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Routing Over Low power and Lossy networks

The information below is for an older approved charter
Document Charter Routing Over Low power and Lossy networks WG (roll) Snapshot
Title Routing Over Low power and Lossy networks
Last updated 2015-04-04
State Approved
WG State Active
IESG Responsible AD John Scudder
Charter edit AD Alvaro Retana
Send notices to "Rene Struik" <>, "Michael Richardson" <>, "Alvaro Retana" <>, "Ines Robles" <>


Low power and Lossy networks (LLNs) are made up of many
embedded devices with limited power, memory, and processing
resources. They are interconnected by a variety of links, such as
IEEE 802.15.4, Bluetooth, Low Power WiFi, wired or other low
power PLC (Powerline Communication) links. LLNs are transitioning
to an end-to-end IP-based solution to avoid the problem of
non-interoperable networks interconnected by protocol translation
gateways and proxies.

Generally speaking, LLNs have at least five distinguishing
- LLNs operate with a hard, very small bound on state.
- In most cases, LLN optimize for saving energy.
- Typical traffic patterns are not simply unicast flows (e.g. in some
cases most if not all traffic can be point to multipoint).
- In most cases, LLNs will be employed over link layers with
restricted frame-sizes, thus a routing protocol for LLNs should be
adapted for such link layers.
- LLN routing protocols have to be very careful when trading off
efficiency for generality; many LLN nodes do not have resources to

These specific properties cause LLNs to have specific routing

Existing routing protocols such as OSPF, IS-IS, AODV, and OLSR have
been evaluated by the working group and have in their current form been
found to not satisfy all of these specific routing requirements.

The Working Group is focused on routing issues for LLN.

There is a wide scope of application areas for LLNs, including
industrial monitoring, building automation (HVAC, lighting, access
fire), connected homes, healthcare, environmental monitoring, urban sensor
networks (e.g. Smart Grid), asset tracking. The Working Group focuses
on routing solutions for a subset of these: industrial, connected
home, building and urban sensor networks for which routing requirements have
been specified. These application-specific routing requirement
documents will be used for protocol design.

The Working Group focuses only on IPv6 routing architectural framework
for these application scenarios. The Framework will take into
consideration various aspects including high reliability in the presence
of time
varying loss characteristics and connectivity while permitting low-power
operation with very modest memory and CPU pressure in networks
potentially comprising
a very large number (several thousands) of nodes.

The Working Group will pay particular attention to routing security
and manageability (e.g., self routing configuration) issues. It will
also need to consider the transport characteristic the routing protocol
messages will experience. Mechanisms that protect an LLN from congestion
collapse or
that establish some degree of fairness between concurrent
communication sessions are out of scope of the Working Group. It is
expected that
upper-layer applications utilizing LLNs define appropriate mechanisms.
The solution must include unicast and multicast considerations.

Work Items:

  • Specification of routing metrics used in path calculation. This
    includes static and dynamic link/node attributes required for routing in

  • Provide an architectural framework for routing and path selection at
    Layer 3 (Routing for LLN Architecture) that addresses such issues as
    whether LLN routing require a distributed and/or centralized path
    computation models, whether additional hierarchy is necessary and how it

Manageability will be considered with each approach, along with
various trade-offs for maintaining low power operation, including the
presence of non-trivial loss and networks with a very large number of nodes.

  • Produce a routing security framework for routing in LLNs.

  • Protocol work: The Working Group will consider specific routing
    requirements from the four application documents collectively, and
    specify either
    a new protocol or extend an existing routing protocol in cooperation
    with the
    relevant Working Group.
    If requirements from the four target application areas cannot be met
    with a single protocol, the WG may choose to specify or extend more than
    protocol (this will require a recharter of the WG).

  • Documentation of applicability statement of ROLL routing protocols.