Path Aware Networking: Obstacles to Deployment (A Bestiary of Roads Not Taken)

Document Type Active Internet-Draft (panrg RG)
Author Spencer Dawkins 
Last updated 2021-02-10
Replaces draft-dawkins-panrg-what-not-to-do
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PANRG                                                    S. Dawkins, Ed.
Internet-Draft                                           Tencent America
Intended status: Informational                          10 February 2021
Expires: 14 August 2021

Path Aware Networking: Obstacles to Deployment (A Bestiary of Roads Not


   At the first meeting of the Path Aware Networking Research Group, the
   research group agreed to catalog and analyze past efforts to develop
   and deploy Path Aware techniques, most of which were unsuccessful or
   at most partially successful, in order to extract insights and
   lessons for path-aware networking researchers.

   This document contains that catalog and analysis.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

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

   This Internet-Draft will expire on 14 August 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 (
   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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Table of Contents

   1.  Introduction
     1.1.  What Do "Path" and "Path Awareness" Mean in this Document?
   2.  A Perspective On This Document
     2.1.  Notes for the Reader
     2.2.  A Note About Path-Aware Techniques Included In This
     2.3.  Venue for Discussion of this Document
     2.4.  Architectural Guidance
     2.5.  Terminology Used in this Document
     2.6.  Methodology for Contributions
   3.  Applying the Lessons We've Learned
   4.  Summary of Lessons Learned
     4.1.  Justifying Deployment
     4.2.  Providing Benefits for Early Adopters
     4.3.  Providing Benefits During Partial Deployment
     4.4.  Outperforming End-to-end Protocol Mechanisms
     4.5.  Paying for Path Aware Techniques
     4.6.  Impact on Operational Practices
     4.7.  Per-connection State
     4.8.  Keeping Traffic on Fast-paths
     4.9.  Endpoints Trusting Intermediate Nodes
     4.10. Intermediate Nodes Trusting Endpoints
     4.11. Reacting to Distant Signals
     4.12. Support in Endpoint Protocol Stacks
   5.  Future Work
   6.  Contributions
     6.1.  Stream Transport (ST, ST2, ST2+)
       6.1.1.  Reasons for Non-deployment
       6.1.2.  Lessons Learned.
     6.2.  Integrated Services (IntServ)
       6.2.1.  Reasons for Non-deployment
       6.2.2.  Lessons Learned.
     6.3.  Quick-Start TCP
       6.3.1.  Reasons for Non-deployment
       6.3.2.  Lessons Learned
     6.4.  ICMP Source Quench
       6.4.1.  Reasons for Non-deployment
       6.4.2.  Lessons Learned
     6.5.  Triggers for Transport (TRIGTRAN)
       6.5.1.  Reasons for Non-deployment
       6.5.2.  Lessons Learned.
     6.6.  Shim6
       6.6.1.  Reasons for Non-deployment
       6.6.2.  Lessons Learned
       6.6.3.  Addendum on MultiPath TCP
     6.7.  Next Steps in Signaling (NSIS)
       6.7.1.  Reasons for Non-deployment
       6.7.2.  Lessons Learned
     6.8.  IPv6 Flow Label
       6.8.1.  Reasons for Non-deployment
       6.8.2.  Lessons Learned
   7.  Security Considerations
   8.  IANA Considerations
   9.  Acknowledgments
   10. Informative References
   Author's Address

1.  Introduction

   This document describes the lessons that IETF participants have
   learned (and learned the hard way) about Path Aware Networking over a
   period of several decades, and provides an analysis of reasons why
   various Path Aware Networking techniques have seen limited or no

1.1.  What Do "Path" and "Path Awareness" Mean in this Document?

   One of the first questions reviewers of this document have asked is
   "what's the definition of a path, and what's the definition of path
   awareness?"  That is not an easy question to answer for this

   These terms have definitions in other [PANRG] documents, and are
   still the subject of some discussion in the research group, as of the
   date of this document.  But because this document reflects work
   performed over several decades, the technologies described in
   Section 6 significantly predate the current definitions of "path" and
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