BGP Request for Advertising Candidate Path of Segment Routing TE Policies
draft-li-ldr-bgp-request-cp-sr-te-policy-00
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Network Working Group Z. Li
Internet-Draft Li
Intended status: Standards Track Huawei
Expires: January 9, 2020 July 08, 2019
BGP Request for Advertising Candidate Path of Segment Routing TE
Policies
draft-li-ldr-bgp-request-cp-sr-te-policy-00
Abstract
An SR Policy is a set of candidate paths. The headend of an SR
Policy may learn multiple candidate paths for an SR Policy via a
number of different mechanisms, e.g., CLI, NetConf, PCEP, or BGP.
BGP distribute candidate paths has been defined in
[I-D.ietf-idr-segment-routing-te-policy]. This document defines an
extension of BGP to request BGP speaker(controller) advertise the
candidate paths. The goal is to unify the protocol when the
candidate path of SR Policy provision is via BGP to reduce the
network complexity and potential bugs cause by different protocol
interactions.
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].
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 January 9, 2020.
Li & Li Expires January 9, 2020 [Page 1]
Internet-Draft BGP Trigger SR TE Policies July 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.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Overview of BGP UPDATE Message for Request SR TE policy
candidate path advertising . . . . . . . . . . . . . . . . . 3
4. BGP request UPDATE Message Encoding . . . . . . . . . . . . . 4
4.1. Extention of SR Policy NLRI . . . . . . . . . . . . . . . 4
4.2. New SR Policy and Tunnel Encapsulation Attribute . . . . 5
4.3. New SR Policy Sub-TLVs . . . . . . . . . . . . . . . . . 5
4.3.1. LSPA Sub-TLV . . . . . . . . . . . . . . . . . . . . 5
4.3.2. SVEC Sub-TLV . . . . . . . . . . . . . . . . . . . . 7
4.3.3. Metric Sub-TLV . . . . . . . . . . . . . . . . . . . 8
4.3.4. Include Route Sub-TLV . . . . . . . . . . . . . . . . 9
4.3.5. Load-Balancing Sub-TLV . . . . . . . . . . . . . . . 10
5. IANA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . 11
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 11
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12
1. Introduction
An SR Policy defined in [I-D.ietf-spring-segment-routing-policy] is a
set of candidate paths. The headend of an SR Policy may be informed
by various means including: Configuration, PCEP[RFC8281] or
BGP[I-D.ietf-idr-segment-routing-te-policy] . All these mechanisms
are PCE/Controller initiated, but in some situations headend maybe
want pull one or a set of candidate paths from PCE/Controller rather
than get all information passively. Actually PCEP can use request
and reply messages defined in [RFC5440]to match this requirement but
the mechanism is not clear when controller advertise candidate path
via BGP protocol.
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