6TiSCH                                                   D. Dujovne, Ed.
Internet-Draft                                Universidad Diego Portales
Intended status: Informational                         September 9, 2015
Expires: March 12, 2016


                  Deterministic Networks Gap Analysis
                  draft-dujovne-detnet-gap-analysis-01

Abstract

   This document introduces and describes several conditions and use
   cases where the use of an IP-based layer-3 and up is required to
   provide a complete networking solution to deterministic networks.
   The contents of this work is a gap analysis to contribute to the
   design and development of a number of complimentary modules to
   provide IP-enabled networking for deterministic networks.

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   This Internet-Draft will expire on March 12, 2016.

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   document authors.  All rights reserved.

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   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Assumptions . . . . . . . . . . . . . . . . . . . . . . . . .   2
   3.  Gap Analysis  . . . . . . . . . . . . . . . . . . . . . . . .   3
     3.1.  6TiSCH Track management . . . . . . . . . . . . . . . . .   3
     3.2.  Deterministic Payload on MPLS . . . . . . . . . . . . . .   3
     3.3.  Traffic Specification implementation for PCE  . . . . . .   3
     3.4.  Packet-track ID . . . . . . . . . . . . . . . . . . . . .   3
     3.5.  Packet Redundancy Protocol  . . . . . . . . . . . . . . .   4
   4.  Acknowledgments . . . . . . . . . . . . . . . . . . . . . . .   4
   5.  Informative References  . . . . . . . . . . . . . . . . . . .   4
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .   4

1.  Introduction

   The first step to become detnet networks was taken at the stub
   networks such as 6TiSCH-based ones [I-D.ietf-6tisch-tsch], meaning
   those simple networks that connect the endpoints to one or several
   gateways, thus enabling both a predictable delay and a very high
   reliability.  These two characteristics must be preserved along the
   the multi-hop path between source and destination, thus requiring a
   fully-fledged deterministic end-to-end network including management
   services to achieve this goal.  This is achieved by installing tracks
   with all the deterministic capabilities.

   The evolution towards these kinds of intermediate and backbone
   deterministic networks has been taken up to the MAC layer by the IEEE
   by defining several standards to provide building blocks to guarantee
   a predictable delay, such as buffers, queues and schedulers.  The
   configuration, use, coordination, resources management and control of
   these blocks must be achieved at a higher layer, tightly linked to
   the routing scheme.  Many applications are currently lacking this
   kind of solution, forcing bandwidth overprovisioning to reduce packet
   loss and delay uncertainty.

2.  Assumptions

   Current packet loss and delay jitter provided by IP networks are not
   enough for industrial applications

   Realtime audio and video for reliable content distribution in local
   networks is cannot be achieved without time-scheduled IP networks





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   End-to-end delay and packet loss guarantees cannot be provided
   without a managed deterministic network

3.  Gap Analysis

3.1.  6TiSCH Track management

   6TiSCH requires the installation of tracks along a path with
   deterministic capabilities, including scheduled transmissions,
   intermediate queue management, synchronization and path and packet
   redundnacy among others.  The mechanism to achieve such a path is
   achieved by using PCE/SDN operations as defined on RFC 7149
   [RFC7149].

   On 6TiSCH, IPv6 packets are carried on installed tracks; to reduce
   resource usage, there is also the need to forward IPv6 packets by
   opportunistic reuse of track slots and also reuse link bundle slots
   to forward schedule packets that missed their track.  Both mechanisms
   require the use of Deterministic Networking managament capabilities.

3.2.  Deterministic Payload on MPLS

   There are certain Non-IP protocols such as Profibus and Modbus which
   can be carried as IPv6 payload as long as this traffic is treated as
   Deterministic; this can be achieved by the use of MPLS and and a
   specific mangement module for layer-2 path redundancy, such as
   Parallel Redundancy Protocol.

3.3.  Traffic Specification implementation for PCE

   There are several issues on the implementation of Traffic
   Specification for the PCE
   [I-D.ietf-teas-interconnected-te-info-exchange]:

      A TEAS adaptation to carry the topology (neighbors, link quality,
      interference test, etc.) and capabilities (buffers, queues and
      timers) from the point of view of the individual devices.

      A CCAMP/RSVP-TE adaptation to program the individual tracks

      An adaptation of PCEP to push an individual device schedule

3.4.  Packet-track ID

   Track ID on packets is not defined yet; the use of Diffserv/DSCP and
   MPLS (and G-MPLS for 6TiSCH) are possible alternatives





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3.5.  Packet Redundancy Protocol

   There is a need to define a Packet Redundancy Protocol (PRP) for
   deterministic networks, including the PRP sequence number which can
   be defined by the ASN.

4.  Acknowledgments

   Thanks to the Fondecyt (CONICYT-Chile) 11121475 Project.

5.  Informative References

   [I-D.ietf-6tisch-tsch]
              Watteyne, T., Palattella, M., and L. Grieco, "Using
              IEEE802.15.4e TSCH in an IoT context: Overview, Problem
              Statement and Goals", draft-ietf-6tisch-tsch-06 (work in
              progress), March 2015.

   [I-D.ietf-teas-interconnected-te-info-exchange]
              Farrel, A., Drake, J., Bitar, N., Swallow, G., Ceccarelli,
              D., and X. Zhang, "Problem Statement and Architecture for
              Information Exchange Between Interconnected Traffic
              Engineered Networks", draft-ietf-teas-interconnected-te-
              info-exchange-02 (work in progress), March 2015.

   [RFC7149]  Boucadair, M. and C. Jacquenet, "Software-Defined
              Networking: A Perspective from within a Service Provider
              Environment", RFC 7149, DOI 10.17487/RFC7149, March 2014,
              <http://www.rfc-editor.org/info/rfc7149>.

Author's Address

   Diego Dujovne (editor)
   Universidad Diego Portales
   Escuela de Informatica y Telecomunicaciones
   Av. Ejercito 441
   Santiago, Region Metropolitana
   Chile

   Phone: +56 (2) 676-8121
   Email: diego.dujovne@mail.udp.cl










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