Source Packet Routing in Networking (SPRING) Problem Statement and Requirements
RFC 7855

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Internet Engineering Task Force (IETF)                   S. Previdi, Ed.
Request for Comments: 7855                              C. Filsfils, Ed.
Category: Informational                              Cisco Systems, Inc.
ISSN: 2070-1721                                              B. Decraene
                                                            S. Litkowski
                                                                  Orange
                                                            M. Horneffer
                                                        Deutsche Telekom
                                                               R. Shakir
                                               Jive Communications, Inc.
                                                                May 2016

              Source Packet Routing in Networking (SPRING)
                   Problem Statement and Requirements

Abstract

   The ability for a node to specify a forwarding path, other than the
   normal shortest path, that a particular packet will traverse,
   benefits a number of network functions.  Source-based routing
   mechanisms have previously been specified for network protocols but
   have not seen widespread adoption.  In this context, the term
   "source" means "the point at which the explicit route is imposed";
   therefore, it is not limited to the originator of the packet (i.e.,
   the node imposing the explicit route may be the ingress node of an
   operator's network).

   This document outlines various use cases, with their requirements,
   that need to be taken into account by the Source Packet Routing in
   Networking (SPRING) architecture for unicast traffic.  Multicast use
   cases and requirements are out of scope for this document.

Status of This Memo

   This document is not an Internet Standards Track specification; it is
   published for informational purposes.

   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).  Not all documents
   approved by the IESG are a candidate for any level of Internet
   Standard; see Section 2 of RFC 5741.

   Information about the current status of this document, any errata,
   and how to provide feedback on it may be obtained at
   http://www.rfc-editor.org/info/rfc7855.

Previdi, et al.               Informational                     [Page 1]
RFC 7855                SPRING Problem Statement                May 2016

Copyright Notice

   Copyright (c) 2016 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
   (http://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
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   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  . . . . . . . . . . . . . . . . . . . . . . . .   3
     1.1.  Requirements Language . . . . . . . . . . . . . . . . . .   4
   2.  Data Planes . . . . . . . . . . . . . . . . . . . . . . . . .   4
   3.  SPRING Use Cases  . . . . . . . . . . . . . . . . . . . . . .   4
     3.1.  IGP-Based MPLS Tunneling  . . . . . . . . . . . . . . . .   4
       3.1.1.  Example of IGP-Based MPLS Tunnels . . . . . . . . . .   5
     3.2.  Fast Reroute (FRR)  . . . . . . . . . . . . . . . . . . .   5
     3.3.  Traffic Engineering . . . . . . . . . . . . . . . . . . .   6
       3.3.1.  Examples of Traffic-Engineering Use Cases . . . . . .   7
     3.4.  Interoperability with Non-SPRING Nodes  . . . . . . . . .  13
   4.  Security Considerations . . . . . . . . . . . . . . . . . . .  13
   5.  Manageability Considerations  . . . . . . . . . . . . . . . .  15
   6.  References  . . . . . . . . . . . . . . . . . . . . . . . . .  16
     6.1.  Normative References  . . . . . . . . . . . . . . . . . .  16
     6.2.  Informative References  . . . . . . . . . . . . . . . . .  16
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .  18
   Contributors  . . . . . . . . . . . . . . . . . . . . . . . . . .  18
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .  18

Previdi, et al.               Informational                     [Page 2]
RFC 7855                SPRING Problem Statement                May 2016

1.  Introduction

   The ability for a node to specify a unicast forwarding path, other
   than the normal shortest path, that a particular packet will
   traverse, benefits a number of network functions, for example: