6TiSCH X. Vilajosana, Ed.
Internet-Draft Universitat Oberta de Catalunya
Intended status: Best Current Practice K. Pister
Expires: July 24, 2017 University of California Berkeley
January 20, 2017

Minimal 6TiSCH Configuration


This document describes a minimal mode of operation for a 6TiSCH Network. A minimal mode of operation is a baseline set of protocols, recommended configurations and modes of operation sufficient to enable a 6TiSCH functional network. 6TiSCH provides IPv6 connectivity over a Time Synchronized Channel Hopping (TSCH) mesh composed of IEEE Std 802.15.4 TSCH links. This minimal mode uses a collection of protocols with the respective configurations, including the 6LoWPAN framework, enabling interoperable IPv6 connectivity over IEEE Std 802.15.4 TSCH. This minimal configuration provides the necessary bandwidth for network and security bootstrap and defines the proper link between the IETF protocols that interface to the IEEE Std 802.15.4 TSCH. This minimal mode of operation should be implemented by all 6TiSCH compliant devices.

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 24, 2017.

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Table of Contents

1. Introduction

A 6TiSCH Network provides IPv6 connectivity [RFC2460] over a Time Synchronized Channel Hopping (TSCH) mesh [RFC7554] composed of IEEE Std 802.15.4 TSCH links [IEEE802154-2015]. IPv6 connectivity is obtained by the use of the 6LoWPAN framework ([RFC4944], [RFC6282], [RFC8025],[I-D.ietf-6lo-routing-dispatch] and [RFC6775]), RPL [RFC6550], and its Objective Function 0 (OF0) [RFC6552].

This specification defines operational parameters and procedures for a minimal mode of operation to build a 6TiSCH Network. Any 6TiSCH complaint device SHOULD implement this mode of operation. This operational parameters configuration provides the necessary bandwidth for nodes to bootstrap the network. The bootstrap process includes initial network configuration and security bootstrap. In this specification, the 802.15.4 TSCH mode, the 6LoWPAN framework, RPL [RFC6550], and its Objective Function 0 (OF0) [RFC6552], are used unmodified. Parameters and particular operations of TSCH are specified to guarantee interoperability between nodes in a 6TiSCH Network. RPL is specified to provide the framework for time synchronization in an 802.15.4 TSCH network. The specifics for interoperable interaction between RPL and TSCH are described.

In a 6TiSCH network, nodes follow a communication schedule as per 802.15.4 TSCH. In it, nodes learn the schedule of the network when joining. When following this specification, the learned schedule is the same for all nodes and does not change over time. Future specifications may define mechanisms for dynamically managing the communication schedule. Dynamic scheduling solutions are out of scope of this document.

IPv6 addressing and compression are achieved by the 6LoWPAN framework. The framework includes [RFC4944], [RFC6282], [RFC8025], the 6LoWPAN Routing Header dispatch [I-D.ietf-6lo-routing-dispatch] for addressing and header compression, and [RFC6775] for duplicate address detection (DAD) and address resolution.

More advanced work is expected in the future to complement the Minimal Configuration with dynamic operations that can adapt the schedule to the needs of the traffic at run time.

2. Requirements Language

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119 [RFC2119].

3. Terminology

This document uses terminology from [I-D.ietf-6tisch-terminology]. The following concepts are used in this document:

We use "802.15.4" as a short version of "IEEE Std 802.15.4" in this document.
Start of Frame Delimiter.
Join Metric:
Field in the TSCH Synchronization IE. Number of hops separating the node sending the EB, and the PAN coordinator.

4. IEEE Std 802.15.4 Settings

An implementation compliant to this specification MUST implement IEEE Std 802.15.4 [IEEE802154-2015] in "timeslotted channel hopping" (TSCH) mode.

The remainder of this section details the RECOMMENDED TSCH settings, which are summarized in Figure 1. A node MAY use different values. Any of the properties marked in the EB column are announced in the Enhanced Beacons (EB) the nodes send [IEEE802154-2015] and learned by those joining the network. Changing their value hence means changing the contents of the EB.

In case of discrepancy between the values in this specification and IEEE Std 802.15.4 [IEEE802154-2015], the IEEE standard has precedence.