Technical Summary
This document specifies a mechanism that enables an RPL router to
measure the aggregated values of given routing metrics along an
existing route towards another RPL router in a low power and lossy
network, thereby allowing the router to decide if it wants to
initiate the discovery of a better route.
The mechanism described in this document can be used by an Origin in
an LLN to measure the aggregated values of some routing metrics along
a route to a Target within the LLN. The route is measured in the
direction from the Origin to the Target. Such a route could be a
source route or a hop-by-hop route established using RPL [RFC6550] or
P2P-RPL [I-D.ietf-roll-p2p-rpl]. The Origin decides what metrics to
measure and sends a Measurement Request message, carrying the desired
routing metric objects, along the route. On receiving a Measurement
Request, an Intermediate Router updates the routing metric values
inside the message and forwards it to the next hop on the route.
Thus, the Measurement Request accumulates the values of the routing
metrics for the complete route as it travels towards the Target.
Upon receiving the Measurement Request, the Target unicasts a
Measurement Reply message, carrying the accumulated values of the
routing metrics, back to the Origin. Optionally, the Origin may
allow an Intermediate Router to generate the Measurement Reply if it
already knows the relevant routing metric values along rest of the
route.
Working Group Summary:
No discontent. Once again, few comments, request for clarifications that
have all been addressed by in this revision.
Document Quality:
Yes there are several known implementations of this specification, with
interop testing:
An interoperability was carried out last month with INRIA's implementation
against Sigma Design's implementation. The report can be found:
http://hal.inria.fr/docs/00/66/16/29/PDF/RR-7864.pdf
Experiments with P2P-RPL have also taken place on the Senslab testbed
gathering boards based on MSP430 and 802.15.4 at 2.4GHz:
http://hal.archives-ouvertes.fr/docs/00/65/16/03/PDF/SOFTCOM-2011.pdf
Personnel:
The Document Shepherd is JP Vasseur (jvasseur@cisco.com)
The Responsible AD is Adrian Farrel (adrian@olddog.co.uk)