SRv6 SID Allocation Requirements
draft-cp-spring-srv6-sid-allocation-00

Document Type Active Internet-Draft (individual)
Authors Ran Chen  , Shaofu Peng 
Last updated 2020-08-17
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SPRING WG                                                        R. Chen
Internet-Draft                                                  Sh. Peng
Intended status: Standards Track                         ZTE Corporation
Expires: February 18, 2021                               August 17, 2020

                    SRv6 SID Allocation Requirements
                 draft-cp-spring-srv6-sid-allocation-00

Abstract

   This document describes a SRv6 SID allocation method.

Status of This Memo

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   This Internet-Draft will expire on February 18, 2021.

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Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Conventions used in this document . . . . . . . . . . . . . .   2
   3.  Allocating a SRv6 Compressed SID to a node  . . . . . . . . .   2
   4.  The New SR Endpoint Behaviors . . . . . . . . . . . . . . . .   3
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   5
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   5
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   5
   8.  Normative References  . . . . . . . . . . . . . . . . . . . .   5
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   6

1.  Introduction

   Segment Routing architecture [RFC8402]leverages the paradigm of
   source routing.  It can be realized in a network data plane by
   prepending the packet with a list of instructions, a.k.a.  Segment
   Identifiers (SIDs).  A segment can be encoded as a Multi-Protocol
   Label Switching (MPLS) label, IPv4 address, or IPv6 address.  Segment
   Routing can be applied in MPLS data plane by encoding 20-bits SIDs in
   MPLS label stack [RFC8660].  It also can be applied to IPv6 data
   plane by encoding a list of 128-bits SIDs in IPv6 Segment Routing
   Extension Header (SRH)[I-D.ietf-6man-segment-routing-header].

   As we know, several proposals are introduced to reduce the overhead
   of SIDs.  The main ideas of them are basically to use a Compressed
   SID to replace the complete 128 bit SID in the SID list.  The
   consequence of this is that the SID allocation space provided to each
   node will be very limited, which will limit the deployment of
   services in the network.

   This document describes an SRv6 SID allocation method to increase the
   SID allocation space.

2.  Conventions used in this document

   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.

3.  Allocating a SRv6 Compressed SID to a node

   Assign a general global SRv6 SID to the corresponding consumer type,
   which is called the container SID.  In the SID List, the container
   SID is followed by the local index or identification to indicate a
   specific segment with complete meaning.  The container SID itself is
   128bits and can be compressed to a short SID (such as 32 bits or 16

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   bits).  The local index or identifier in general can also be a short
   SID.

   For example, END.X SIDs[I-D.ietf-spring-srv6-network-programming] are
   allocated to all outbound L3 links on SRv6 nodes, and all these END.X
   SIDs occupy the global SRv6 SID resource.  Now we define a new
   allocation method: for the consumer type of L3 link, only one general
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