Slipmux: Using an UART interface for diagnostics, configuration, and packet transfer
draft-bormann-t2trg-slipmux-00

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Network Working Group                                         C. Bormann
Internet-Draft                                   Universitaet Bremen TZI
Intended status: Informational                                 T. Kaupat
Expires: July 17, 2017                                         Lobaro UG
                                                        January 13, 2017

  Slipmux: Using an UART interface for diagnostics, configuration, and
                            packet transfer
                     draft-bormann-t2trg-slipmux-00

Abstract

   Many research and maker platforms for Internet of Things
   experimentation offer a serial interface.  This is often used for
   programming, diagnostic output, as well as a crude command interface
   ("AT interface").  Alternatively, it is often used with SLIP
   (RFC1055) to transfer IP packets only.

   The present report describes how to use a single serial interface for
   diagnostics, configuration commands and state readback, as well as
   packet transfer.

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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   This Internet-Draft will expire on July 17, 2017.

Copyright Notice

   Copyright (c) 2017 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

Bormann & Kaupat          Expires July 17, 2017                 [Page 1]
Internet-Draft                UART slipmux                  January 2017

   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
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   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Terminology . . . . . . . . . . . . . . . . . . . . . . .   2
   2.  Using a UART interface  . . . . . . . . . . . . . . . . . . .   3
   3.  Packet Transfer . . . . . . . . . . . . . . . . . . . . . . .   3
   4.  Diagnostics Transfer  . . . . . . . . . . . . . . . . . . . .   4
   5.  Configuration . . . . . . . . . . . . . . . . . . . . . . . .   4
   6.  Framing considerations  . . . . . . . . . . . . . . . . . . .   5
   7.  Discussion  . . . . . . . . . . . . . . . . . . . . . . . . .   5
     7.1.  Why no shell? . . . . . . . . . . . . . . . . . . . . . .   5
     7.2.  Frame aborts  . . . . . . . . . . . . . . . . . . . . . .   6
     7.3.  Unknown initial bytes . . . . . . . . . . . . . . . . . .   6
   8.  IANA Considerations . . . . . . . . . . . . . . . . . . . . .   7
   9.  Security Considerations . . . . . . . . . . . . . . . . . . .   7
   10. References  . . . . . . . . . . . . . . . . . . . . . . . . .   8
     10.1.  Normative References . . . . . . . . . . . . . . . . . .   8
     10.2.  Informative References . . . . . . . . . . . . . . . . .   8
   Appendix A.  Implementation . . . . . . . . . . . . . . . . . . .   8
   Acknowledgements  . . . . . . . . . . . . . . . . . . . . . . . .   9
   Authors' Addresses  . . . . . . . . . . . . . . . . . . . . . . .   9

1.  Introduction

   Many research and maker hardware modules for Internet of Things
   experimentation ("platforms") offer a serial ("UART") interface.
   This is often used for programming, diagnostic output, as well as a
   crude command interface ("AT interface").  Alternatively, it is used
   with SLIP (RFC1055) to transfer IP packets only; this may require the
   use of another serial interface for diagnostics and configuration.

   The present report describes how to use a single serial interface for
   diagnostics, configuration commands and state readback, as well as
   packet transfer.

1.1.  Terminology

   The term "byte" is used in its now customary sense as a synonym for
   "octet".  Where bit arithmetic is explained, this document uses the
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