . . . . . . . . . . . . 3 63 4. User Service Traffic in the Data Plane . . . . . . . . . . . 4 64 4.1. Applications Label Present . . . . . . . . . . . . . . . 4 65 4.1.1. Setting TTL and the Traffic Class Bits . . . . . . . 5 66 4.2. Single Label Stack . . . . . . . . . . . . . . . . . . . 5 67 4.2.1. Setting TTL and the Traffic Class Bits . . . . . . . 6 68 4.3. Aggregation of SFL Actions . . . . . . . . . . . . . . . 6 69 5. Equal Cost Multipath Considerations . . . . . . . . . . . . . 7 70 6. Privacy Considerations . . . . . . . . . . . . . . . . . . . 8 71 7. Security Considerations . . . . . . . . . . . . . . . . . . . 8 72 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 73 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 74 9.1. Normative References . . . . . . . . . . . . . . . . . . 8 75 9.2. Informative References . . . . . . . . . . . . . . . . . 9 76 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 78 1. Introduction 80 [I-D.ietf-mpls-flow-ident] describes the requirement for introducing 81 flow identities within the MPLS architecture. 83 This document describes a method of accomplishing this by using a 84 technique called Synonymous Flow Labels (SFL) (see (Section 2)) in 85 which labels which mimic the behaviour of other labels provide the 86 identification service. These identifiers can be used to trigger 87 per-flow operations on the packet at the receiving label switching 88 router. 90 2. Requirements Language 92 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 93 "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and 94 "OPTIONAL" in this document are to be interpreted as described in BCP 95 14 [RFC2119] [RFC8174] when, and only when, they appear in all 96 capitals, as shown here. 98 3. Synonymous Flow Labels 100 An SFL is defined to be a label that causes exactly the same 101 behaviour at the egress Label Switching Router (LSR) as the label it 102 replaces, but in addition also causes an agreed action to take place 103 on the packet. There are many possible additional actions such as 104 the measurement of the number of received packets in a flow, 105 triggering IPFIX inspection, triggering other types of Deep Packet 106 Inspection, or identification of the packet source. In, for example, 107 a Performance Monitoring (PM) application, the agreed action could be 108 the recording of the receipt of the packet by incrementing a packet 109 counter. This is a natural action in many MPLS implementations, and 110 where supported this permits the implementation of high quality 111 packet loss measurement without any change to the packet forwarding 112 system. 114 Consider an MPLS application such as a pseudowire (PW), and consider 115 that it is desired to use the approach specified in this document to 116 make a packet loss measurement. By some method outside the scope of 117 this text, two labels, synonymous with the PW labels are obtained 118 from the egress terminating provider edge (T-PE). By alternating 119 between these SFLs and using them in place of the PW label, the PW 120 packets may be batched for counting without any impact on the PW 121 forwarding behaviour (note that strictly only one SFL is needed in 122 this application, but that is an optimization that is a matter for 123 the implementor). 125 Now consider an MPLS application that is multi-point to point such as 126 a VPN. Here it is necessary to identify a packet batch from a 127 specific source. This is achieved by making the SFLs source 128 specific, so that batches from one source are marked differently from 129 batches from another source. The sources all operate independently 130 and asynchronously from each other, independently co-ordinating with 131 the destination. Each ingress is thus able to establish its own SFL 132 to identify the sub-flow and thus enable PM per flow. 134 Finally we need to consider the case where there is no MPLS 135 application label such as occurs when sending IP over an LSP. In 136 this case introducing an SFL that was synonymous with the LSP label 137 would introduce network wide forwarding state. This would not be 138 acceptable for scaling reasons. We therefore have no choice but to 139 introduce an additional label. Where penultimate hop popping (PHP) 140 is in use, the semantics of this additional label can be similar to 141 the LSP label. Where PHP is not in use, the semantics are similar to 142 an MPLS explicit NULL. In both of these cases the label has the 143 additional semantics of the SFL. 145 Note that to achieve the goals set out in Section 1 SFLs need to be 146 allocated from the platform label table. 148 4. User Service Traffic in the Data Plane 150 As noted in Section 3 it is necessary to consider two cases: 152 1. Applications label present 154 2. Single label stack 156 4.1. Applications Label Present 158 Figure 1 shows the case in which both an LSP label and an application 159 label are present in the MPLS label stack. Traffic with no SFL 160 function present runs over the "normal" stack, and SFL enabled flows 161 run over the SFL stack with the SFL used to indicate the packet 162 batch. 164 +-----------------+ +-----------------+ 165 | | | | 166 | LSP | | LSP | . 352 [RFC5462] Andersson, L. and R. Asati, "Multiprotocol Label Switching 353 (MPLS) Label Stack Entry: "EXP" Field Renamed to "Traffic 354 Class" Field", RFC 5462, DOI 10.17487/RFC5462, February 355 2009, . 357 [RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC 358 2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174, 359 May 2017, . 361 9.2. Informative References 363 [I-D.ietf-mpls-flow-ident] 364 Bryant, S., Pignataro, C., Chen, M., Li, Z., and G. 365 Mirsky, "MPLS Flow Identification Considerations", draft- 366 ietf-mpls-flow-ident-04 (work in progress), February 2017. 368 [RFC6374] Frost, D. and S. Bryant, "Packet Loss and Delay 369 Measurement for MPLS Networks", RFC 6374, 370 DOI 10.17487/RFC6374, September 2011, 371 . 373 [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and 374 L. Yong, "The Use of Entropy Labels in MPLS Forwarding", 375 RFC 6790, DOI 10.17487/RFC6790, November 2012, 376 . 378 [RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an 379 Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May 380 2014, . 382 Authors' Addresses 384 Stewart Bryant 385 Huawei 387 Email: stewart.bryant@gmail.com 389 Mach Chen 390 Huawei 392 Email: mach.chen@huawei.com 394 Zhenbin Li 395 Huawei 397 Email: lizhenbin@huawei.com 398 George Swallow 399 Cisco Systems 401 Email: swallow@cisco.com 403 Siva Sivabalan 404 Cisco Systems 406 Email: msiva@cisco.com 408 Gregory Mirsky 409 Ericsson 411 Email: gregory.mirsky@eicsson.com