RTGWG P. Thubert, Ed.
Internet-Draft P. Bellagamba
Intended status: Standards Track Cisco Systems
Expires: April 5, 2013 October 2, 2012
Available Routing Constructs
draft-thubert-rtgwg-arc-00
Abstract
This draft introduces the concept of ARC, a two-edged routing
construct that forms its own fault isolation and recovery domain.
The new paradigm can be leveraged to improve the network utilization
and resiliency for unicast and multicast traffic in multiple
environments.
Requirements Language
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 RFC
2119 [RFC2119].
Status of this Memo
This Internet-Draft is submitted 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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Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
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This Internet-Draft will expire on April 5, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. ARC Set representations . . . . . . . . . . . . . . . . . . . 7
4. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 11
4.1. Load Balancing . . . . . . . . . . . . . . . . . . . . . . 11
4.1.1. Routing Hierarchies . . . . . . . . . . . . . . . . . 11
5. Lowest ARC First . . . . . . . . . . . . . . . . . . . . . . . 11
5.1. Init . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
5.2. Growing Trees . . . . . . . . . . . . . . . . . . . . . . 12
5.3. Being Safe . . . . . . . . . . . . . . . . . . . . . . . . 12
5.4. Bending An ARC . . . . . . . . . . . . . . . . . . . . . . 13
5.5. Orienting Links . . . . . . . . . . . . . . . . . . . . . 14
5.6. Looping or recursing . . . . . . . . . . . . . . . . . . . 14
6. Forwarding Along An ARC Set . . . . . . . . . . . . . . . . . 15
6.1. Control Plane Recovery . . . . . . . . . . . . . . . . . . 16
6.2. Data Plane Recovery . . . . . . . . . . . . . . . . . . . 16
7. Manageability . . . . . . . . . . . . . . . . . . . . . . . . 17
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 17
9. Security Considerations . . . . . . . . . . . . . . . . . . . 17
10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 17
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 18
11.1. Normative References . . . . . . . . . . . . . . . . . . . 18
11.2. Informative References . . . . . . . . . . . . . . . . . . 18
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 19
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1. Introduction
Traditional routing and forwarding uses the concept of path as the
basic routing paradigm to get a packet from a source to a destination
by following an ordered sequence of arrows between intermediate
nodes. In this serial design, a path is broken as soon as a single
arrow is, and getting around a breakage can require path
recomputation, network reconvergence, and incur delays to till
service is restored.
Multiple paths can be bound together for instance to form a Directed
Acyclic Graph (DAG) to a destination, but that technique can be
difficult to balance and cannot provide a full path redundancy even
in the case of a biconnected graph. For instance, if the node that
is closest to the DAG destination has only one link to that
destination, then it does not have a alternate path to get to that
destination.
It is also possible to compute an alternate routing topology for fast
rerouting to a given destination, in which case some signalling,
tagging or labelling can be put in place to indicate whether a packet
follows the normal path or was rerouted over an alternate topology.
Once a packet is rerouted, it is bound to the alternate topology so
only one breakage can be handled with looplessness guarantees in most
practical situations.
This draft introduces the concept of an Available Routing Construct
(ARC) as a routing construct made of a sequence of nodes and links
with 2 outgoing edges, so that, upon a single breakage, each lively
node in along ARC can still reach one of the outgoing edges. As a
result, an ARC is this resilient to one breakage as opposed to an
arrow that has only one outgoing edge, and an ARC topology is
resilient to one breakage per ARC.
The routing graph to reach a certain destination is expressed as a
cascade of ARCs, each ARC providing its own independent domain of
fault isolation and recovery. Unicast traffic may enter an ARC via
any node but it may only leave the ARC through one of its two edges.
One node along the ARC is designated as the cursor. In normal
unicast operations, the traffic inside an ARC flows away from the
cursor towards an edge. Upon a failure, packets may bounce on the
breakage point and flow the other way along the ARC to take the other
exit.
Aa a result an ARC is resilient to any single failure, and the
recovery can be driven either from the data plane or the control
plane. A second failure occurring within a same ARC will isolate an
ARC segment. This can be further corrected from the control plane by
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reversing all the incoming Edges in a process that might recurse till
an exit is found. When ARC reversal is applied, an ARC topology is
resilient to some cases of Shared Risk Link Group (SRLG) failures.
This draft presents the concept and provides an intuition of how ARCs
can simplify the operation and improve the network utilization and
resiliency for all sorts of traffic in multiple environments, but
defers to further documents to elaborate on the algorithms and
optimizations in the different application domains.
For instance, ARCs can also be used in datacenters for the purpose of
fast-reroute, or within a service provider network to simplify load
balancing operations or leverage optimally the ring topologies
[RFC5921]. An ARC topology can be flooded over itself and serve as a
backbone for reliable multicasting operations.
2. Terminology
The draft uses the following terminology:
ARC: Available Routing Construct. An ARC is a loopless ordered set
of nodes and links whereby traffic may enter via any node in the
ARC but may only leave the ARC through either one of the ARC
edges.
Comb: An ARC generalization: a Comb is a n-edged loopless set of
nodes and links with n >= 2; traffic may enter via any node in the
Comb but may only exit the Comb through one of its n edges. A
Comb comes with a walk operation that enables to attempt to exit
via every edge and to discover when all have been tried.
Cursor: A virtual point along an ARC that can be located on a node
or on a link between 2 nodes. In normal operations, the traffic
along the ARC flows away from its Cursor. If the cursor is a
node, then traffic can be distributed on both sides. The Cursor
may be moved to change the way traffic is load balanced along an
ARC. It may also be placed at the location of a failure to direct
traffic away from that point.
ARC Node: A Node that belongs to an ARC.
Edge ARC Node: An ARC Node at an edge of its ARC. An Edge ARC Node
is a node via wich traffic can exit the ARC.
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Edge Link: A directed link outgoing from an Edge ARC Node. Traffic
can only exit from an ARC via an Edge Link. An Edge Link does not
accept traffic into an ARC.
Intermediate ARC Node: A node that is not at an edge of an ARC. A
Intermediate ARC Node node that can receive traffic and forward
traffic between its adjacent nodes.
Intermediate Link: A link between two Intermediate ARC Nodes. An
Intermediate Link is reversible, meaning that traffic is allowed
in both directions though an individual packet is constrained in
the way its direction is reversed. For stable links such as wired
links, the typical constraint is that the direction of a packet
may be reversed at most once along a given ARC.
Collapsed ARC: An ARC that is formed of a single node. This node is
altogether the cursor and both Edge Nodes. This implies that the
node has at least 2 outgoing links to 2 different Safe Nodes.
|
|
V
C+EAN
/|\
/ | \
| V |
V V
E: Edge ARC Node -| collapsed in a single node
C: Cursor -|
Figure 1: Collapsed ARC
Infrastructure ARC: An ARC that is formed of more than one node,
which also means that the Edge Nodes are different nodes.
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| \ | |
| \ | | |
V V V |
_->IAN<---->IAN<---->IAN<---->IAN<-_ |
/ + C \ |
/ \|
V V
EAN EAN
| /|\
| / | \
| | V |
V V V
IAN: Intermediate ARC Node -|
EAN: Edge ARC Node |- All are Safe Nodes
C: Cursor -|
Figure 2: Infrastructure ARC
DAG: Directed Acyclic Graph.
ARC Set (or Cascade): A DAG with ARCs as vertices. In the DAG, an
edge between ARC A and ARC B corresponds to a link from an Edge
ARC Node in ARC A and an arbitrary ARC Node in ARC B. Note that by
definition, an ARC has at least 2 outgoing Edge Links, one per
Edge Node, and maybe more if an Edge Node has multiple outgoing
Edge Links. All vertices in the DAG have 2 forwarding solutions,
even the ARC closest to the destination.
Omega: the abstract destination (== root) of an ARC Set.
ARC Height: An arbitrary distance from Omega that is associated to
an ARC. The Height of an ARC must be more than the Height of any
of the ARCs it terminates into. The order of ARC formation by a
given algorithm can be used as a Height whereby an ARC is always
strictly higher or lower than another.
Buttressing ARC: A split ARC that is merged into another ARC at one
edge. An ARC and one or more Buttressing ARCs form a Comb
construct that is resilient to additional breakages. A
Buttressing ARC may be applied to an ARC or a Comb iff traffic
outgoing the Buttressing ARC Edge always reaches in an ARC that is
lower than this ARC, or Omega.
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| \ | |
| \ | | |
V V V |
_->IAN<---->IAN<---->IAN<---->IAN<-_----->IAN<-_
/ + C \ | \
/ \| \
V V V
EAN EAN EAN
| /|\ |
| / | \ |
| | V | |
V V V V
Figure 3: Comb with Buttressing ARC
Safe Node: A node is Safe if there is no single point of failure -
apart from the node itself - on its way to Omega. From this
definition, a node is Safe if it has at least two non-congruent
paths to two different other Safe Nodes. It results that a Safe
node that is not Omega has at least two completely disjunct paths
to Omega. When an ARC has been successfully constructed, all its
nodes become safe with respect to the Omega for which the ARC was
constructed. By extension for a collapsed path Omega is deemed to
be Safe, that is any node that pertains in Omega is a Safe Node.
?-S: A node N is deemed dependent on a node S or S-dependent
(denoted as ?-S) if S is the last single point of failure along
N's shortest path to Omega.
3. ARC Set representations
An ARC Set can be represented in a number of fashions:
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Graph View:
H2<==>H<==>H1<---I--->J1<==>J--->K1<===>K
| | | | |
| | | | |
V V V V V
D1<==>D<==>D3 E1<==>E F1<==>F<==>F2 G
| | | | | | / \
| | | | | | / \
V V V V V V V V
B1<==>B2<==>B3<==>B--->A<==>A1<------C2<==>C<==>C4
| | | |
| | | |
| V V |
+--------------------> Omega <-------------------+
Figure 4: Routing Graph View
This representation is similar to a classical routing graph with
the pecularity that some Links are marked reversible. An ARC is
represented as a sequence of reversible links. The node that
holds the cursor is also indicated somehow.
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ARC View:
+========I========+
| |
| +====J====+
| | |
+====H====+ | +=====K=====+
| | | | |
+====D====+ +====E====+ +====F====+ +====G====+
| | | | | | | |
+=========B=========+ | | +=========C=========+
| | | | | |
| +======A=======+ |
| | | |
------------------------------------------------------------------Omega
Figure 5: ARC Representation
This representation is similar to a classical routing graph with
the pecularity that some Links are marked reversible. An ARC is
represented as a sequence of reversible links.
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Collapsed DAG view:
+====+ +====+ +====+ +====+
| H | <--- | I | ---> | J | ---> | K |
| \__ | ___/ |
| \ | / |
V _| V |_ V
+====+ +====+ +====+ +====+
| D | | E | | F | <--- | G |
\ \ __/ \__ __/ \__ / /
\ \ / \ / \ / /
_| _| |_ _| |_ _| |_ |_
+====+ +====+ +====+
| B | ---> | A | <--- | C |
| | | |
V V V V
------------------------------------------------------------------Omega
Figure 6: ARC DAG
A DAG representation whereby an ARC is abstracted as a vertice and
links between ARCs are shown as directed edges. This way, the
reversible links are omitted and the graph is simplified. It can
be noted that even the vertice closest to Omega has 2 non-
congruent forwarding solutions, that is Heir Links to Omega.
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4. Applicability
This section has to be refined. ARCs probbaly apply to both unicast
and multicast and the authors expect further documents to explain how
that is done. The examples below are provided as an indication but
is not limiting the field of applications.
4.1. Load Balancing
In normal conditions, only the cursor may distribute its traffic
between the two Edge Nodes. If an Edge Node is still congested after
the cursor forwards all its traffic towards the other Edge Node, then
the cursor can be moved towards the congested Edge in order to derive
even more traffic towards the other Edge. If both Edges are
congested, then a backpressure can be applied on the incoming ARCs so
that they move their own traffic towards their own alternate Edge.
The process may recurse.
4.1.1. Routing Hierarchies
The ARC methods may be used to build and/or leverage routing
hierarchies, allowing high availability at multiple hierarchical
levels. In one hand, the view of an ARC Set can be simplified by
abstracting an ARC as a node in a DAG. The view of the routing
topology is thus simplified, as illustrated in Figure 6. In the
other hand, ARCs may be used inside a subtopology, such as a ring, to
enable forwarding inside a ring towards a next ring. Then,
abstracting a full ring as a node, ARCs can be applied to a graph of
rings, providing another level of redundancy and an abstract end to
end path computation that is represented as a cascade of ARCs of
rings.
5. Lowest ARC First
The open Lowest ARC First(oLAF) algorithm is presented below in such
a way as to help the reader figure how an ARC Set can be obtained but
not in a computer-optimized fashion that is left to be determined.
oLAF is based on Dijkstra's algorithm for Shortest Path First (SPF)
computation, and is designed in such a fashion that the reverse SPF
tree towards a destination is conserved and preferred for forwarding
along the resulting ARC Set.
We make the computation on behalf of Omega, that is an abstraction,
but could represent the node or the set of nodes that we want to
reach with an ARC Set. If Omega is instantiated as an actual
destination node, then that node may be a fine location for an ARC
Computing Engine.
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5.1. Init
So we start with an proverbial Initial Set of Nodes that are
interconnected by Links, and Omega that is the destination that we
want to reach with an ARC Set.
If there is no Heir, we're done. If there is a single Heir then the
graph is monoconnected, so we restart the computation taking that
Heir off the Set of Nodes and making it Omega.
Else, if Omega is a single Node, or if Omega is composed of multiple
nodes but we are willing to accept that both ends of an ARC terminate
in a same node in Omega, then we create virtual Omega nodes, a
minimum of two and at most one per Heir, and we make them the new
Omega. Note: we need at least two destinations because both ends of
an ARC cannot terminate in a same node.
Now we can start building an ARC Set towards the resulting Omega.
In this process, we create so-called Dependent Sets of nodes, each
owned by a Safe Node S, DSet(S). DSet(S) contains nodes that are not
determined to be Safe at the current stage of the computation and for
which S, the owner Safe Node, is the last single point of failure on
the shortest path tree to Omega. It results that a given node can be
at most in one DSet, and that a Safe Node belongs to its own DSet.
For each node S in Omega we create a DSet(S) in which we place S.
5.2. Growing Trees
And then the process goes like this:
We select the node in the Set of Nodes that is closest to Omega using
the cost towards Omega as if we were building a traditional reverse
SPF tree and we place the selected node in the same Dependent Set as
its parent in the reverse SPF tree. Note that for a Heir, the parent
might be a real node in Omega, or a virtual Omega node.
If we kept it at that, we would be building subtrees that are hanging
off a Safe Node and together would represent the reverse shortest
path tree towards Omega, each subtree being grown separately inside
DSet(S) where S is the (virtual) Safe node that is the root of the
subtree.
5.3. Being Safe
But once we have placed the selected node in a DSet, we consider its
neighbors one by one. If at least one of the neighbors is already in
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a different DSet than this node, we select the neighbor that provides
the shortest alternate path to Omega for the selected node.
Doing so, we have isolated two paths:
o one along its own shortest path that is contained within its own
Dependent Set and that leads to the owner Safe Node of this set.
o and one via the selected neighbor, along its own shortest path
within the selected neighbor's Dependent Set and that leads to the
owner Safe Node of that other set.
Because the two sets are different and have no intersection, these
paths are non-congruent. And because the two non-congruent paths
lead to two different Safe Nodes, this node is Safe.
It might happen that:
o the selected node's parent is already a Safe Node, in which case
the selected node is the Edge AN on its shortest path side.
o It might also happen that the selected neighbor is already a Safe
Node, in which case selected node is the Edge AN on its alternate
side.
If both conditions are met for a same AN, then that AN forms a
collapsed ARC by itself.
5.4. Bending An ARC
Now we form an ARC as follows:
o A height is attributed to this ARC that must be strictly more than
that of the ARCs it terminates into, if any. The order in which
the ARCs are built may be used in some cases.
o The ARC terminates in the two Safe Nodes that are the owners of
the two DSets. The normal behaviour is to make a Edge Link the
link to the Safe Node.
o If the Safe Node at one end forms a collapsed ARC by itself, it
may be absorbed in the ARC in order to build a multi-edged ARC.
o If one of the two Safe Nodes pertains in a ARC or a Comb construct
that is higher than the other end, then this ARC may be merged at
the Safe Node with its original ARC, in order to form a Comb
construct whereby this ARC is a Buttressing ARC of the Comb. The
resulting Comb conserves the height on the original ARC or Comb
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that it extends.
o The ARC is built by adjoining the two non-congruent paths that we
isolated for the selected node.
o The selected node is the node farthest from Omega in the resulting
ARC, so we make it the cursor.
o The link between the selected node and the selected neighbor would
not have been used in a classical reverse SPF tree. Here, we have
determined that this link is in fact critical to connect 2 zones
of the network (the DSets) that can act as a back up for one
another in case of the failure of their respective single points
of failure (the Safe Nodes).
o Because the ARC can be used in both directions, each AN along the
ARC has two non-congruent paths to the Safe Nodes that the ARC
terminates into. So it is a Safe Node. We create individual
DSets for each AN and we move the AN to its own DSet.
5.5. Orienting Links
For each ARC Node along the ARC:
o any link (there can be zero for a collapsed ARC, one for an Edge
AN or two of them for a Intermediate AN) between this AN and a
next AN along this ARC is made an Intermediate Link, that is,
reversible. The normal direction, away from the cursor, preserves
the shortest path.
o If this AN is an Edge AN for this ARC, than all links off this
node that terminate in a Safe Node are made Edge Links, that is,
outgoing but not reversible.
o All the other links left undertermined.
The nodes left in the Dependent Sets but the owner Safe Node are
still not Safe. They are moved back to the original Set of Nodes to
enable forming additional ARCs which might depend on this ARC in the
ARC Set.
5.6. Looping or recursing
We are done processing the particular node we had picked in the
original Set of Nodes. If the Set of Nodes as it stands now is not
empty, we continue from Section 5.2.
If the Set of Nodes went empty, we are done with this pass and we
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consider the Dependent Sets that we have put together. In a
biconnected graph, there should be one set per node and one node per
set, denoting that every node is a Safe Node.
If some portion of the graph is monoconnected, then each
monoconnected portion forms the Dependent Set of the Safe Node that
is its single point of failure. In order to be maximally redundant,
we need to form the ARCs again, within the Dependent Set.
To do so, we remove the Safe Node from the Dependent set and make it
Omega. We make the resulting DSet our Set of Nodes and run the
algorithm again.
This may recurse a number of times if the graph has monoconnected
zones within others.
6. Forwarding Along An ARC Set
Under normal conditions, the traffic flows away from the cursor of
the current ARC and cascades into the next ARC on that side of the
cursor, with the Height of the current ARC decreasing monotonically
from ARC to ARC till Omega is reached.
The same goes for a generic Comb construct. When Buttressing ARCs
are applied on a main ARC or other Buttressing ARCs, the final
construct assumes the shape of a tree. The tree may be walked in
different manners but the shortest path requires to start going down
the current ARC or Buttressing ARC to its Edge.
In case of Label forwarding, the same recursivity is applied and a
multiple ARC label path is constructed. Each ARC has is own set of
label path per Omega, each ARC Set label path being merged into the
lower ARC label set, thus at the interconnection point. At minimum,
ARC label path should be built from the cursor toward each edge, but
this would require label path recompilation upon cursor move, the
proposed approach is then to build for the normal flow to an Omega
one pair of label path from edge to edge.
As this label construct maps the ARC topology with local significant
label, the Label Distribution Protocol (LDP) could be reused to
announce label association to neighbors on the ARC.
Upon a breakage inside an ARC, until a corrective action takes place,
some traffic will be lost. The corrective action might be either
operated at the control plane or the data plane, if immediate action
and near-zero packet loss is required.
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6.1. Control Plane Recovery
Upon a first breakage in an ARC, the cursor is moved to the breakage
point, either a node or a link, so that traffic flows away from the
cursor again.
Upon a second breakage within a same ARC, a segment of the ARC is now
isolated. Both breakage points become sinks till an additional
corrective action, such as modifying the ARC Set, takes place. All
incoming links in the isolated segment are blocked , causing the
traffic to exit at the other end of the incoming ARCs.
Blocking an Edge Link in the incoming ARC may create an isolated
segment in the incoming ARC as well if it is a second breakage there
too, or if both edges of the incoming ARC tterminate in the broken
segment. In that case the process recurses and the broken zone can
be determined as the collection of the isolated segments.
If a segment of an ARC is getting isolated by a dual failure but that
ARC segment has incoming Edges then the ARC can be reversed. This
reversal is done by reversing of all the incoming Edges, which become
outgoing. The segment that was isolated now benefits from multiple
exits in a loop free fashion. This process might in turn isolate a
segment of an ARC that was incoming and the process recurses and some
links flap. If a real exit exits the process will stabilize, but a
count to infinity must be put in place to avoid a permanent flapping
when a whole ARC Subset is physically isolated. One may consider
that this process is in fact the classical link reversal technique,
as applied to the DAG of ARCs.
6.2. Data Plane Recovery
Upon a breakage inside an ARC, it is possible in the data plane to
reverse the direction of -to turn- a given packet once along the ARC
so the packets exits over the other Edge Link. But in order to avoid
loops, it is undesirable to reverse the direction of a given packet a
second time.
Note that once a given packet leaves an ARC to enter the next, it is
free to bounce again in the next ARC. In other Words, the domain
that is impacted by a turn is limited to the current ARC itself; the
ARC forms the event horizon wherein the notion that a turn happened
may cause a loop.
So a local strategy must be put in place inside an ARC to allow a
given packet to bounce once upon a breakage, and get dropped upon a
second breakage.
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In the case of IP packet forwarding, a packet can be tagged when it
bounces inside an ARC, or when it passes the cursor, for instance by
reserving a TOS bit for that purpose. When the packet bounces, the
bit is set and when the packet leaves the ARC, the bit is reset and
may be used again in the next ARC. In the generic case of a Comb, a
strategy must be put in place to walk the structure and drop a packet
that tries all the Edges. it attempts to pass the cursor twice in a
same direction, meaning that more than a full walk was already
accomplished.
In the case of MPLS forwarding, the same result can be achieved with
either 3 or 4 Labels Switched Paths (LSPs) along the ARC.
3-Labels method: In this case we lay a primary LSP from the cursoo
to the Edge in each direction, and a backup LSP Edge to Edge in
each direction. So a node along the way has three labels, one
primary and two backup, one in each direction. Should the primary
path fail, the packet can be placed along the backup LSP in the
other direction. We'll note that this method contrains the
location of the cursor. Should the cursor move, The primary LSPs
have to be recomputed, at a minimum between the old and the new
location of the cursor where the direction is reversed.
4-Labels method: In this case we have two primary and two backup
LSPs Edge to Edge in each direction. The labels are independent
of the location of the cursor, so the cursor can be moved in
control plane with no impact on labels.
7. Manageability
This specification describes a generic model. Protocols and
management will come later
8. IANA Considerations
This specification does not require IANA action.
9. Security Considerations
This specification is not found to introduce new security threat.
10. Acknowledgements
The authors wishes to thank Dirk Anteunis, Stewart Bryant, IJsbrand
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Internet-Draft ARC October 2012
Wijnands, George Swallow, Eric Osborne, Clarence Filsfils and Eric
Levy-Abegnoli for their participation and continuous support to the
work presented here.
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.
[RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing
Architecture", RFC 4291, February 2006.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007.
[RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless
Address Autoconfiguration", RFC 4862, September 2007.
11.2. Informative References
[I-D.phinney-roll-rpl-industrial-applicability]
Phinney, T., Thubert, P., and R. Assimiti, "RPL
applicability in industrial networks",
draft-phinney-roll-rpl-industrial-applicability-00 (work
in progress), October 2011.
[I-D.thubert-lowpan-backbone-router]
Thubert, P., "LoWPAN Backbone Router",
draft-thubert-lowpan-backbone-router-00 (work in
progress), November 2007.
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, November 2005.
[RFC4541] Christensen, M., Kimball, K., and F. Solensky,
"Considerations for Internet Group Management Protocol
(IGMP) and Multicast Listener Discovery (MLD) Snooping
Switches", RFC 4541, May 2006.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
[RFC5415] Calhoun, P., Montemurro, M., and D. Stanley, "Control And
Provisioning of Wireless Access Points (CAPWAP) Protocol
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Internet-Draft ARC October 2012
Specification", RFC 5415, March 2009.
[RFC5865] Baker, F., Polk, J., and M. Dolly, "A Differentiated
Services Code Point (DSCP) for Capacity-Admitted Traffic",
RFC 5865, May 2010.
[RFC5921] Bocci, M., Bryant, S., Frost, D., Levrau, L., and L.
Berger, "A Framework for MPLS in Transport Networks",
RFC 5921, July 2010.
[RFC6275] Perkins, C., Johnson, D., and J. Arkko, "Mobility Support
in IPv6", RFC 6275, July 2011.
[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.
Authors' Addresses
Pascal Thubert (editor)
Cisco Systems
Village d'Entreprises Green Side
400, Avenue de Roumanille
Batiment T3
Biot - Sophia Antipolis 06410
FRANCE
Phone: +33 497 23 26 34
Email: pthubert@cisco.com
Patrice Bellagamba
Cisco Systems
214 Avenue des fleurs
Saint-Raphael 83700
FRANCE
Phone: +33.6.1998.4346
Email: pbellaga@cisco.com
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