SRIFT: Segment Routing in Fat Trees
draft-zzhang-rift-sr-03

Document Type Active Internet-Draft (individual)
Authors Zhaohui Zhang  , Jeff Tantsura  , Jordan Head  , Don Fedyk 
Last updated 2021-02-22
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RIFT                                                            Z. Zhang
Internet-Draft                                               J. Tantsura
Intended status: Standards Track                                 J. Head
Expires: 26 August 2021                                 Juniper Networks
                                                                D. Fedyk
                                                              Individual
                                                        22 February 2021

                  SRIFT: Segment Routing in Fat Trees
                        draft-zzhang-rift-sr-03

Abstract

   This document specifies signaling procedures for Segment Routing in
   RIFT.  Each node's loopback address, Segment Routing Global Block
   (SRGB) and Node Segment Identifier (Node-SID), which are typically
   assigned by a configuration management system and distibuted by
   routing protocols, are distributed southbound from the Top Of Fabric
   (TOF) nodes via RIFT's Key-Value distribution mechanism, so that each
   node can compute how to reach a segment represented by the active SID
   in a packet.  An SR controller signals SR policies to ingress nodes
   so that they can send packets with a desired segment list to steer
   traffic.

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 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
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   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on 26 August 2021.

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Internet-Draft                    SRIFT                    February 2021

Copyright Notice

   Copyright (c) 2021 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
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   provided without warranty as described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  SR in RIFT (SRIFT)  . . . . . . . . . . . . . . . . . . . . .   4
   3.  Well-Known KV Registry Values . . . . . . . . . . . . . . . .   6
     3.1.  SRIFT Node Key-Type . . . . . . . . . . . . . . . . . . .   6
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   5.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   7
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   7
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .   7
     6.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   Before we discuss the SR procedures for RIFT, let us first review how
   SR works with OSPF [RFC8665] and IS-IS [RFC8667].

   Each node is provisioned with a loopback address as well as SRGB and
   Node-SID values.  The loopback address and Node-SID are centrally
   coordinated and are unique per-node within the SR network.  These
   values are then communicated to each node out-of-band and stored as
   configuration information.  Communication could be done via primitive
   pen and paper or via modern signaling (Netconf/YANG) from a
   configuration management system.

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   SRGB information represents the label range of the "global" labels
   that can be allocated on a particular node for SR.  SRGB could have
   more than one contiguous range of labeks allocated to it.  It is
   comprised of the first available label value and the total number of
   available labels per range.  While in modern networks it is common
   for each node to have identical SRGB values so that a Node-SID will
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