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Checking references for intended status: Proposed Standard ---------------------------------------------------------------------------- (See RFCs 3967 and 4897 for information about using normative references to lower-maturity documents in RFCs) ** Obsolete normative reference: RFC 4970 (Obsoleted by RFC 7770) == Outdated reference: A later version (-27) exists of draft-ietf-ospf-segment-routing-extensions-02 == Outdated reference: A later version (-03) exists of draft-kini-mpls-spring-entropy-label-01 Summary: 1 error (**), 0 flaws (~~), 3 warnings (==), 1 comment (--). Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 Network Working Group X. Xu 3 Internet-Draft Huawei 4 Intended status: Standards Track S. Kini 5 Expires: April 13, 2015 Ericsson 6 S. Sivabalan 7 C. Filsfils 8 Cisco 9 S. Litkowski 10 Orange 11 October 10, 2014 13 Signaling Entropy Label Capability Using OSPF 14 draft-xu-ospf-mpls-elc-01 16 Abstract 18 Multi Protocol Label Switching (MPLS) has defined a mechanism to load 19 balance traffic flows using Entropy Labels (EL). An ingress LSR 20 cannot insert ELs for packets going into a given tunnel unless an 21 egress LSR has indicated via signaling that it can process ELs on 22 that tunnel. This draft defines a mechanism to signal that 23 capability using OSPF. This mechanism is useful when the label 24 advertisement is also done via OSPF. 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 13, 2015. 43 Copyright Notice 45 Copyright (c) 2014 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 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 3 62 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 63 3. Advertising ELC Using OSPF . . . . . . . . . . . . . . . . . 3 64 4. Advertising RLSDC Using OSPF . . . . . . . . . . . . . . . . 3 65 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3 66 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 67 7. Security Considerations . . . . . . . . . . . . . . . . . . . 4 68 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 4 69 8.1. Normative References . . . . . . . . . . . . . . . . . . 4 70 8.2. Informative References . . . . . . . . . . . . . . . . . 4 71 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 5 73 1. Introduction 75 Multi Protocol Label Switching (MPLS) has defined a method in 76 [RFC6790] to load balance traffic flows using Entropy Labels (EL). 77 An ingress LSR cannot insert ELs for packets going into a given 78 tunnel unless an egress LSR has indicated that it can process ELs on 79 that tunnel. [RFC6790] defines the signaling of this capability 80 (a.k.a Entropy Label Capability - ELC) via signaling protocols. 81 Recently, mechanisms are being defined to signal labels via link 82 state Interior Gateway Protocols (IGP) such as OSPF 83 [I-D.ietf-ospf-segment-routing-extensions] . In such scenario the 84 signaling mechanisms defined in [RFC6790] are inadequate. This draft 85 defines a mechanism to signal the ELC using OSPF. This mechanism is 86 useful when the label advertisement is also done via OSPF. In 87 addition, in the cases where stacked LSPs are used for whatever 88 reasons (e.g., SPRING-MPLS [I-D.gredler-spring-mpls] 89 [I-D.filsfils-spring-segment-routing-mpls]), it would be useful for 90 ingress LSRs to know each LSR's capability of reading the maximum 91 label stack deepth. This capability, referred to as Readable Label 92 Stack Deepth Capability (RLSDC) can be used by ingress LSRs to 93 determine whether it's necessary to insert an EL for a given LSP 94 tunnel in the case where there has already been at least one EL in 95 the label stack [I-D.kini-mpls-spring-entropy-label] . Of course, 96 even it has been determined that it's neccessary to insert an EL for 97 a given LSP tunnel, if the egress LSR of that LSP tunnel has not yet 98 indicated that it can process ELs for that tunnel, the ingress LSR 99 MUST NOT include an entropy label for that tunnel as well. 101 1.1. Requirements Language 103 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 104 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 105 document are to be interpreted as described in RFC 2119 [RFC2119]. 107 2. Terminology 109 This memo makes use of the terms defined in [RFC6790] and [RFC4970]. 111 3. Advertising ELC Using OSPF 113 The OSPF Router Information (RI) Opaque LSA defined in [RFC4970] is 114 used by OSPF routers to announce their capabilities. A new TLV 115 within the body of this LSA, called ELC TLV is defined to advertise 116 the capability of the router to process the ELs. It is formatted as 117 described in Section 2.1 of [RFC4970]. This TLV is applicable to 118 both OSPFv2 and OSPFv3. The Type for the ELC TLV needs to be 119 assigned by IANA and it has a Length of zero. The scope of the 120 advertisement depends on the application but it is recommended that 121 it SHOULD be AS-scoped. 123 4. Advertising RLSDC Using OSPF 125 A new TLV within the body of the OSPF RI LSA, called RLSDC TLV is 126 defined to advertise the capability of the router to read the maximum 127 label stack depth. It is formatted as described in Section 2.1 of 128 [RFC4970] with a Type code to be assigned by IANA and a Length of 129 one. The Value field is set to the maximum readable label stack 130 deepth in the range between 1 to 255. The scope of the advertisement 131 depends on the application but it is RECOMMENDED that it SHOULD be 132 domain-wide. If a router has multiple linecards with different 133 capabilities of reading the maximum label stack deepth, the router 134 MUST advertise the smallest one in the RLSDC TLV. This TLV is 135 applicable to both OSPFv2 and OSPFv3. 137 5. Acknowledgements 139 The authors would like to thank Yimin Shen and George Swallow for 140 their comments. 142 6. IANA Considerations 144 This memo includes a request to IANA to allocate two TLV types from 145 the OSPF RI TLVs registry. 147 7. Security Considerations 149 This document does not introduce any new security risk. 151 8. References 153 8.1. Normative References 155 [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate 156 Requirement Levels", BCP 14, RFC 2119, March 1997. 158 [RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S. 159 Shaffer, "Extensions to OSPF for Advertising Optional 160 Router Capabilities", RFC 4970, July 2007. 162 8.2. Informative References 164 [I-D.filsfils-spring-segment-routing-mpls] 165 Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., 166 Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R., 167 Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe, 168 "Segment Routing with MPLS data plane", draft-filsfils- 169 spring-segment-routing-mpls-03 (work in progress), August 170 2014. 172 [I-D.gredler-spring-mpls] 173 Gredler, H., Rekhter, Y., Jalil, L., Kini, S., and X. Xu, 174 "Supporting Source/Explicitly Routed Tunnels via Stacked 175 LSPs", draft-gredler-spring-mpls-06 (work in progress), 176 May 2014. 178 [I-D.ietf-ospf-segment-routing-extensions] 179 Psenak, P., Previdi, S., Filsfils, C., Gredler, H., 180 Shakir, R., Henderickx, W., and J. Tantsura, "OSPF 181 Extensions for Segment Routing", draft-ietf-ospf-segment- 182 routing-extensions-02 (work in progress), August 2014. 184 [I-D.kini-mpls-spring-entropy-label] 185 Kini, S., Kompella, K., Sivabalan, S., Litkowski, S., 186 Shakir, R., Xu, X., Henderickx, W., and J. Tantsura, 187 "Entropy labels for source routed stacked tunnels", draft- 188 kini-mpls-spring-entropy-label-01 (work in progress), 189 September 2014. 191 [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and 192 L. Yong, "The Use of Entropy Labels in MPLS Forwarding", 193 RFC 6790, November 2012. 195 Authors' Addresses 197 Xiaohu Xu 198 Huawei 200 Email: xuxiaohu@huawei.com 202 Sriganesh Kini 203 Ericsson 205 Email: sriganesh.kini@ericsson.com 207 Siva Sivabalan 208 Cisco 210 Email: msiva@cisco.com 212 Clarence Filsfils 213 Cisco 215 Email: cfilsfil@cisco.com 217 Stephane Litkowski 218 Orange 220 Email: stephane.litkowski@orange.com