Signaling MSD (Maximum SID Depth) using IS-IS
draft-ietf-isis-segment-routing-msd-15
The information below is for an old version of the document | |||
---|---|---|---|
Document | Type | Active Internet-Draft (lsr WG) | |
Authors | Jeff Tantsura , Uma Chunduri , Sam Aldrin , Les Ginsberg | ||
Last updated | 2018-09-12 (latest revision 2018-08-29) | ||
Replaces | draft-tantsura-isis-segment-routing-msd | ||
Stream | IETF | ||
Intended RFC status | Proposed Standard | ||
Formats | pdf htmlized (tools) htmlized bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Christian Hopps | ||
Shepherd write-up | Show (last changed 2018-06-16) | ||
IESG | IESG state | IESG Evaluation | |
Consensus Boilerplate | Yes | ||
Telechat date |
Needs 4 more YES or NO OBJECTION positions to pass. |
||
Responsible AD | Alvaro Retana | ||
Send notices to | Christian Hopps <chopps@chopps.org>, aretana.ietf@gmail.com | ||
IANA | IANA review state | IANA OK - Actions Needed |
IS-IS Working Group J. Tantsura Internet-Draft Nuage Networks Intended status: Standards Track U. Chunduri Expires: March 2, 2019 Huawei Technologies S. Aldrin Google, Inc L. Ginsberg Cisco Systems August 29, 2018 Signaling MSD (Maximum SID Depth) using IS-IS draft-ietf-isis-segment-routing-msd-15 Abstract This document defines a way for an Intermediate System to Intermediate System (IS-IS) Router to advertise multiple types of supported Maximum SID Depths (MSDs) at node and/or link granularity. Such advertisements allow entities (e.g., centralized controllers) to determine whether a particular SID stack can be supported in a given network. This document only defines one type of MSD maximum label imposition, but defines an encoding that can support other MSD types. 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 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 March 2, 2019. 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 Tantsura, et al. Expires March 2, 2019 [Page 1] Internet-Draft draft-ietf-isis-segment-routing-msd August 2018 (https://trustee.ietf.org/license-info) in effect on the date of 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. Terminology . . . . . . . . . . . . . . . . . . . . . . . 3 1.2. Requirements Language . . . . . . . . . . . . . . . . . . 3 2. Node MSD Advertisement . . . . . . . . . . . . . . . . . . . 3 3. Link MSD Advertisement . . . . . . . . . . . . . . . . . . . 4 4. Procedures for using Node and Link MSD Advertisements . . . . 5 5. Base MPLS Imposition MSD . . . . . . . . . . . . . . . . . . 6 6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 6 7. Security Considerations . . . . . . . . . . . . . . . . . . . 7 8. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 7 9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 8 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 8 10.1. Normative References . . . . . . . . . . . . . . . . . . 8 10.2. Informative References . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 9 1. Introduction When Segment Routing (SR) paths are computed by a centralized controller, it is critical that the controller learns the Maximum SID Depth (MSD) that can be imposed at each node/link a given SR path to insure that the Segment Identifier (SID) stack depth of a computed path doesn't exceed the number of SIDs the node is capable of imposing. Path Computation Element Protocol (PCEP) SR extensions draft [I-D.ietf-pce-segment-routing] signals MSD in SR Path Computation Element (PCE) Capability TLV and METRIC Object. However, if PCEP is not supported/configured on the head-end of an SR tunnel or a Binding-SID anchor node and controller does not participate in IGP routing, it has no way to learn the MSD of nodes and links. BGP-LS (Distribution of Link-State and TE Information using Border Gateway Protocol) [RFC7752] defines a way to expose topology and associated attributes and capabilities of the nodes in that topology to a centralized controller. MSD signaling by BGP-LS has been defined inShow full document text