Discovery of path characteristics using STUN
draft-ietf-tram-stun-path-data-00

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Replaced by draft-ietf-tram-measurement-rtt-loss
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TRAM                                                            T. Reddy
Internet-Draft                                                   D. Wing
Intended status: Standards Track                            P. Martinsen
Expires: October 9, 2015                                           Cisco
                                                                V. Singh
                                                            callstats.io
                                                           April 7, 2015

              Discovery of path characteristics using STUN
                   draft-ietf-tram-stun-path-data-00

Abstract

   A host with multiple interfaces needs to choose the best interface
   for communication.  Oftentimes, this decision is based on a static
   configuration and does not consider the path characteristics, which
   may affect the user experience.

   This document describes a mechanism for an endpoint to discover the
   path characteristics using Session Traversal Utilities for NAT (STUN)
   messages.  The measurement information can then be used to influence
   the endpoint's Interactive Connectivity Establishment (ICE) candidate
   pair selection algorithm.

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
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   This Internet-Draft will expire on October 9, 2015.

Copyright Notice

   Copyright (c) 2015 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

Reddy, et al.            Expires October 9, 2015                [Page 1]
Internet-Draft          STUN Path Characteristics             April 2015

   This document is subject to BCP 78 and the IETF Trust's Legal
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   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
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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  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Notational Conventions  . . . . . . . . . . . . . . . . . . .   3
   3.  Path characteristics determination mechanism  . . . . . . . .   3
     3.1.  The PATH-CHARACTERISTIC attribute in request  . . . . . .   4
     3.2.  The PATH-CHARACTERISTIC attribute in response . . . . . .   5
     3.3.  Example Operation . . . . . . . . . . . . . . . . . . . .   6
   4.  Usecases  . . . . . . . . . . . . . . . . . . . . . . . . . .   6
   5.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   6.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   7.  Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .   8
   8.  References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     8.1.  Normative References  . . . . . . . . . . . . . . . . . .   8
     8.2.  Informative References  . . . . . . . . . . . . . . . . .   8
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   8

1.  Introduction

   The ICE [RFC5245] mechanism uses a prioritization formula to order
   the candidate pairs and perform connectivity checks, in which the
   most preferred address pairs are tested first and when a sufficiently
   good pair is discovered, that pair is used for communications and
   further connectivity tests are stopped.  This approach works well for
   an endpoint with a single interface, but is too simplistic for
   endpoints with multiple interfaces, wherein a candidate pair with a
   lower priority might infact have better path characteristics (e.g.,
   round-trip time, loss, etc.).  The ICE connectivity checks can assist
   in measuring the path characteristics, but as currently defined, the
   STUN responses to re-transmitted requests are indistinguishable from
   each other.

   This draft extends STUN [RFC5389] to distinguish STUN responses to
   re-transmitted requests and this assists the client in determining
   the path characteristics like round-trip time (RTT) and packet loss
   in each direction between endpoints.  These metrics can then be used
   by the controlling agent to influence the ICE candidate pair
   priorities.

Reddy, et al.            Expires October 9, 2015                [Page 2]
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