wdiff draft-ietf-roll-p2p-measurement-06.txt draft-ietf-roll-p2p-measurement-07.txt

Internet Engineering Task Force M. Goyal, Ed.
Internet-Draft University of Wisconsin
Intended status: Experimental Milwaukee
Expires: March 21, June 27, 2013 E. Baccelli
INRIA
A. Brandt
Sigma Designs
J. Martocci
Johnson Controls
September 17,
December 24, 2012

A Mechanism to Measure the Quality of Routing Metrics along a Point-to-point Route
in a Low Power and Lossy Network
draft-ietf-roll-p2p-measurement-06
draft-ietf-roll-p2p-measurement-07

Abstract

This document specifies a mechanism that enables an RPL router to
measure the quality 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.

Status of this Memo

This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79.

Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
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and may be updated, replaced, or obsoleted by other documents at any
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This Internet-Draft will expire on March 21, June 27, 2013.

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Table of Contents

1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4
2. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. The Measurement Object (MO) . . . . . . . . . . . . . . . . . 5
3.1. Format of the base MO . . . . . . . . . . . . . . . . . . 5 6
3.2. Secure MO . . . . . . . . . . . . . . . . . . . . . . . . 9 10
4. Originating a Measurement Request . . . . . . . . . . . . . . 9 10
4.1. To Measure When Measuring A Hop-by-hop Route with a Global
RPLInstanceID . . . . . . . . . . . . . . . . . . . . . . 10 11
4.2. To Measure When Measuring A Hop-by-hop Route with a Local
RPLInstanceID With Route Accumulation Off . . . . . . . . 12
4.3. When Measuring A Hop-by-hop Route with a Local
RPLInstanceID With Route Accumulation On . . . . . . . . . . . . . . 10
4.3. To Measure 13
4.4. When Measuring A Source Route . . . . . . . . . . . . . . . . 11 14
5. Processing a Measurement Request at an Intermediate Router Point . . 12 15
5.1. Determining Next Hop For An MO When Measuring A Source Hop-by-hop Route with a Global
RPLInstanceID . 14 . . . . . . . . . . . . . . . . . . . . . 16
5.2. Determining Next Hop For An MO When Measuring A Hop-by-hop Route with a Local
RPLInstanceID With Route Accumulation Off . . . . . . . . 17
5.3. When Measuring A Hop-by-hop Route with a Local
RPLInstanceID With Route Accumulation On . . . . . . . . . 18
5.4. When Measuring A Source Route . . . . . . . . . . . . . 14 . 19
5.5. Final Processing . . . . . . . . . . . . . . . . . . . . . 19
6. Processing a Measurement Request at the Target End Point . . . . . . 20
6.1. Generating the Measurement Reply . . . . 15 . . . . . . . . . 20
7. Processing a Measurement Reply at the Origin . . . Start Point . . . . . . 16 21
8. Security Considerations . . . . . . . . . . . . . . . . . . . 16 21
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17 23
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 23
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18 23
11.1. Normative References . . . . . . . . . . . . . . . . . . . 18 23
11.2. Informative References . . . . . . . . . . . . . . . . . . 18 24
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19 24

1. Introduction

Point to point (P2P) communication between arbitrary routers in a Low
power and Lossy Network (LLN) is a key requirement for many
applications [RFC5826][RFC5867]. RPL [RFC6550], the The IPv6 Routing Protocol for LLNs, LLNs
(RPL) [RFC6550] constrains the LLN topology to a Directed Acyclic
Graph (DAG) built to optimize the routing costs to reach the DAG's
root. The P2P routing functionality, available under RPL, has the
following key limitations:

o The P2P routes are restricted to use the DAG links only. Such P2P
routes may potentially be suboptimal and may lead to traffic
congestion near the DAG root.

o RPL is a proactive routing protocol and hence requires all P2P
routes to be established ahead of the time they are used. Many
LLN applications require the ability to establish P2P routes "on
demand".

To ameliorate situations, where the core RPL's P2P routing
functionality does not meet the application requirements,
[I-D.ietf-roll-p2p-rpl] describes P2P-RPL, an extension to core RPL.
P2P-RPL provides a reactive mechanism to discover P2P routes that
meet the specified routing constraints [RFC6551]. In some cases, the
application requirements or the LLN's topological features allow a
router to infer these routing constraints implicitly. For example,
the application may require the end-to-end loss rate and/or latency
along the route to be below certain thresholds or the LLN topology
may be such that a router can safely assume its destination to be
less than a certain number of hops away from itself.

When the existing routes are deemed unsatisfactory but the router
does not implicitly know the routing constraints to be used in P2P-
RPL route discovery, it may be necessary for the router to measure
the aggregated values of the routing metrics along the existing
route. This knowledge will allow the router to frame reasonable
routing constraints to discover a better route using P2P-RPL. For
example, if the router determines the aggregate ETX [RFC6551] along
an existing route to be "x", it can use "ETX < x*y", where y is a
certain fraction, as the routing constraint for use in P2P-RPL route
discovery. Note that it is important that the routing constraints
are not overly strict; otherwise the P2P-RPL route discovery may fail
even though a route, much better than the one currently being used,
exists.

This document specifies a mechanism that enables an RPL router to
measure the aggregated values of the routing metrics along an
existing route to another RPL router in an LLN, thereby allowing the
router to decide if it wants to discover a better route using P2P-RPL
and determine the routing constraints to be used for this purpose.
Thus, the utility of this mechanism is dependent on the existence of
P2P-RPL, which is targeting publication as an Experimental RFC. It
makes sense, therefore, for this document also to target publication
as an Experimental RFC. As more operational experience is gained
using P2P-RPL, it is hoped that the mechanism described in this
document will also be used, and feedback will be provided to the ROLL
working group on the utility and benefits of this document.

1.1. Terminology

The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in
[RFC2119].

Additionally, this

This document uses terminology from [RFC6550] and
[I-D.ietf-roll-p2p-rpl]. The following terms, originally defined in
[I-D.ietf-roll-p2p-rpl], are redefined in Additionally, this document defines the
following manner.

Origin: terms.

Start Point: The Origin Start Point refers to the RPL router that initiates
the measurement process defined in this document and is the start
point of the P2P route being measured.

Target:

End Point: The Target End Point refers to the RPL router at the end point of
the P2P route being measured.

Intermediate Router: Point: An RPL router, other than the Origin Start Point and the
Target,
End Point, on the P2P route being measured.

The following terms, already defined in [I-D.ietf-roll-p2p-rpl], have
been redefined in this document in the following manner.

Forward direction: The direction from the Start Point to the End
Point.

Backward direction: The direction from the End Point to the Start
Point.

2. Overview

The mechanism described in this document can be used by an Origin a Start Point
in an LLN to measure the aggregated values of some selected routing
metrics along a P2P route to a Target an End Point within the LLN. The route
is measured in the
direction from the Origin to the Target. Forward direction. Such a route could be a
source route Source
Route [I-D.ietf-roll-p2p-rpl] or a hop-by-hop route Hop-by-hop Route

[I-D.ietf-roll-p2p-rpl] established using RPL [RFC6550] or P2P-RPL
[I-D.ietf-roll-p2p-rpl]. Such a route could also be a "mixed" route
with the initial part consisting of hop-by-hop ascent to the root of
a non-storing DAG [RFC6550] and the final part consisting of a
source-routed descent to the End Point. The Origin Start Point 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 Point 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. End
Point. The Measurement Request may also accumulate a Source Route
that the End Point may use to reach the Start Point. Upon receiving
the Measurement Request, the Target End Point unicasts a Measurement Reply
message, carrying the accumulated values of the routing metrics, back
to the Origin. Start Point. Optionally, the Origin Start Point may allow an
Intermediate Router Point to generate the Measurement Reply if it the
Intermediate Point already knows the relevant routing metric values
along rest of the route.

3. The Measurement Object (MO)

This document defines two new RPL Control Message types, the
Measurement Object (MO), with code TBD1, and the Secure MO, with code
TBD2. An MO serves as both Measurement Request and Measurement
Reply.

3.1. Format of the base MO

0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| RPLInstanceID | Compr |T|H|A|R|B|I| SequenceNo| Num | Index |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Origin Start Point Address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
| Target End Point Address |
| |
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Address[1..Num] .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
. Metric Container Option(s) .
. .
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

Figure 1: Format of the base Measurement Object (MO)

The format of a base MO is shown in Figure 1. A base MO consists of
the following fields:

o RPLInstanceID: This field is relevant only if a hop-by-hop route
is being measured, i.e., the H flag, described subsequently, is
set to one. In this case, the Origin MUST set this field to the
RPLInstanceID of the hop-by-hop route being measured. If a source
route is being measured, the Origin MUST set this field to binary
value 10000000. An Intermediate Router MUST set specifies the RPLInstanceID
field in the outgoing MO packet to the same value that it had in
the corresponding incoming MO packet unless it is the root of a
non-storing global DAG, identified by the RPLInstanceID, Hop-
by-hop Route along which the MO packet had been traveling so far and the router
intends to insert a source route inside the Address vector to
direct Measurement Request travels (or
traveled initially until it towards the Target. In that case, the router MUST set
the RPLInstanceID field in the outgoing MO packet switched over to binary value
10000000. a Source Route).

o Compr: In many LLN deployments, IPv6 addresses share a well known,
common prefix. In such cases, the common prefix can be elided
when specifying IPv6 addresses in the Origin/Target Start Point/End Point
Address fields and the Address vector. The "Compr" field, a 4-bit
unsigned integer, is set by the Origin Start Point to specify the number
of prefix octets that are elided from the IPv6 addresses in Origin/Target Start
Point/End Point Address fields and the Address vector. An Intermediate Router
MUST set the Compr field in the outgoing MO packet to the same
value that it had in the corresponding incoming MO packet. The
Intermediate Router MUST drop the received MO message if the Compr
value specified in the message does not match what the router
considers the length of the common prefix to be. The Origin will The Start
Point will set the Compr value to zero if full IPv6 addresses are
to be carried in the Origin Address/Target Start Point Address/End Point Address fields
and the Address vector.

o Type (T): This flag is set to one if the MO represents a
Measurement Request. The flag is set to zero if the MO is a
Measurement Reply.

o Hop-by-hop (H): The Origin Start Point MUST set this flag to one if (at
least the initial part of) the route being measured is a hop-by-hop route. hop-by-hop.
In that case, the hop-by-
hop route Hop-by-hop Route is identified by the RPLInstanceID
RPLInstanceID, the End Point Address and, if the RPLInstanceID is
a local value, the Origin Address and Target Start Point Address (required to be same as the
DODAGID of the route being measured) fields inside the message. Measurement
Request. The Origin Start Point MUST set this flag to zero if the route
being measured is a source route Source Route specified in the Address vector.
An Intermediate Router Point MUST set the H flag in an outgoing MO packet
Measurement Request to the same value that it had in the
corresponding incoming MO packet Measurement Request unless the router it is the root
of the non-storing global DAG, identified by the RPLInstanceID,
along which the MO packet Measurement Request had been traveling so far and
the router Intermediate Point intends to insert a source route Source Route inside the
Address vector to direct it towards the Target. End Point. In that case,
the router Intermediate Point MUST reset set the H flag to zero in the outgoing MO packet. zero.

o Accumulate Route (A): This flag is relevant only if the MO
represents a Measurement Request that travels along a hop-by-hop
route represented by a local RPLInstanceID. In other words, this
flag MAY be set to one only if T = 1, H = 1 and the RPLInstanceID
field has a local value. Otherwise, this flag MUST be set to
zero. A value 1 in this flag indicates that the
Measurement Request MUST accumulate is accumulating a source route Source Route for use by the Target
End Point to send the Measurement Reply back to the Origin. Start Point.
Route accumulation is allowed (i.e., this flag MAY be set to one)
inside a Measurement Request only if it travels along a Hop-by-hop
Route represented by a local RPLInstanceID (i.e., H = 1,
RPLInstanceID has a local value). In this case, an Intermediate Router MUST add
Point adds its unicast IPv6 address (after eliding Compr number of
prefix octets) to the Address vector in the manner specified later. in
Section 5.3. In other cases, this flag MUST be set to zero on
transmission and ignored on reception. Route accumulation is not
allowed when the Measurement Request travels along a hop-by-hop route Hop-by-hop
Route with a global RPLInstanceID, i.e., along a global DAG,
because:

* The DAG's root may need the Address vector to insert a source
route Source
Route to the Target; End Point; and

* The Target End Point can presumably reach the Origin Start Point along this
global
DAG. DAG (identified by the RPLInstanceID field).

o Reverse (R): This flag is relevant only if the MO represents a
Measurement Request that travels along a source route, specified
in the Address vector, to the Target. In other words, this flag
MAY be set to one only if T = 1 and H = 0. Otherwise, this flag
MUST be set to zero. A value 1 in the this flag inside a Measurement Request
indicates that the Address vector contains a complete source route Source Route
from the Origin Start Point to the Target, End Point, which can be used, after
reversal, by the Target End Point to
source route send the Measurement Reply message back to
the Origin. Start Point. This flag MAY be set to one inside a Measurement
Request only if a Source Route, from the Start Point to the End
Point, is being measured. Otherwise, this flag MUST be set to
zero on transmission and ignored on reception.

o Back Request (B): This A value 1 in this flag serves as a request to
the Target End Point to send a Measurement Request towards the Origin. The Origin MAY set
this flag to one to make such a request to the Target. An
Intermediate Router MUST set the B flag in an outgoing MO packet
to the same value that it had in the corresponding incoming MO
packet. Start
Point. On receiving a Measurement Request with the B flag set to
one, the Target End Point SHOULD generate a Measurement Request to
measure the cost of its current (or the most preferred) route to
the
Origin. Start Point. Receipt of this Measurement Request would allow
the
Origin Start Point to know the cost of the back route from the Target End
Point to itself and thus determine the round-trip cost of reaching
the
Target. End Point.

o Intermediate Reply (I): Relevant only if a hop-by-hop route is
being measured, A value 1 in this flag serves as a
permission to an Intermediate Router Point to generate a Measurement
Reply if it knows the cost of the rest aggregated values of the route being measured. The Origin MAY
set this flag to one if a hop-by-hop route is routing metrics
being measured
(i.e., H = 1) and for the Origin wants to allow an Intermediate Router
to generate rest of the Measurement Reply in response to this Measurement
Request. route. Setting this flag to
one may be useful in scenarios where the Hop Count [RFC6551] is
the routing metric of interest and the Origin expects an Intermediate Router Point (e.g. the
root of a non-storing global DAG or a common ancestor of the Origin Start
Point and the Target End Point in a storing global DAG) to may know the Hop
Count of the remainder of the route to the Target. End Point. This flag MUST
MAY be set to zero one only if the route a Hop-by-hop Route with a global
RPLInstanceID is being measured is a source route (i.e., H = 0). 1, RPLInstanceID has a
global value). Otherwise, this flag MUST be set to zero on
transmission and ignored on reception.

o SequenceNo: A 6-bit sequence number, assigned by the Origin, Start Point,
that allows the Origin Start Point to uniquely identify a Measurement
Request and the corresponding Measurement Reply. An Intermediate Router MUST
set this field in the outgoing MO packet to the same value that it
had in the corresponding incoming MO packet. The Target MUST set
this field in a Measurement Reply message to the same value that
it had in the corresponding Measurement Request message.

o Num: This field indicates the number of elements, each (16 -
Compr) octets in size, inside the Address vector. If the value of
this field is zero, the Address vector is not present in the MO.

o Index: If the Measurement Request is traveling along a source
route Source
Route contained in the Address vector (T=1,H=0), (i.e., H = 0), this field
indicates the index in the Address vector of the next hop on the
route. If the Measurement Request is traveling along a hop-by-hop
route Hop-by-hop
Route with a local RPLInstanceID and the A flag Route Accumulation is set
(T=1,H=1,A=1 and on
(i.e., H = 1, RPLInstanceID field has a local value), value, A = 1), this field
indicates the index in the Address vector where an Intermediate Router
Point receiving the MO message Measurement Request must store its IPv6
address. Otherwise, this field MUST be set to zero on
transmission and ignored on reception.

o Origin Start Point Address: A unicast IPv6 address of the Origin Start Point
after eliding Compr number of prefix octets. If the MO Measurement
Request is traveling along a
hop-by-hop route Hop-by-hop Route and the
RPLInstanceID field indicates a local value, the Origin Start Point
Address field MUST specify the DODAGID value that, along with the
RPLInstanceID and the Target End Point Address, uniquely identifies the hop-by-hop route
Hop-by-hop Route being measured.

o Target End Point Address: A unicast IPv6 address of the Target End Point after
eliding Compr number of prefix octets.

o Address[1..Num]: Address[0..Num-1]: A vector of unicast IPv6 addresses (with Compr
number of prefix octets elided) representing a source route to the
Target: Source Route:

* Each element in the vector has size (16 - Compr) octets.

* The total number of elements inside the Address vector is given
by the Num field.

* When the Measurement Request is traveling along a hop-by-hop
route Hop-by-hop
Route with local RPLInstanceID and has the A flag set, set to one
(i.e., H = 1, RPLInstanceID has a local value, A = 1), the
Address vector is used to accumulate a source route to Source Route that can be
used by the Target End Point, after reversal, to send the Measurement
Reply back to the Origin.
In this case, the Start Point. The route MUST be accumulated
in the forward
direction, i.e., from the Origin to the Target. The Target
router would reverse this route to obtain a source route from
itself to Forward direction but the Origin. The IPv6 addresses in the
accumulated route MUST be reachable in the backward direction, i.e., from
the Target to the Origin. Backward direction.
An Intermediate Router Point adding its address to the Address vector
MUST ensure that its address a routing loop involving this router does not already
exist in the vector. accumulated route.

* When the Measurement Request is traveling along a source route, Source Route
(i.e., H = 0), the Address vector MUST contain a complete route
to the Target End Point and the IPv6 addresses in the Address vector
MUST be reachable in the forward direction, i.e., from the Origin to the Target. Forward direction. A router (Origin (the
Start Point or an Intermediate Router) Point) inserting an Address
vector inside an MO a Measurement Request MUST ensure that no address
appears more than once inside the vector. Each router on the
way MUST ensure that the loops do a routing loop involving this router does
not exist within the source route. Source Route. The Origin Start Point MAY set the
R flag in the MO Measurement Request if the route in the Address
vector represents a complete route from the Origin Start Point to the Target
End Point and this route can be used after reversal by the
Target End Point, after
reversal, to send the Measurement Reply message back to the Origin
Start Point (i.e., the IPv6 addresses in the Address vector are
reachable in the backward direction - from the Target to the Origin). Backward direction).

* The Origin Start Point and Target End Point addresses MUST NOT be included in
the Address vector.

* The Address vector MUST NOT contain any multicast addresses.

o Metric Container Options: An MO A Measurement Request MUST contain one
or more Metric Container options [RFC6550] to accumulate the routing metric
values of the selected routing metrics in the manner described in
[RFC6551] for the route being measured.

3.2. Secure MO

A Secure MO message follows the format

Section 4 describes how does a Start Point set various fields inside
a Measurement Request in Figure 7 of different cases. Section 5 describes how
does an Intermediate Point process a received Measurement Request
before forwarding it further. Section 6 describes how does the End
Point process a received Measurement Request and generate a
Measurement Reply. Finally, Section 7 describes how does the Start
Point process a received Measurement Reply.

3.2. Secure MO

A Secure MO follows the format in Figure 7 of [RFC6550], where the
base format is the base MO shown in Figure 1.

4. Originating a Measurement Request

If an Origin needs to measure

A Start Point sets various fields inside the routing metric values along a P2P
route towards a Target, Measurement Request it
generates an MO message and sets its
fields as described in Section 3.1. The setting of MO fields in
specific cases is the manner described below. In all cases, the Origin MUST set
the T flag to one to indicate that the MO represents a Measurement
Request. The Origin Start Point MUST also
include the routing metric objects [RFC6551] of interest inside one
or more Metric Container options inside the MO.
Depending on the metrics being measured, the Origin must also
initiate these routing metric objects by including the values of the
routing metrics for the first hop on the P2P route being measured.

After setting the MO fields appropriately, the Origin Measurement Request. The
Start Point then determines the next hop on the P2P route being measured.
If a hop-by-hop Hop-by-hop route is being measured (i.e., the H flag is set to one), = 1), the next hop
is determined using the RPLInstanceID, the Target End Point Address and, if
RPLInstanceID is a local value, the Origin Start Point Address fields in the MO.
Measurement Request. If a source route Source Route is being measured (i.e., the H flag is set to
zero), =
0), the Address[1] Address[0] element inside the Measurement Request contains
the next hop address. The Origin Start Point MUST discard the MO message Measurement
Request if:

o the next hop address is not a unicast address; or

o the next hop is not on-link; or

o the next hop is not in the same RPL routing domain as the Origin. Start
Point.

Otherwise, depending on the routing metrics, the Start Point must
initiate the routing metric objects inside the Metric Container
options by including the routing metric values for the first hop on
the route being measured. Finally, the Origin Start Point MUST unicast the MO message
Measurement Request to the next hop on the P2P route. route being measured.

4.1. To Measure When Measuring A Hop-by-hop Route with a Global RPLInstanceID

If a hop-by-hop route Hop-by-hop Route with a global RPLInstanceID is being measured, measured
(i.e., H = 1, RPLInstanceID has a global value), the MO message MUST NOT
contain the an Address vector and the following various MO fields MUST be set in the manner specified below:
following manner:

o RPLInstanceID: MUST be set to the RPLInstanceID of the route being
measured.

o Compr: MUST be set to specify the number of prefix octets that are
elided from the IPv6 addresses in Start Point/End Point Address
fields.

o Type (T): MUST be set to one since the MO represents a Measurement
Request.

o Hop-by-hop (H): This flag MUST be set to one.

o Accumulate Route (A): This flag MUST be set to zero.

o Reverse (R): This flag MUST be set to zero.

o Back Request (B): This flag MAY be set to one to request the End
Point to send a Measurement Request to the Start Point.

o Intermediate Reply (I): This flag MAY be set to one if the Start
Point expects an Intermediate Point to know the values of the
routing metrics being measured for the remainder of the route.

o SequenceNo: Assigned by the Start Point so that it can uniquely
identify the Measurement Request and the corresponding Measurement
Reply.

o Num: This field MUST be set to zero.

o Index: This field MUST be set to zero.

o Start Point Address: MUST be set to a unicast IPv6 address of the
Start Point after eliding Compr number of prefix octets.

o End Point Address: MUST be set to a unicast IPv6 address of the
End Point after eliding Compr number of prefix octets.

4.2. To Measure When Measuring A Hop-by-hop Route with a Local RPLInstanceID With
Route Accumulation Off

If a hop-by-hop route Hop-by-hop Route with a local RPLInstanceID is being measured
and the MO is Start Point does not accumulating want the MO to accumulate a source route Source Route
for the Target's End Point's use, the MO message MUST NOT contain the Address vector
and the following various MO fields MUST be set in the manner specified below: following manner:

o RPLInstanceID: MUST be set to the RPLInstanceID of the route being
measured.

o Compr: MUST be set to specify the number of prefix octets that are
elided from the IPv6 addresses in Start Point/End Point Address
fields.

o Type (T): MUST be set to one since the MO represents a Measurement
Request.

o Hop-by-hop (H): This flag MUST be set to one.

o Accumulate Route (A): This flag MUST be set to zero.

o Reverse (R): This flag MUST be set to zero.

o Num: Back Request (B): This field flag MAY be set to one to request the End
Point to send a Measurement Request to the Start Point.

o Intermediate Reply (I): This flag MUST be set to zero.

o SequenceNo: Assigned by the Start Point so that it can uniquely
identify the Measurement Request and the corresponding Measurement
Reply.

o Num: This field MUST be set to zero.

o Index: This field MUST be set to zero.

o Origin Start Point Address: This field MUST contain the DODAGID value
(after eliding Compr number of prefix octets) associated with the
route being measured.

o End Point Address: MUST be set to a unicast IPv6 address of the
End Point after eliding Compr number of prefix octets.

4.3. When Measuring A Hop-by-hop Route with a Local RPLInstanceID With
Route Accumulation On

If a hop-by-hop route Hop-by-hop Route with a local RPLInstanceID is being measured
and the Origin Start Point desires the MO to accumulate a source route Source Route for
the
Target End Point to send the Measurement Reply message back, it the MO MUST
contain an Address vector and various MO fields MUST be set in the
following MO fields manner:

o RPLInstanceID: MUST be set to the RPLInstanceID of the route being
measured.

o Compr: MUST be set to specify the number of prefix octets that are
elided from the IPv6 addresses in Start Point/End Point Address
fields and the manner specified below: Address vector.

o Type (T): MUST be set to one since the MO represents a Measurement
Request.

o Hop-by-hop (H): This flag MUST be set to one.

o Accumulate Route (A): This flag MUST be set to one.

o Reverse (R): This flag MUST be set to zero.

o Intermediate Reply (I): Back Request (B): This flag MUST MAY be set to zero.

o Address vector: The Address vector must be large enough one to
accomodate a complete source route from request the Origin End
Point to send a Measurement Request to the Target.
All the bits in the Address vector field Start Point.

o Intermediate Reply (I): This flag MUST be set to zero.

o SequenceNo: Assigned by the Start Point so that it can uniquely
identify the Measurement Request and the corresponding Measurement
Reply.

o Num: This field MUST specify the number of address elements elements, each
(16 - Compr) octets in size, that can fit inside the Address
vector.

o Index: This field MUST be set to one.

o Origin Address: This field MUST contain zero to indicate the DODAGID value (after
eliding Compr number of position in
the Address vector where the next hop must store its IPv6 address.

o Start Point Address: This field MUST contain the DODAGID value
(after eliding Compr number of prefix octets) associated with the
route being measured.

4.3. To Measure

o End Point Address: MUST be set to a unicast IPv6 address of the
End Point after eliding Compr number of prefix octets.

o Address vector: The Address vector must be large enough to
accomodate a complete Source Route from the End Point to the Start
Point. All the bits in the Address vector field MUST be set to
zero.

4.4. When Measuring A Source Route

If a source route Source Route is being measured, the Origin Start Point MUST set the
following various
MO fields in the manner specified below: following manner:

o RPLInstanceID: MUST be set to the binary value 10000000.

o Compr: MUST be set to specify the number of prefix octets that are
elided from the IPv6 addresses in Start Point/End Point Address
fields and the Address vector.

o Type (T): MUST be set to one since the MO represents a Measurement
Request.

o Hop-by-hop (H): This flag MUST be set to zero.

o Accumulate Route (A): This flag MUST be set to zero.

o Reverse (R): This flag SHOULD be set to one if the source route Source Route in
the Address vector can be reversed and used by the Target End Point to
source route
send the Measurement Reply message back to the Origin. Start Point.
Otherwise, this flag MUST be set to zero.

o Back Request (B): This flag MAY be set to one to request the End
Point to send a Measurement Request to the Start Point.

o Intermediate Reply (I): This flag MUST be set to zero.

o Address vector:

* The Address vector MUST contain a complete route from the
Origin to SequenceNo: Assigned by the Target (excluding Start Point so that it can uniquely
identify the Origin Measurement Request and the Target).

* The IPv6 addresses (with Compr prefix corresponding Measurement
Reply.

o Num: This field MUST specify the number of address elements, each
(16 - Compr) octets elided) in size, inside the Address vector vector.

o Index: This field MUST be reachable set to zero to indicate the position in
the forward direction,
i.e., from Address vector of the Origin to next hop on the Target.

* route.

o Start Point Address: MUST be set to a unicast IPv6 address of the
Start Point after eliding Compr number of prefix octets.

o End Point Address: MUST be set to a unicast IPv6 address of the
End Point after eliding Compr number of prefix octets.

o Address vector:

* The Address vector MUST contain a complete Source Route from
the Start Point to the End Point (excluding the Start Point and
the End Point).

* The IPv6 addresses (with Compr prefix octets elided) in the
Address vector MUST be reachable in the Forward direction.

* If the R flag is set to one, the IPv6 addresses (with Compr
prefix octets elided) in the Address vector MUST also be
reachable in the backward direction, i.e., from the Target to
the Origin. Backward direction.

* To prevent avoid loops in the source route, Source Route, the Origin Start Point MUST ensure
compliance to the following rules:

+ Any IPv6 address MUST NOT appear more than once in the
Address vector.

+ If the Address vector includes multiple IPv6 addresses
assigned to the Origin's Start Point's interfaces, such addresses
MUST appear back to back inside the Address vector.

* Each address appearing in the Address vector MUST be a unicast
address.

o Num: This field MUST be set to indicate the number of elements in
the Address vector.

o Index: This field MUST be set to one.

5. Processing a Measurement Request at an Intermediate Router Point

A router (an Intermediate Router Point or the Target) End Point) MAY discard a
received MO with no processing to meet any policy-related goal. Such
policy goals may include the need to reduce the router's CPU load or
to enhance its battery life. life or to prevent misuse of this mechanism by
unauthorized nodes.

A router MUST discard a received MO with no further processing if the
value in the Compr field inside the received message is not same as more than
what the router considers the length of the common prefix used in
IPv6 addresses in the LLN to be.

On receiving an MO, if a router chooses to process the packet
further, it MUST check if one of its IPv6 addresses is listed as
either the Origin Start Point or the Target End Point Address. If neither, the
router considers itself an Intermediate Router Point and MUST process the
received MO in the following manner.

An Intermediate Router Point MUST discard the packet with no further
processing if the received MO is not a Measurement Request.

If the H and I flags are set to one in the received MO and Request (i.e., T =
0).

Next, the Intermediate Router knows Point determines the values type of the routing metrics,
specified in the Metric Container, for route being
measured (by checking the remainder values of the route, it
MAY generate a Measurement Reply on H flag and the Target's behalf RPLInstanceID
field) and processes the received MO accordingly in the manner
specified in Section 6 (after including in the Measurement Reply the
relevant routing metric values for the complete route next.

5.1. When Measuring A Hop-by-hop Route with a Global RPLInstanceID

If a Hop-by-hop Route with a global RPLInstanceID is being
measured). Otherwise, measured
(i.e. H = 1 and RPLInstanceID has a global value), the Intermediate Router
Point MUST process the received MO Measurement Request in the following
manner.

The router Intermediate Point MUST determine discard the next received Measurement Request
with no further processing if the Num field is not set to zero or if
the Address vector is present in the received message.

If the Intermediate Reply (I) flag is set to one in the received
Measurement Request and the Intermediate Point knows the values of
the routing metrics, specified in the Metric Container options, for
the remainder of the route, it MAY generate a Measurement Reply on
the End Point's behalf in the manner specified in Section 6.1 (after
including in the Measurement Reply the relevant routing metric values
for the complete route being measured). Otherwise, the Intermediate
Point MUST process the received message in the following manner.

The Intermediate Point MUST then determine the next hop on the P2P route
being measured using the RPLInstanceID and the End Point Address. If
the Intermediate Point is the root of the non-storing global DAG
along which the received Measurement Request had been traveling so
far, it MUST process the received Measurement Request in the manner described below.
following manner:

o The router MUST drop discard the MO Measurement Request with no further
processing and MAY send an ICMPv6 Destination Unreachable (with
Code 0 - No Route To Destination) error message to the source of the message Start Point
if it can does not determine the next hop for
the message. The router MUST drop know how to reach the MO with no further processing: End Point.

o If Otherwise, unless the next hop address is not a unicast address; or

o If router determines the next hop is not on-link; or

o If End Point itself to be
the next hop is not in the same RPL routing domain as the
router.

Next, hop, the router MUST update make the routing metric objects, contained following changes in the Metric Container option(s) inside the MO, either by updating the
aggregated value for
received Measurement Request:

* Set the routing metric or by attaching H, A, R and I flags to zero (the A and R flags should
already be zero in the local
values for received message).

* Leave remaining fields unchanged (the Num field would be
modified in next steps). Note that the metric inside RPLInstanceID field
identifies the object. An Intermediate Router can
only update non-storing global DAG along which the existing metric objects and
Measurement Request traveled so far. This information MUST NOT add any new
routing metric object be
preserved so that the End Point may use this DAG to send the Metric Container. An Intermediate
Router MUST drop
Measurement Reply back to the MO if it cannot update Start Point.

* Insert a routing metric object
specified new Address vector inside the Metric Container.

After updating the routing metrics, the router MUST unicast the MO to
the next hop.

5.1. Determining Next Hop For An MO Measuring A Measurement Request and
specify a Source Route

In case to the received MO is measuring End Point inside the Address
vector as per the following rules:

+ The Address vector MUST contain a source complete route (H=0),

o The from the
router MUST verify that to the Address[Index] element lists one
of its unicast IPv6 addresses, failing which End Point (excluding the router MUST
discard and the MO packet with no further processing;

o End
Point);

+ The router MUST then increment IPv6 addresses (with Compr prefix octets elided) in the Index field and use
Address vector MUST be reachable in the
Address[Index] element as Forward direction;

+ To avoid loops in the next hop. If Index is greater than
Num, Source Route, the router MUST use the Target Address as the next hop.

To prevent loops, an Intermediate Router ensure
that

- Any IPv6 address MUST discard NOT appear more than once in the MO packet
with no further processing if
Address vector;

- If the Address vector includes multiple IPv6 addresses
assigned to the router's interfaces and if interfaces, such addresses do not MUST
appear back to back inside the Address vector.

5.2. Determining Next Hop For An MO Measuring A Hop-by-hop Route

+ Each address appearing in the received MO is measuring Address vector MUST be a hop-by-hop route (H=1),
unicast address.

* Specify in the router
MUST use Num field the RPLInstanceID, number of address elements in the Target
Address and, if RPLInstanceID
is a local value, vector.

* Set the Origin Address Index field to determine zero to indicate the position in the
Address vector of the next hop for on the MO. Moreover,

o If route. Thus, Address[0]
element contains the RPLInstanceID address of the hop-by-hop route is a local value and
the A flag is set, next hop on the router route.

The Intermediate Point MUST check if then complete the Address vector
already contains one processing of its IPv6 addresses. If yes, the router
MUST discard the packet
received Measurement Request as specified in Section 5.5.

5.2. When Measuring A Hop-by-hop Route with no further processing. Otherwise,
the router MUST store one of its IPv6 addresses (after eliding
Compr prefix octets) at location Address[Index] and then increment
the Index field.

o a Local RPLInstanceID With
Route Accumulation Off

If the router a Hop-by-hop Route with a local RPLInstanceID is being measured
and the root of route accumulation is off (i.e., H = 1, RPLInstanceID has a
local value, A = 0), the non-storing global DAG along
which Intermediate Point MUST process the received MO message had been traveling so far,

*
Measurement Request in the following manner.

The router discards Intermediate Point MUST discard the MO packet received Measurement Request
with no further processing if
it does not know of a source route to reach the Target
(specified by Num field is not zero or if the Target
Address listed vector is present in the packet).

* Otherwise, the router received message.

The Intermediate Point MUST do then determine the following:

+ Set next hop on the route
being measured using the RPLInstanceID, the End Point Address and the
Start Point Address (which represents the DODAGID of the route being
measured). The Intermediate Point MUST discard the Measurement
Request with no further processing and MAY send an ICMPv6 Destination
Unreachable (with Code 0 - No Route To Destination) error message to
the Start Point if it can not determine the next hop. Otherwise, the
Intermediate Point MUST complete the processing of the received
Measurement Request as specified in Section 5.5.

5.3. When Measuring A Hop-by-hop Route with a Local RPLInstanceID With
Route Accumulation On

If a Hop-by-hop Route with a local RPLInstanceID is being measured
and the route accumulation in on (i.e., H = 1, RPLInstanceID has a
local value, A = 1), the Intermediate Point MUST process the received
Measurement Request in the following manner.

The Intermediate Point MUST discard the received Measurement Request
with no further processing if the Num field is set to zero or if the
Address vector is not present in the received message.

The Intermediate Point MUST then determine the next hop on the route
being measured using the RPLInstanceID, the End Point Address and the
Start Point Address (which represents the DODAGID of the route being
measured). The Intermediate Point MUST discard the Measurement
Request with no further processing and MAY send an ICMPv6 Destination
Unreachable (with Code 0 - No Route To Destination) error message to
the Start Point if it can not determine the next hop. The
Intermediate Point MUST drop the received Measurement Request with no
further processing if the index field has value Num - 1 and the next
hop is not same as the End Point. In this case, the next hop would
have no space left in the Address vector to store its address.

Otherwise, the Intermediate Point MUST check if adding one of its
IPv6 addresses to the the Address vector would create a routing loop
in the accumulated route. If yes, the router MUST discard the packet
with no further processing. Otherwise, the router MUST store one of
its unicast IPv6 addresses (after eliding Compr prefix octets) at
location Address[Index] and then increment the Index field. The IPv6
address added to the Address vector MUST be reachable in the Backward
direction.

The Intermediate Point MUST then complete the processing of the
received Measurement Request as specified in Section 5.5.

5.4. When Measuring A Source Route

If a Source Route is being measured (i.e., H = 0), the Intermediate
Point MUST process the received Measurement Request in the following
manner.

The Intermediate Point MUST discard the received Measurement Request
with no further processing if the Num field is set to zero or if the
Address vector is not present in the received message.

The Intermediate Point MUST then determine the next hop on the H, A and R flags to zero and route
being measured in the manner described below. The Intermediate Point
MUST verify that the Address[Index] element lists one of its unicast
IPv6 addresses, failing which it MUST discard the Measurement Request
with no further processing. To prevent loops, the Intermediate Point
MUST discard the Measurement Request with no further processing if
the RPLInstanceID field
to binary value 10000000.

+ Remove any existing Address vector includes multiple IPv6 addresses assigned to its
interfaces and if such addresses do not appear back to back inside
the MO.

+ Insert a new Address vector inside vector. The Intermediate Point MUST then increment the MO
Index field and specify a
source route to use the Target inside Address[Index] element as the next hop
(unless Index value is now Num). If the Index value is now Num, the
Intermediate Point MUST use the End Point Address vector as per the following rules:

- next hop.

The Address vector Intermediate Point MUST contain a then complete route from the
router to processing of the Target (excluding
received Measurement Request as specified in Section 5.5.

5.5. Final Processing

The Intermediate Point MUST drop the router and received Measurement Request
with no further processing:

o If the
Target);

- The IPv6 addresses (with Compr prefix octets elided) next hop address is not a unicast address; or

o If the next hop is not on-link; or

o If the next hop is not in the Address vector same RPL routing domain as the
Intermediate Point.

Next, the Intermediate Point MUST be reachable in update the routing metric objects,
inside the Metric Container option(s) inside the Measurement Request,
either by updating the aggregated value for the routing metric or by
attaching the forward
direction, i.e., towards local values for the Target;

- To prevent loops in metric inside the source route, object. An
Intermediate Point can only update the router MUST
ensure that

o Any IPv6 address existing metric objects and
MUST NOT appear more than once in the
Address vector;

o If the Address vector includes multiple IPv6 addresses
assigned add any new routing metric object to the router's interfaces, such addresses Metric Container.
An Intermediate Point MUST appear back to back drop the Measurement Request with no
further processing if it cannot update a routing metric object
specified inside the Address vector.

- Each address appearing in Metric Container.

Finally, the Address vector Intermediate Point MUST be a unicast address.

+ Specify in the Num field the number of address elements in
the Address vector.

+ Set the Index field Measurement Request
to one. the next hop.

6. Processing a Measurement Request at the Target End Point

On receiving an MO, if a router chooses to process the packet message
further and finds one of its unicast IPv6 addresses listed as the Target
Address, End
Point Address, the router considers itself the End Point and MUST
process the received MO in the following manner.

The End Point MUST discard the received message with no further
processing if it is not a Measurement Request (i.e., T = 0).

If the received Measurement Request traveled on a Hop-by-hop Route
with a local RPLInstanceID with route accumulation on (i.e., H = 1,
RPLInstanceID has a local value and A = 1), elements Address[0]
through Address[Index - 1] in the Address vector contain a complete
Source Route from the Start Point to the End Point (excluding the
Start Point and the End Point), which the End Point MAY use, after
reversal, to reach the Start Point.

If the received Measurement Request traveled on a Source Route and
the Reverse flag is set to one (i.e., H = 0, R = 1), elements
Address[0] through Address[Num - 1] in the Address vector contain a
complete Source Route from the router considers itself Start Point to the Target and MUST process End Point
(excluding the
received MO in Start Point and the following manner.

The Target MUST discard End Point), which the packet with no further processing if End Point
MAY use, after reversal, to reach the
received MO is not a Measurement Request. Start Point.

The Target End Point MUST update the routing metric objects in the Metric
Container options if required and MAY note the measured values for
the complete route (especially, if the received Measurement Request
is likely a response to an earlier Measurement Request that the
Target End
Point had sent to the Origin Start Point with B flag set to one).

The Target End Point MUST generate a Measurement Reply message. message as specified
in Section 6.1. If the B flag is set to one in the received
Measurement Request, the End Point SHOULD generate a new Measurement
Request to measure the cost of its current (or the most preferred)
route to the Start Point. The routing metrics used in the new
Measurement Request MUST include the routing metrics specified in the
received Measurement Request.

6.1. Generating the Measurement Reply

A Measurement Reply MUST have the Type (T) flag set to zero and need
not contain the Address vector. The following fields inside a
Measurement Reply message MUST have the same SequenceNo field values as they had inside the
received
corresponding Measurement Request message. Request: RPLInstanceID, Compr, SequenceNo,
Start Point Address, End Point Address and Metric Container
Option(s). The remaining fields inside a Measurement Reply may have
any value and MUST be ignored on reception at the Start Point. The
received Measurement Request message can be MAY trivially be converted into the a
Measurement Reply by setting the T Type (T) flag to zero. The Target MAY remove the Address
vector from the

A Measurement Reply if desired. The Target MUST then be unicast the Measurement Reply back to the Origin: Start Point:

o If the Measurement Request traveled along a global DAG (i.e., one
with a global RPLInstanceID), DAG, identified
by the RPLInstanceID field, the Measurement Reply MAY be unicast
back to the Origin Start Point along the same DAG.

o If the Measurement Request traveled along a hop-by-hop route Hop-by-hop Route with
a local RPLInstanceID and accumulated a Source Route from the A flag inside the received message
is set
Start Point to one, the Target End Point, this Source Route MAY reverse the source route contained
in the Address vector and use it be used after
reversal to send the Measurement Reply back to the Origin. Start Point.

o If the Measurement Request traveled along a source route Source Route and the R
flag inside the received message is set to one, the Target End Point MAY
reverse the source route Source Route contained in the Address vector and use
it to send the Measurement Reply back to the Origin.

If the B flag in the received Measurement Request is set to one, the
Target SHOULD generate a new Measurement Request to measure the cost
of its current (or the most preferred) route to the Origin. The
routing metrics used in the new Measurement Request MUST include the
routing metrics specified in the received Measurement Request. Start Point.

7. Processing a Measurement Reply at the Origin Start Point

When a router receives an MO, it examines if one of its unicast IPv6
addresses is listed as the Origin Start Point Address. If yes, the router
is the
Origin Start Point and MUST process the received message in the
following manner.

The Origin Start Point MUST discard the packet with no further processing if
the received MO is not a Measurement Reply or if the Origin Start Point has
no recollection of sending a Measurement Request with the sequence
number listed in the received MO. corresponding Measurement Request.

The Origin MUST examine Start Point can use the routing metric objects inside the Metric
Container options to evaluate the quality of metrics for the measured P2P route. If a
routing metric object contains local metric values recorded by
routers on the route, the Origin MUST aggregate Start Point can make use of these local
values by aggregating them into an end-to-end value as per metric according to the
aggregation rules for the specific metric. A Start Point is then
free to interpret the metrics for the route according to its local
policy.

8. Security Considerations

The mechanism defined in this document can potentially be used by a
compromised router to generate send bogus Measurement Requests to arbitrary Target routers.
End Points. Such Measurement Requests may cause CPU overload in the
routers in the network, drain their batteries and cause traffic
congestion in the network. Note that some of these problems would
occur even if the compromised router were to generate bogus data
traffic to arbitrary destinations.

Since a Measurement Request can travel along a source route Source Route specified
in the Address vector, some of the security concerns that led to the
deprecation of Type 0 routing header [RFC5095] may be valid here. To
address such concerns, the mechanism described in this document
includes several remedies:

o This document requires that a route inserted inside the Address
vector must be a strict source route Source Route and must not include any
multicast addresses.

o This document requires that an MO message must not cross the
boundaries of the RPL routing domain where it originated. A
router must not forward a received MO message further if the next
hop belongs to a different RPL routing domain. Hence, any
security problems associated with the mechanism would be limited
to one RPL routing domain.

o This document requires that a router must drop a received MO
message if the next hop address is not on-link or if it is not a
unicast address.

o This document requires that a router must check the source route Source Route
inside the Address vector of each received MO message to ensure
that it does not contain a loop involving the router. The router
must drop the received packet if the source route Source Route does contain
such a loop. This and the previous two rules protect the network
against some of the security concerns even if a compromised node
inserts a malformed Address vector inside the MO message.

The measurement mechanism described in this document may potentially
be used by a rogue node to find out key information about the LLN,
e.g., the topological features of the LLN (such as the identity of
the key nodes in the topology) or the remaining energy levels
[RFC6551] in the LLN routers. This information can potentially be
used to attack the LLN. To protect against such misuse, this
document allows RPL routers implementing this mechanism to not
process MO messages (or process such messages selectively) based on a
local policy. Further, an LLN deployment may use Secure MO
Section 3.2 messages to invoke RPL-provided security mechanisms and
prevent misuse of the measurement mechanism by unauthorized nodes.

9. IANA Considerations

This document defines two new RPL messages:

o "Measurement Object" (see Section 3.1), assigned a value TBD1 from
the "RPL Control Codes" space [to be removed upon publication:
http://www.iana.org/assignments/rpl/rpl.xml#control-codes]
[RFC6550]. IANA is requested to allocate TBD1 from the range
0x00-0x7F to indicate a message without security enabled. The
string TBD1 in this document should be replaced by the allocated
value. These last two sentences should be removed before
publication.

o "Secure Measurement Object" (see Section 3.2), assigned a value
TBD2 from the "RPL Control Codes" space [to be removed upon
publication:
http://www.iana.org/assignments/rpl/rpl.xml#control-codes]
[RFC6550]. IANA is requested to allocate TBD2 from the range
0x80-0xFF to indicate a message with security enabled. The string
TBD2 in this document should be replaced by the allocated value.
These last two sentences should be removed before publication.

+------+---------------------------+---------------+
| Code | Description | Reference |
+------+---------------------------+---------------+
| TBD1 | Measurement Object | This document |
| TBD2 | Secure Measurement Object | This document |
+------+---------------------------+---------------+

RPL Control Codes

10. Acknowledgements

Authors gratefully acknowledge the contributions of Matthias Philipp,
Pascal Thubert, Richard Kelsey and Zach Shelby in the development of
this document.

11. References

11.1. Normative References

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

11.2. Informative References

[I-D.ietf-roll-p2p-rpl]
Goyal, M., Baccelli, E., Philipp, M., Brandt, A., and J.
Martocci, "Reactive Discovery of Point-to-Point Routes in
Low Power and Lossy Networks", draft-ietf-roll-p2p-rpl-13 draft-ietf-roll-p2p-rpl-15
(work in progress), June December 2012.

[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.

11.2. Informative References

[RFC5095] Abley, J., Savola, P., and G. Neville-Neil, "Deprecation
of Type 0 Routing Headers in IPv6", RFC 5095,
December 2007.

[RFC5826] Brandt, A., Buron, J., and G. Porcu, "Home Automation
Routing Requirements in Low-Power and Lossy Networks",
RFC 5826, April 2010.

[RFC5867] Martocci, J., De Mil, P., Riou, N., and W. Vermeylen,
"Building Automation Routing Requirements in Low-Power and
Lossy Networks", RFC 5867, June 2010.

[RFC6550] Winter, T., Thubert, P., Brandt, A., Hui, J., Kelsey, R.,
Levis, P., Pister, K., Struik, R., Vasseur, JP., and R.
Alexander, "RPL: IPv6 Routing Protocol for Low-Power and
Lossy Networks", RFC 6550, March 2012.

[RFC6551] Vasseur, JP., Kim, M., Pister, K., Dejean, N., and D.
Barthel, "Routing Metrics Used for Path Calculation in
Low-Power and Lossy Networks", RFC 6551, March 2012.

Authors' Addresses

Mukul Goyal (editor)
University of Wisconsin Milwaukee
3200 N Cramer St
Milwaukee, WI 53211
USA

Phone: +1 414 2295001
Email: mukul@uwm.edu

Emmanuel Baccelli
INRIA

Phone: +33-169-335-511
Email: Emmanuel.Baccelli@inria.fr
URI: http://www.emmanuelbaccelli.org/
Anders Brandt
Sigma Designs
Emdrupvej 26A, 1.
Copenhagen, Dk-2100
Denmark

Phone: +45 29609501
Email: abr@sdesigns.dk

Jerald Martocci
Johnson Controls
507 E Michigan Street
Milwaukee 53202
USA

Phone: +1 414 524 4010
Email: jerald.p.martocci@jci.com