A new IETF working group has been proposed in the Internet Area. The IESG has not made any determination yet. The following draft charter was submitted, and is provided for informational purposes only. Please send your comments to the IESG mailing list (iesg at ietf.org) by 2013-09-23. IPv6 over the TSCH mode of IEEE 802.15.4e (6tisch) ------------------------------------------------ Current Status: Proposed WG Chairs: Pascal Thubert <pthubert@cisco.com> Thomas Watteyne <watteyne@eecs.berkeley.edu> Assigned Area Director: Ted Lemon <ted.lemon@nominum.com> Charter: 6TiSCH: "IPv6 over the TSCH mode of IEEE 802.15.4e". Background/Introduction: ------------------------ Low-power and Lossy Networks (LLNs) interconnect a possibly large number of resource-constrained nodes to form a wireless mesh network. The 6LoWPAN, ROLL and CoRE IETF Working Groups have defined protocols at various layers of the protocol stack, including an IPv6 adaptation layer, a routing protocol and a web transfer protocol. This protocol stack has been used with IEEE802.15.4 low-power radios. The IEEE802.15.4e Timeslotted Channel Hopping (TSCH) is a recent amendment to the Medium Access Control (MAC) portion of the IEEE802.15.4 standard. TSCH is the emerging standard for industrial automation and process control LLNs, with a direct inheritance from WirelessHART and ISA100.11a. Defining IPv6 over TSCH, 6TiSCH is a key to enable the further adoption of IPv6 in industrial standards and the convergence of Operational Technology (OT) with Information Technology (IT). The nodes in a IEEE802.15.4e TSCH network communicate by following a Time Division Multiple Access (TDMA) schedule. A timeslot in this schedule provides a unit of bandwidth that is allocated for communication between neighbor nodes. The allocation can be programmed such that the predictable transmission pattern matches the traffic. This avoids idle listening, and extends battery lifetime for constrained nodes. Channel-hopping improves reliability in the presence of narrow-band interference and multi-path fading. These techniques enable a new range of use cases for LLNs, including: - Control loops in a wireless process control network, in which high reliability and a fully deterministic behavior are required. - Service Provider networks transporting data from different independent clients, and for which an operator needs flow isolation and traffic shaping. - Networks comprising energy harvesting nodes, which require an extremely low and predictable average power consumption. IEEE802.15.4e only defines the link-layer mechanisms. It does not define how the network communication schedule is built and matched to the traffic requirements of the network. Description of Working Group: ----------------------------- The Working Group will focus on enabling IPv6 over the TSCH mode of the IEEE802.15.4e standard. The extent of the problem space for the WG is one or more LLNs, eventually federated through a common backbone link via one or more LLN Border Routers (LBRs). Initially, the WG will limit its scope to distributed routing over a static schedule. In that case, a node's schedule can be either preconfigured, or learnt by a node when joining the network, but it remains unchanged after the node has joined a network. The Routing Protocol for LLNs (RPL) is used on the resulting network. The WG will interface with other appropriate groups in the IETF Internet, Operations and Management, Routing and Security areas. Work Items: ----------- The group will: 1. Produce "6TiSCH architecture" to describe the design of 6TiSCH networks. This document will highlight the different architectural blocks and signalling flows, including the operation of the network in the presence of multiple LBRs. Initially, the document will focus on distributed routing operation over a static TSCH schedule. 2. Produce an Information Model containing the management requirements of a 6TiSCH node. This includes describing how an entity can manage the TSCH schedule on a 6TiSCH node, and query timeslot information from that node. A data model mapping for an existing protocol (such as Concise Binary Object Representation (CBOR) over the Constrained Application Protocol (CoAP)) will be provided. 3. Produce "Minimal 6TiSCH Configuration" defining how to build a 6TiSCH network using the Routing Protocol for LLNs (RPL) and a static TSCH schedule. It is expected that RPL and the Objective Function 0 (OF0) will be reused as-is. The work will include a best practice configuration for RPL and OF0 operation over the static schedule. Based on that experience the group may produce a requirements draft for OF0 extensions, to be studied in ROLL. Non-milestone work items: ------------------------- The Working Group may maintain a number of running, often-respun documents, that evolve as the technology is refined for work items that do not affect the milestone work items: - implementers guide: this document will collect clarifying information based on input from implementers, in particular as it becomes available from interoperability events. This guide will contain information about test harnesses used for interoperability testing. - coexistence guide: this document will provide information on how 6TiSCH can be operated in an environment shared with other protocols that use the same or a similar TSCH MAC, and/or operate on the same frequency band. The WG will welcome requirements for dynamic timeslot operation, for example for centralized schedule computation. Milestones: TBD
