IETF-96 Proceedings

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Routing Over Low power and Lossy networks (roll) (WG)

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Routing Area Area Director(s):

Assigned Area Director


Meeting Slides:

Blue Sheets:


Request for Comments:

Charter (as of 2015-10-14):

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 characteristics:

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 specifically 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 waste.

These specific properties cause LLNs to have specific routing requirements.

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 control, fire), connected homes, health care, 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 were 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. As needed, the Working Group will liaise with the TSVWG on transport-related topics. It is expected that upper-layer applications utilizing LLNs define appropriate mechanisms. The solution must include unicast and multicast considerations.

The Working Group will document how non-control packets are routed when they cross the LLN, and when they enter and exit the LLN: the appropriate use of RH3 (RFC6553), RPI (RFC6554) and IPv6-in-IPv6 encapsulation including how routing loops are detected. In consultation with the 6lo WG, the Working Group will design a method to compress these routing headers into a single block. The WGLC on this work will be shared with 6lo.

ROLL is responsible for maintenance of the protocols that is has developed, including RPL and MPL. AD approval is required for each new work item that is proposed.

Work Items:

- Details about when to use RFC6553, RFC6554, and IPv6-in-IPv6 encapsulation.

- Details about how to compress RFC6553, RFC6554, and IP headers in the 6LoWPAN adaptation layer context