--- 1/draft-ietf-mpls-rmr-06.txt 2018-03-05 00:13:48.348509077 -0800 +++ 2/draft-ietf-mpls-rmr-07.txt 2018-03-05 00:13:48.380509832 -0800 @@ -1,19 +1,19 @@ MPLS WG K. Kompella Internet-Draft Juniper Networks, Inc. Intended status: Standards Track L. Contreras -Expires: July 7, 2018 Telefonica - January 3, 2018 +Expires: September 5, 2018 Telefonica + March 4, 2018 Resilient MPLS Rings - draft-ietf-mpls-rmr-06 + draft-ietf-mpls-rmr-07 Abstract This document describes the use of the MPLS control and data planes on ring topologies. It describes the special nature of rings, and proceeds to show how MPLS can be effectively used in such topologies. It describes how MPLS rings are configured, auto-discovered and signaled, as well as how the data plane works. Companion documents describe the details of discovery and signaling for specific protocols. @@ -32,21 +32,21 @@ 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 July 7, 2018. + This Internet-Draft will expire on September 5, 2018. Copyright Notice Copyright (c) 2018 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 @@ -550,39 +550,42 @@ 7. Advanced Topics 7.1. Half-rings In some cases, a ring H may be incomplete, either because H is permanently missing a link (not just because of a failure), or because the link required to complete H is in a different IGP area. Either way, the ring discovery algorithm will fail. We call such a ring a "half-ring". Half-rings are sufficiently common that finding a way to deal with them effectively is a useful problem to solve. + This topic will not be addressed in this document; that task is left + for a future document. 7.2. Hub Node Resilience Let's call the node(s) that connect a ring to the rest of the network "hub node(s)" (usually, there are a pair of hub nodes.) Suppose a ring has two hub nodes H1 and H2. Suppose further that a non-hub ring node X wants to send traffic to some node Z outside the ring. This could be done, say, by having targeted LDP (T-LDP) sessions from H1 and H2 to X advertising LDP reachability to Z via H1 (H2); there would be a two-label stack from X to reach Z. Say that to reach Z, X prefers H1; thus, traffic from X to Z will first go to H1 via a ring LSP, then to Z via LDP. If H1 fails, traffic from X to Z will drop until the T-LDP session from H1 to Z fails, the IGP reconverges, and H2's label to Z is chosen. Thereafter, traffic will go from X to H2 via a ring LSP, then to Z via LDP. However, this convergence could take a long time. Since this is a very common and important situation, it is again a - useful problem to solve. + useful problem to solve. However, this topic too will not be + addressed in this document; that task is left for a future document. 8. Security Considerations It is not anticipated that either the notion of MPLS rings or the extensions to various protocols to support them will cause new security loopholes. As this document is updated, this section will also be updated. 9. Acknowledgments