Signaling RSVP-TE Tunnels on a Shared MPLS Forwarding Plane
RFC 8577
Document | Type | RFC - Proposed Standard (April 2019; Errata) | |
---|---|---|---|
Authors | Harish Sitaraman , Vishnu Beeram , Tejal Parikh , Tarek Saad | ||
Last updated | 2020-01-20 | ||
Replaces | draft-sitaraman-mpls-rsvp-shared-labels | ||
Stream | Internent Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized with errata bibtex | ||
Reviews | |||
Stream | WG state | Submitted to IESG for Publication | |
Document shepherd | Loa Andersson | ||
Shepherd write-up | Show (last changed 2018-11-05) | ||
IESG | IESG state | RFC 8577 (Proposed Standard) | |
Action Holders |
(None)
|
||
Consensus Boilerplate | Yes | ||
Telechat date | |||
Responsible AD | Deborah Brungard | ||
Send notices to | Loa Andersson <loa@pi.nu> | ||
IANA | IANA review state | Version Changed - Review Needed | |
IANA action state | RFC-Ed-Ack |
Internet Engineering Task Force (IETF) H. Sitaraman Request for Comments: 8577 V. Beeram Category: Standards Track Juniper Networks ISSN: 2070-1721 T. Parikh Verizon T. Saad Cisco Systems April 2019 Signaling RSVP-TE Tunnels on a Shared MPLS Forwarding Plane Abstract As the scale of MPLS RSVP-TE networks has grown, the number of Label Switched Paths (LSPs) supported by individual network elements has increased. Various implementation recommendations have been proposed to manage the resulting increase in the amount of control-plane state information. However, those changes have had no effect on the number of labels that a transit Label Switching Router (LSR) has to support in the forwarding plane. That number is governed by the number of LSPs transiting or terminated at the LSR and is directly related to the total LSP state in the control plane. This document defines a mechanism to prevent the maximum size of the label space limit on an LSR from being a constraint to control-plane scaling on that node. It introduces the notion of preinstalled 'per-TE link labels' that can be shared by MPLS RSVP-TE LSPs that traverse these TE links. This approach significantly reduces the forwarding-plane state required to support a large number of LSPs. This couples the feature benefits of the RSVP-TE control plane with the simplicity of the Segment Routing (SR) MPLS forwarding plane. Status of This Memo This is an Internet Standards Track document. This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841. Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at https://www.rfc-editor.org/info/rfc8577. Sitaraman, et al. Standards Track [Page 1] RFC 8577 RSVP-TE Shared Labels April 2019 Copyright Notice Copyright (c) 2019 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 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. Sitaraman, et al. Standards Track [Page 2] RFC 8577 RSVP-TE Shared Labels April 2019 Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5 2.1. Requirements Language . . . . . . . . . . . . . . . . . . 6 3. Allocation of TE Link Labels . . . . . . . . . . . . . . . . 6 4. Segment Routed RSVP-TE Tunnel Setup . . . . . . . . . . . . . 6 5. Delegating Label Stack Imposition . . . . . . . . . . . . . . 8 5.1. Stacking at the Ingress . . . . . . . . . . . . . . . . . 8 5.1.1. Stack to Reach Delegation Hop . . . . . . . . . . . . 9 5.1.2. Stack to Reach Egress . . . . . . . . . . . . . . . . 10 5.2. Explicit Delegation . . . . . . . . . . . . . . . . . . . 11 5.3. Automatic Delegation . . . . . . . . . . . . . . . . . . 11 5.3.1. Effective Transport Label-Stack Depth (ETLD) . . . . 11 6. Mixing TE Link Labels and Regular Labels in an RSVP-TE Tunnel 13 7. Construction of Label Stacks . . . . . . . . . . . . . . . . 14 8. Facility Backup Protection . . . . . . . . . . . . . . . . . 14 8.1. Link Protection . . . . . . . . . . . . . . . . . . . . . 14 9. Protocol Extensions . . . . . . . . . . . . . . . . . . . . . 15 9.1. Requirements . . . . . . . . . . . . . . . . . . . . . . 15 9.2. Attribute Flags TLV: TE Link Label . . . . . . . . . . . 16 9.3. RRO Label Sub-object Flag: TE Link Label . . . . . . . . 16 9.4. Attribute Flags TLV: LSI-D . . . . . . . . . . . . . . . 16Show full document text