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Checking references for intended status: Informational ---------------------------------------------------------------------------- == Outdated reference: A later version (-03) exists of draft-bryant-mpls-flow-ident-02 Summary: 0 errors (**), 0 flaws (~~), 2 warnings (==), 1 comment (--).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 S. Bryant 3 Internet-Draft G. Swallow 4 Intended status: Informational S. Sivabalan 5 Expires: April 20, 2016 Cisco Systems 6 G. Mirsky 7 Ericsson 8 M. Chen 9 Z. Li 10 Huawei 11 October 18, 2015 13 Synonymous Flow Label Framework 14 draft-bryant-mpls-sfl-framework-00 16 Abstract 18 draft-bryant-mpls-flow-ident describes the requirement for 19 introducing flow identities within the MPLS architecture. This 20 document describes a method of accomplishing this by using a 21 technique called Synonymous Flow Labels in which labels which mimic 22 the behaviour of other labels provide the identification service. 23 These identifiers can be used to trigger per-flow operations on the 24 on the packet at 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 April 20, 2016. 43 Copyright Notice 45 Copyright (c) 2015 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. Synonymous Flow Labels . . . . . . . . . . . . . . . . . . . 2 62 3. User Service Traffic in the Data Plane . . . . . . . . . . . 4 63 3.1. Applications Label Present . . . . . . . . . . . . . . . 4 64 3.1.1. Setting TTL and the Traffic Class Bits . . . . . . . 4 65 3.2. Single Label Stack . . . . . . . . . . . . . . . . . . . 5 66 3.2.1. Setting TTL and the Traffic Class Bits . . . . . . . 6 67 3.3. Aggregation of SFL Actions . . . . . . . . . . . . . . . 6 68 4. Equal Cost Multipath Considerations . . . . . . . . . . . . . 7 69 5. Privacy Considerations . . . . . . . . . . . . . . . . . . . 8 70 6. Security Considerations . . . . . . . . . . . . . . . . . . . 8 71 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 8 72 8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 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.bryant-mpls-flow-ident] describes the requirement for 81 introducing 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. Synonymous Flow Labels 92 An SFL is defined to be a label that causes exactly the same 93 behaviour at the egress Label Switching Router (LSR) as the label it 94 replaces, but in addition also causes an agreed action to take place 95 on the packet. There are many possible additional actions such as 96 the measurement of the number of received packets in a flow, 97 triggering IPFIX inspection, triggering other types of Deep Packet 98 Inspection, or identification of the packet source. In, for example, 99 a Performance Monitoring (PM) application, the agreed action could be 100 the recording of the receipt of the packet by incrementing a packet 101 counter. This is a natural action in many MPLS implementations, and 102 where supported this permits the implementation of high quality 103 packet loss measurement without any change to the packet forwarding 104 system. 106 Consider an MPLS application such as a pseudowire (PW), and consider 107 that it is desired to use the approach specified in this document to 108 make a packet loss measurement. By some method outside the scope of 109 this text, two labels, synonymous with the PW labels are obtained 110 from the egress terminating provider edge (T-PE). By alternating 111 between these SFLs and using them in place of the PW label, the PW 112 packets may be batched for counting without any impact on the PW 113 forwarding behaviour (note that strictly only one SFL is needed in 114 this application, but that is an optimization that is a matter for 115 the implementor). 117 Now consider an MPLS application that is multi-point to point such as 118 a VPN. Here it is necessary to identify a packet batch from a 119 specific source. This is achieved by making the SFLs source 120 specific, so that batches from one source are marked differently from 121 batches from another source. The sources all operate independently 122 and asynchronously from each other, independently co-ordinating with 123 the destination. Each ingress is thus able to establish its own SFL 124 to identify the sub-flow and thus enable PM per flow. 126 Finally we need to consider the case where there is no MPLS 127 application label such as occurs when sending IP over an LSP. In 128 this case introducing an SFL that was synonymous with the LSP label 129 would introduce network wide forwarding state. This would not be 130 acceptable for scaling reasons. We therefore have no choice but to 131 introduce an additional label. Where penultimate hop popping (PHP) 132 is in use, the semantics of this additional label can be similar to 133 the LSP label. Where PHP is not in use, the semantics are similar to 134 an MPLS explicit NULL. In both of these cases the label has the 135 additional semantics of the SFL. 137 Note that to achieve the goals set out in Section 1 SFLs need to be 138 allocated from the platform label table. 140 3. User Service Traffic in the Data Plane 142 As noted in Section 2 it is necessary to consider two cases: 144 1. Applications label present 146 2. Single label stack 148 3.1. Applications Label Present 150 Figure 1 shows the case in which both an LSP label and an application 151 label are present in the MPLS label stack. Traffic with no SFL 152 function present runs over the "normal" stack, and SFL enabled flows 153 run over the SFL stack with the SFL used to indicate the packet 154 batch. 156 +-----------------+ +-----------------+ 157 | | | | 158 | LSP | | LSP | . 347 9.2. Informative References 349 [I-D.bryant-mpls-flow-ident] 350 Bryant, S., Pignataro, C., Chen, M., Li, Z., and G. 351 Mirsky, "MPLS Flow Identification", draft-bryant-mpls- 352 flow-ident-02 (work in progress), September 2015. 354 [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and 355 L. Yong, "The Use of Entropy Labels in MPLS Forwarding", 356 RFC 6790, DOI 10.17487/RFC6790, November 2012, 357 . 359 [RFC7258] Farrell, S. and H. Tschofenig, "Pervasive Monitoring Is an 360 Attack", BCP 188, RFC 7258, DOI 10.17487/RFC7258, May 361 2014, . 363 Authors' Addresses 365 Stewart Bryant 366 Cisco Systems 368 Email: stbryant@cisco.com 370 George Swallow 371 Cisco Systems 373 Email: swallow@cisco.com 375 Siva Sivabalan 376 Cisco Systems 378 Email: msiva@cisco.com 380 Greg Mirsky 381 Ericsson 383 Email: gregory.mirsky@ericsson.com 385 Mach(Guoyi) Chen 386 Huawei 388 Email: mach.chen@huawei.com 389 Zhenbin(Robin) Li 390 Huawei 392 Email: lizhenbin@huawei.com