F.Y.I.: the 6tisch WG has just been rechartered, "PCE" is explicitly
mentioned.
Julien
Message transféré
Date : Fri, 4 Mar 2016 08:38:31 -0800
De : The IESG
The IPv6 over the TSCH mode of IEEE 802.15.4e (6tisch) WG in the Internet
Area of the IETF has been rechartered. For additional information, please
contact the Area Directors or the WG Chairs.
IPv6 over the TSCH mode of IEEE 802.15.4e (6tisch)
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Current status: Active WG
Chairs:
Pascal Thubert
Thomas Watteyne
Assigned Area Director:
Brian Haberman
Internet Area Directors:
Brian Haberman
Terry Manderson
Mailing list:
Address: 6ti...@ietf.org
To subscribe: https://www.ietf.org/mailman/listinfo/6tisch
Archive: https://mailarchive.ietf.org/arch/browse/6tisch/
Charter: https://datatracker.ietf.org/doc/charter-ietf-6tisch/
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 Timeslotted Channel Hopping (TSCH) mode was introduced in 2012 as an
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 IEEE802.15.4 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.
IEEE802.15.4 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
IEEE802.15.4 standard. The extent of the problem space for the WG is
one or more LLNs, possibly federated through a common backbone link
via one or more LLN Border Routers (LBRs). The WG will rely on, and if
necessary extend, existing mechanisms for authenticating LBRs.
Initially, the WG has limited its scope to distributed routing over a
static schedule using the Routing Protocol for LLNs (RPL) on the
resulting network. This new charter allows for the dynamic allocation of
cells and their exchange between adjacent peers to accommodate the
available bandwidth to the variations of throughput in IP traffic.
The WG will continue working on securing the join process and making
that fit within the constraints of high latency, low throughput and
small frame sizes that characterize IEEE802.15.4 TSCH.
Additionally, IEEE802.15.4 TSCH being a deterministic MAC, it is
envisioned that 6TiSCH will benefit from the work of DetNet WG to
establish the so-called deterministic tracks. The group will define the
objects and methods that need to be configured, and provide the
associated requirements to DetNet.
The WG will interface with other appropriate groups in the IETF
Internet, Operations and Management, Routing and Security areas.
Work Items:
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The group will:
- Produce a specification of the 6top sublayer that describes the
protocol for neighbor nodes to negotiate adding/removing cells. This
work will leverage cross participation from IEEE members including the
IEEE 6TiSCH Interest Group (IG 6T) to define protocol elements and
associated frame formats.
- Produce a specification for a default 6top Scheduling Function
including the policy to enable distributed dynamic scheduling of
timeslots for IP traffic. This may include the capability for nodes to
approp
