Network Working Group X. Xu Internet-Draft Huawei Intended status: Standards Track S. Kini Expires: March 10, 2014 Ericsson S. Sivabalan C. Filsfils Cisco September 06, 2013 Signaling Entropy Label Capability Using Interior Gateway Protocols draft-xu-mpls-el-capability-signaling-igp-00 Abstract Multi Protocol Label Switching (MPLS) has defined a mechanism to load balance traffic flows using Entropy Labels (EL). An LSR inserts the EL Indicator and the EL label only if the LSR that pops them has the capability of processing them. This draft defines a mechanism to signal that capability using link state Interior Gateway Protocols (IGP). This mechanism is useful when the label advertisement is also done via that IGP. Status of This Memo This Internet-Draft is submitted in full conformance with the provisions of BCP 78 and BCP 79. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at http://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." This Internet-Draft will expire on March 10, 2014. Copyright Notice Copyright (c) 2013 IETF Trust and the persons identified as the document authors. All rights reserved. This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of Xu, et al. Expires March 10, 2014 [Page 1] Internet-Draft Signaling for EL Capability Using IGPs September 2013 publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 1.1. Requirements Language . . . . . . . . . . . . . . . . . . 2 2. Abbreviations and Terminology . . . . . . . . . . . . . . . . 3 3. Advertising ELC using OSPF . . . . . . . . . . . . . . . . . 3 4. Advertising ELC using ISIS . . . . . . . . . . . . . . . . . 3 5. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 3 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 3 7. Security Considerations . . . . . . . . . . . . . . . . . . . 3 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 3 8.1. Normative References . . . . . . . . . . . . . . . . . . 4 8.2. Informative References . . . . . . . . . . . . . . . . . 4 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction Multi Protocol Label Switching (MPLS) has defined a method in [RFC6790] to load balance traffic flows using Entropy Labels (EL). An LSR inserts the EL Indicator and the EL only if the LSR that pops those labels has the capability of recognizing and processing them. [RFC6790] defines the signaling of this capability (a.k.a Entropy Label Capability - ELC) via signaling protocols. Recently, mechanisms are being defined to signal labels via link state Interior Gateway Protocols (IGP) such as OSPF [I-D.psenak-ospf-segment-routing-extensions] and ISIS [I-D.previdi-isis-segment-routing-extensions]. In such scenarios the signaling mechanisms defined in [RFC6790] are inadequate. This draft defines mechanisms to signal the ELC using the link state advertisements (LSA) of the IGPs OSPF and ISIS. These capabilities are advertised for the entire router and not just a single prefix. This mechanism is useful when the label advertisement is also done via that IGP. 1.1. Requirements Language The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119]. Xu, et al. Expires March 10, 2014 [Page 2] Internet-Draft Signaling for EL Capability Using IGPs September 2013 2. Abbreviations and Terminology This memo makes use of the terms defined in [RFC6790], [RFC4970] and [RFC4971]. 3. Advertising ELC using OSPF The OSPF Router Information (RI) Opaque LSA defined in [RFC4970] is used by OSPF routers to announce their capabilities. A new TLV within the body of this LSA, called ELC TLV is defined to advertise the capability of the router to process the ELI and EL. Its formatting follows that described in sec 2.1 of [RFC4970]. This TLV is applicable to both OSPFv2 and OSPFv3. The Type for the ELC TLV needs to be assigned by IANA and it has a Length of zero. The scope of the advertisement depends on the application but it is recommended that it SHOULD be AS-scoped. 4. Advertising ELC using ISIS The IS-IS Router CAPABILITY TLV defined in [RFC4971] is used by IS-IS routers to announce their capabilities. A new sub-TLV of this TLV, called ELC sub-TLV is defined to advertise the capability of the router to process the ELI and EL. It is formatted as described in [RFC5305] with a Type code to be assigned by IANA and a Length of zero. The scope of the advertisement depends on the application but it is recommended that it SHOULD be domain-wide. 5. Acknowledgements The authors would like to thank TBD for their comments. 6. IANA Considerations This memo includes requests to IANA to allocate a TLV type from the OSPF RI TLVs registry and a sub-TLV type within the IS-IS Router Capability TLV. 7. Security Considerations This document does not introduce any new security considerations. 8. References Xu, et al. Expires March 10, 2014 [Page 3] Internet-Draft Signaling for EL Capability Using IGPs September 2013 8.1. Normative References [I-D.previdi-isis-segment-routing-extensions] Previdi, S., Filsfils, C., Bashandy, A., Gredler, H., and S. Litkowski, "IS-IS Extensions for Segment Routing", draft-previdi-isis-segment-routing-extensions-02 (work in progress), July 2013. [I-D.psenak-ospf-segment-routing-extensions] Psenak, P., Previdi, S., Filsfils, C., Gredler, H., and R. Shakir, "OSPF Extensions for Segment Routing", draft- psenak-ospf-segment-routing-extensions-02 (work in progress), July 2013. [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, March 1997. [RFC4970] Lindem, A., Shen, N., Vasseur, JP., Aggarwal, R., and S. Shaffer, "Extensions to OSPF for Advertising Optional Router Capabilities", RFC 4970, July 2007. [RFC4971] Vasseur, JP., Shen, N., and R. Aggarwal, "Intermediate System to Intermediate System (IS-IS) Extensions for Advertising Router Information", RFC 4971, July 2007. [RFC5305] Li, T. and H. Smit, "IS-IS Extensions for Traffic Engineering", RFC 5305, October 2008. [RFC6790] Kompella, K., Drake, J., Amante, S., Henderickx, W., and L. Yong, "The Use of Entropy Labels in MPLS Forwarding", RFC 6790, November 2012. 8.2. Informative References [I-D.filsfils-rtgwg-segment-routing] Filsfils, C., Previdi, S., Bashandy, A., Decraene, B., Litkowski, S., Horneffer, M., Milojevic, I., Shakir, R., Ytti, S., Henderickx, W., Tantsura, J., and E. Crabbe, "Segment Routing Architecture", draft-filsfils-rtgwg- segment-routing-00 (work in progress), June 2013. Authors' Addresses Xiaohu Xu Huawei Email: xuxiaohu@huawei.com Xu, et al. Expires March 10, 2014 [Page 4] Internet-Draft Signaling for EL Capability Using IGPs September 2013 Sriganesh Kini Ericsson Email: sriganesh.kini@ericsson.com Siva Sivabalan Cisco Email: msiva@cisco.com Clarence Filsfils Cisco Email: cfilsfil@cisco.com Xu, et al. Expires March 10, 2014 [Page 5]