--- 1/draft-ietf-rtgwg-multihomed-prefix-lfa-03.txt 2017-12-01 12:13:12.342500542 -0800 +++ 2/draft-ietf-rtgwg-multihomed-prefix-lfa-04.txt 2017-12-01 12:13:12.378501407 -0800 @@ -1,28 +1,25 @@ Routing Area Working Group P. Sarkar, Ed. Internet-Draft Arrcus, Inc. Updates: 5286 (if approved) S. Hegde -Intended status: Standards Track C. Bowers -Expires: May 3, 2018 Juniper Networks, Inc. - U. Chunduri, Ed. +Intended status: Standards Track Juniper Networks, Inc. +Expires: June 4, 2018 U. Chunduri, Ed. Huawei Technologies J. Tantsura Individual - B. Decraene - Orange H. Gredler RtBrick, Inc. - October 30, 2017 + December 1, 2017 LFA selection for Multi-Homed Prefixes - draft-ietf-rtgwg-multihomed-prefix-lfa-03 + draft-ietf-rtgwg-multihomed-prefix-lfa-04 Abstract This document shares experience gained from implementing algorithms to determine Loop-Free Alternates for multi-homed prefixes. In particular, this document provides explicit inequalities that can be used to evaluate neighbors as a potential alternates for multi-homed prefixes. It also provides detailed criteria for evaluating potential alternates for external prefixes advertised by OSPF ASBRs. This documents updates and expands some of the "Routing Aspects" as @@ -41,22 +38,21 @@ 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 https://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 May 3, 2018. + This Internet-Draft will expire on June 4, 2018. Copyright Notice Copyright (c) 2017 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 (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents @@ -83,26 +79,26 @@ 4.2.4. RFC1583compatibility is set to enabled . . . . . . . 11 4.2.5. Type 7 routes . . . . . . . . . . . . . . . . . . . . 11 4.2.6. Inequalities to be applied for alternate ASBR selection . . . . . . . . . . . . . . . . . . . . . . 11 4.2.6.1. Forwarding address set to non-zero value . . . . 11 4.2.6.2. ASBRs advertising type1 and type2 cost . . . . . 12 5. LFA Extended Procedures . . . . . . . . . . . . . . . . . . . 13 5.1. Links with IGP MAX_METRIC . . . . . . . . . . . . . . . . 13 5.2. Multi Topology Considerations . . . . . . . . . . . . . . 14 6. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 15 - 7. Security Considerations . . . . . . . . . . . . . . . . . . . 15 - 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 15 - 8.1. Normative References . . . . . . . . . . . . . . . . . . 15 - 8.2. Informative References . . . . . . . . . . . . . . . . . 16 - - Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16 + 7. Contributing Authors . . . . . . . . . . . . . . . . . . . . 15 + 8. Security Considerations . . . . . . . . . . . . . . . . . . . 15 + 9. References . . . . . . . . . . . . . . . . . . . . . . . . . 16 + 9.1. Normative References . . . . . . . . . . . . . . . . . . 16 + 9.2. Informative References . . . . . . . . . . . . . . . . . 16 + Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 17 1. Introduction The use of Loop-Free Alternates (LFA) for IP Fast Reroute is specified in [RFC5286]. Section 6.1 of [RFC5286] describes a method to determine loop-free alternates for a multi-homed prefixes (MHPs). This document describes a procedure using explicit inequalities that can be used by a computing router to evaluate a neighbor as a potential alternate for a multi-homed prefix. The results obtained are equivalent to those obtained using the method described in @@ -589,58 +586,76 @@ the LFA principles laid out in [RFC5286] are actually applicable for MT IS-IS [RFC5120] LFA SPF. The primary difference in this case is, identifying the eligible-set of neighbors for each LFA computation which is done per MT ID. The eligible-set for each MT ID is determined by the presence of IGP adjacency from Source to the neighboring node on that MT-ID apart from the administrative restrictions and other checks laid out in [RFC5286]. The same is also applicable for MT-OSPF [RFC4915] or different AFs in multi instance OSPFv3 [RFC5838]. - However for MT IS-IS, if a "standart topology" is used with MT-ID #0 + However for MT IS-IS, if a "standard topology" is used with MT-ID #0 [RFC5286] and both IPv4 [RFC5305] and IPv6 routes/AFs [RFC5308] are present, then the condition of network congruency is applicable for LFA computation as well. Network congruency here refers to, having same address families provisioned on all the links and all the nodes of the network with MT-ID #0. Here with single decision process both IPv4 and IPv6 next-hops are computed for all the prefixes in the network and similarly with one LFA computation from all eligible neighbors per [RFC5286], all potential alternatives can be computed. 6. Acknowledgements Thanks to Alia Atlas and Salih K A for their useful feedback and inputs. Thanks to Stewart Bryant for being document shepherd and providing detailed review comments. -7. Security Considerations +7. Contributing Authors + + The following people contributed substantially to the content of this + document and should be considered co-authors. + + Chris Bowers + Juniper Networks, Inc. + 1194 N. Mathilda Ave, + Sunnyvale, CA 94089, USA + + Email: cbowers@juniper.ne + + Bruno Decraene + Orange, + France + + Email: bruno.decraene@orange.com + +8. Security Considerations This document does not introduce any change in any of the protocol [RFC1195] [RFC5120] [RFC2328] [RFC5838] specifications discussed here and also this does not introduce any new security issues other than as noted in the LFA base specification [RFC5286]. -8. References +9. References -8.1. Normative References +9.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC5286] Atlas, A., Ed. and A. Zinin, Ed., "Basic Specification for IP Fast Reroute: Loop-Free Alternates", RFC 5286, DOI 10.17487/RFC5286, September 2008, . -8.2. Informative References +9.2. Informative References [RFC1195] Callon, R., "Use of OSI IS-IS for routing in TCP/IP and dual environments", RFC 1195, DOI 10.17487/RFC1195, December 1990, . [RFC2328] Moy, J., "OSPF Version 2", STD 54, RFC 2328, DOI 10.17487/RFC2328, April 1998, . [RFC3137] Retana, A., Nguyen, L., White, R., Zinin, A., and D. @@ -671,48 +686,36 @@ R. Aggarwal, "Support of Address Families in OSPFv3", RFC 5838, DOI 10.17487/RFC5838, April 2010, . Authors' Addresses Pushpasis Sarkar (editor) Arrcus, Inc. Email: pushpasis.ietf@gmail.com + Shraddha Hegde Juniper Networks, Inc. Electra, Exora Business Park Bangalore, KA 560103 India Email: shraddha@juniper.net - Chris Bowers - Juniper Networks, Inc. - 1194 N. Mathilda Ave. - Sunnyvale, CA 94089 - US - - Email: cbowers@juniper.net - Uma Chunduri (editor) Huawei Technologies 2330 Central Expressway Santa Clara, CA 95050 USA Email: uma.chunduri@huawei.com Jeff Tantsura Individual Email: jefftant.ietf@gmail.com - Bruno Decraene - Orange - - Email: bruno.decraene@orange.com - Hannes Gredler RtBrick, Inc. Email: hannes@rtbrick.com