Luxbg fringe

The wireless fringe
Uni.lu, December 2012

Pascal Thubert (Cisco Systems)

Wireless: the evolution trait

Cheap multipoint access
New types of devices (Internet Of Things)
New usages (X-automation, Mobile Internet)

Cheap Install
Deploying wire is slow and costly

Global Coverage
From Near Field to Satellite via 3/4G
Everywhere copper/fiber cannot reach

Uni.lu © 2012 Cisco and/or its affiliates. All rights reserved. Unclassified 2

Agenda

The Fringe of the Internet
The Route-Over Fringe
The Mesh-Under Fringe
The Overlay Fringe
The RPL Fringe protocol


The Fringe of the Internet

BRKEWN-3012 © 2010 Cisco and/or its affiliates. All rights reserved. Unclassified 4

The routing Infrastructure today

 The Internet
Fully engineered
Hierarchical, Aggregations, ASs, Wire links
Fully distributed States
Shows limits (BGP tables, addr. depletion)

Reached adult size,
mature to aging

 Intranets
Same structure as the Internet
Yet decoupled from the Internet
NAT, Socks, Proxies

First model for Internet extension


The emerging Fringe of the Internet
L2 mesh Under
A Multi-hop Public Access Points,
4 Proprietary mission specific products
3
2 Edge
1 L3 Route Over
Migration to IETF Protocols (RPL)
NEMO Internet of Things (IOT)
B’s Machine to Machine (M2M)
A’s
Home Home
Mobile Overlays
Fixed wired Global reachability
Infrastructure Route Projection

5 MANET
Mesh 6 The Fringe DOES NOT LEAK
7
8 into the
B C Routing Infrastructure


The Route-Over Fringe


Swarming

! IPv6

IPv6

Mobile Router
SOS

Emergency
HotSpot IPv6

(roadside)
Mobile Router


Sensor Dust

“Sensor dust” spread over a territory
Sensors assume a fixed arbitrary
geographical distribution
Numerous sensors with limited
capabilities (battery …)
A limited number of relays (MR)
MRs run an SGP (RPL)
2 to 3 uplinks (MR with backhaul
capability)


Fleet

Global motion plus relative
mobility TLMR

Managed hierarchy over
dynamic topology
Secured uplink to base
Dark Zone coverage and
range extension (nesting)


Nested NEMO Route optimization
HA1 CN1
CN2

HA2

CN

Internet
MR1
HA

HA1: HA of MR1 VMN
HA2: HA of MR2
HA-VMN: HA of VMN
CR: Correspondent Router MR2

Forming the nested NEMO

 Attachment selection fixed vs Mobile Internet
Router
 Preventing loops in nested NEMO
topology
 Optimize Default Route selection,
shallow trees/DAGs
 Fast reconfiguration upon
movements

Potential attachment
Based on RA reception


MANEMO

 Couple IPv6 global mobility with RPL
Mobility from NEMO, LISP, other… Internet
 Minimum set of rules for all MRs
Attach whenever possible
Generic RPL loop avoidance
Delay Attachment by target depth

 Individual attachment
May use different OF
Common metrics

 Ordered Default Router List
for fast switching / recovery
MONAMI -> Instances
Default route
Kept in DRL
Dropped


The Mesh-Under Fringe


Monitoring and Automation
Healthcare

Energy Defense
Efficiency
Asset
Predictive maintenance tracking

Agriculture

Car 2 Car Research & Discovery
Industrial Automation
Intelligent Building
Smart Grid
Smart Cities
Smart
Home


ISA100: Wireless Systems
for Industrial Automation

ISA100.11a industrial WSN
Wireless systems for industrial automation
Process control and related applications

Leverages 802.15.4 + IPv6
Link Local Join process
Global Address runtime
6LoWPAN Header Compression
Yet specific routing and ND
Next: Backbone Router

ISA100.15 backhaul


ISA100.11 / ISA100.15 reference model

ISA100.15 ISA100.11a
Backhaul Backbone
Router Router

Internet

Gateway
(ALG)

Plant
network
System
Security
Manager
Manager

What’s a Backbone Router?

 Common ND based abstraction over a
backbone
 Scales DAD operations (distributes
6LoWPAN ND LBR)
 Scales the subnetwork (high speed
backbone)
 Allows interaction with nodes on the
backbone or in other subnets running
different operations

http://tools.ietf.org/html/draft-thubert-6lowpan-backbone-router


The RPL (pronounced ripple)
Fringe Protocol


Routing With RPL

New Radios issues: Addressed in RPL ?
Dynamic Topologies

Peer selection

Constrained Objects

Fuzzy Links

Routing, local Mobility

Global Mobility


RPL key concepts

Minimum topological awareness

Data Path validation

Non-Equal Cost Multipath Fwd

Instantiation per constraints/metrics

Autonomic Subnet G/W Protocol

Optimized Diffusion over NBMA


Controlling the control … by design

Distance Vector vs. Link State
Knowledge of SubDAG addresses and children links
Lesser topology awareness => lesser sensitivity to change
No database Synchronization => Adapted to movement
Optimized for Edge operation
Optimized for P2MP / MP2P, stretch for arbitrary P2P
Least Overhead Routing Approach via common ancestor
Proactive vs. Reactive
Actually both with so-called P2P draft
Datapath validation


Datapath Validation
Control Information in Data Packets:

Instance ID
Hop-By-Hop Header Sender Rank
Direction (UP/Down)

Errors detected if:

- No route further down for packet going down
- No route for packet going down
- Rank and direction do not match


Directed Acyclic Graph for NECM

In the context of routing, a DAG is formed by a collection
of vertices (nodes) and edges (links), each edge connecting one node
to another (directed) in such a way that it is not possible to start at Node
X and follow a directed path that cycles back to Node X (acyclic).


Generic Rank-based Loop Avoidance

1) A root has a Rank of 1. A
router has a Rank that is higher
than that of its DAG parents. 4) But the Router MUST NOT move
down its DAG
2) A Router that is no more – but under controlled limits
attached to a DAG MUST poison whereby the router is allowed a
its routes, either by advertising limited excursion down
an INFINITE_RANK or by
forming a floating DAG. 5) A Router MAY jump from its
current DAG into any different
3) A Router that is already part DAG at any time and whatever
of a DAG MAY move at the Rank it reaches there,
any time in order to get closer unless it has been a member of
to the root of its current DAG the new DAG in which case rule
in order to reduce its own Rank 4) applies


Global versus Local Repair

 : : A new DODAG iteration
Rebuild the DAG … Then repaint the prefixes upon changes
A new Sequence number generated by the root
A router forwards to a parent or as a host over next iteration

 : find a “quick” local repair path
Only requiring local changes !
May not be optimal according to the OF
Moving UP and Jumping are cool.
Moving Down is risky: Count to Infinity Control


Objective Function

Extend the generic behavior
For a specific need / use case

Used in parent selection
Contraints
Policies Position in the DAG
Metrics

Computes the Rank increment
Based on hop metrics
Do NOT use OF0 for adhoc radios!
(OF 0 uses traditional weighted hop count)


For Your
Routing Metrics in LLNs Reference

Node Metrics Link Metrics

Node State and Attributes Object Throughput Object
Purpose is to reflects node workload (CPU, Currently available throughput (Bytes per
Memory…) second)
“O” flag signals overload of resource Throughput range supported
“A” flag signal node can act as traffic
aggregator
Node Energy Object Latency
“T” flag: Node type: 0 = Mains, 1 = Battery, 2 = Can be used as a metric or constraint
Scavenger Constraint - max latency allowable on path
“I” bit: Use node type as a constraint Metric - additive metric updated along path
(include/exclude)
“E” flag: Estimated energy remaining
Hop Count Object Link Reliability
Can be used as a metric or constraint Link Quality Level Reliability (LQL)
Constraint - max number of hops that can be 0=Unknown, 1=High, 2=Medium, 3=Low
traversed Expected Transmission Count (ETX)
Metric - total number of hops traversed (Average number of TX to deliver a
packet)
Link Colour
Metric or constraint, arbitrary admin value


Simulation Results For Your
Reference

Traffic Control

Traffic Holes – Global Repair only

Routing Table
Sizes


Example radio connecticity

Reachability imposed
by L2 radio
Variable, almost per
packet links


Example radio connecticity

At a given point of
time connectivity is
(fuzzy)

Radio link


Applying RPL
0
1 Clusterhead
2
1
1st pass (DIO) 2
1

Establishes a logical DAG topology 3
2

2
Trickle Subnet/config Info 3 2

Sets default route 3
4 2
Self forming / self healing 4
4
3
5
2nd pass (DAO)
3
paints with addresses and prefixes 6 4

Any to any reachability 5
5
But forwarding over DAG only
saturates upper links of the DAG
And does not use the full mesh properly Potential link

Link selected as parent link


Multiple DODAGs within Instance
0
1 Clusterhead
A second root is available 2
1 1
(within the same instance) 2 0
2
The DAG is partitioned 3
2
3 2
1 root = 1 DODAG
3

1 Node belongs to 1 DODAG 4 2

3
(at most, per instance) 3
3
Nodes may JUMP 4

from one DODAG to the next 5
5
3

Nodes may MOVE 6
44 5

up the DODAG 4

Going Down MAY cause loops
May be done under CTI control Potential link

Link selected and oriented by DIO


Multiple Instances

0
Clusterhead
Running as Ships-in-the- 2
1

1
night 2
1

2
3
1 instance = 1 DAG 2
3 2

A DAG implements 4
3
2
constraints 3
3
3
Serving different 4

Objective Functions A 5 4
3

Using different metrics 4

Forwarding along a
DODAG (like a vlan) Potential link Constrained instance

Default instance


Applying ARCs
ARC scoped Advertisements 0
Clusterhead
SubDAG via its root 2
1

1
1
Adv Scope == ARC 2
2
Normal DIO up. 3
2
3 2

3
4 2
Now forwarding over DAG 3

AND ARCs 3
3
4
Reduces congestions of
3
upper links of the DAG 5 4

Still LORA for P2P 4

Potential link IGP subarea (bidirectional)

Link selected and oriented by TD


Summary

New Radios issues: Addressed in RPL by:
Dynamic Topologies DV, ORA P2MP/MP2P, LORA P2P

Peer selection Objective Functions, Metrics

Constrained Objects Controlling the control

Fuzzy Links NECM Directed Acyclic Graphs
Trickle and Datapath validation

Routing, local Mobility Local and Global Recovery

Global Mobility N/A


Next steps…

 Reactive model (already started, aka P2P)
 PCE (ala TSMP/ISA100.11a/WiHART)
 DAG limitations
Sibling routing
Other resilient schemes (ARCs)

 Stimulated updates (lookup)
 Asymmetrical links
 Multi-Topology routing and cascading


“We might be at the eve of pervasive networking, a vision
for the Internet where every person and every device is
connected to the network in the ultimate realization of
Metcalf's Law.”

IoT6 © 2012 Cisco and/or its affiliates. All rights reserved. Unclassified 38

BACKUP Material


The Radio Enabler


Wireless: the evolution trait

Cheap multipoint access
New types of devices (Internet Of Things)
New usages (X-automation, Mobile Internet)

Cheap Install
Deploying wire is slow and costly

Global Coverage
From Near Field to Satellite via 3/4G
Everywhere copper/fiber cannot reach


Dynamic topologies

No preexisting physical topology
Can be computed by a mesh under
protocol, but…
Else Routing must infer its topology

Movement
natural and unescapable
Yet difficult to predict or detect


Peer selection

Potentially Large Peer Set
Metrics (e.g. RSSI, ETX…)
Highly Variable Capabilities L3 Reachability (::/0, …)
Constraints (Power …)
Selection Per Objective


Constrained Objects

 Smart object are usually
Small & Numerous
« sensor Dust »

 Battery is critical
Deep Sleep
Limited memory
Small CPU

 Savings are REQUIRED
Control plane
Data plane (Compression)


Fuzzy links

Neither transit nor P2P
More like a changing NBMA
a new paradigm for routing

Changing metrics
(tons of them!)
(but no classical cost!)

Inefficient flooding
Self interfering

QoS and CAC


Local Routing & Mobility
Stretch vs. Control
Non Equal Cost multipath
Optimize table sizes and updates
Directed Acyclic Graphs (DAG) a MUST
Optimized Routing Approach (ORA) vs
Maybe also, Sibling routing
Least Overhead Routing Approach (LORA)
on-demand routes (reactive)

Objective Routing
Forwarding and retries
Weighted Hop Count the wrong metric
Same vs. Different next hop
Instances per constraints and metrics
Validation of the Routing plane


Global Mobility
Pervasive Access
Satellite
3/4G coverage
802.11, 802.15.4

Always Reachable
at a same identifier
Preserving connections
Or not ? (CORE*, DTN**)

Fast roaming
Within technology (L2)
Between Technologies (L3)

* Constrained RESTful Environments

** Delay-Tolerant Networking


What’s missing

 A radio abstraction
802.21, L2 triggers, OmniRAN
Roaming within and between technologies

 A subnet model
NBMA, interference awareness
Federation via backbone / backhaul

 Broadcast and look up optimization
Large scale
non-aggregatable
numbering and naming schemes


Why IPv6 ?


Why IP ?

Open Standards vs. proprietary
COTS* suppliers drive costs down but
Reliability, Availability and Security up

IP abstraction vs. per MAC/App
802.11, 802.15.4 (e), Sat, 3G, UWB
Keep L2 topology simple

To Infinity and Beyond… But End-to-End.
No intermediate gateway, tunnel, middle boxes & other trick

* Commercial, off-the-shelf


Which IP version ?

The current Internet comprises
several billion devices
Smart Objects will add tens of
billions of additional devices
IPv6 is the only viable way forward

Tens of
Things Billions
Smart Objects

Mobile 2~4 Billions
Phones & cars
IPv4 Unallocated pool to exhausted March 2011 !
Fixed 1~2 Billions RIRs pools to exhaust late 2011 and through 2012

PCs & servers

Protocol Evolution
Little work on adapting IPv4 to radios
Rather adapt radios to IPv4 e.g. WIFI
infrastructure mode
« Classical » IPv6
Large, Scoped and Stateful addresses
Neighbor Discovery, RAs (L3 beacons)
SLAAC (quick and scalable)
Anycast Addresses
IPv6 evolution meets Wireless:

NEMO (Mobile Routers) (Proxy) MIPv6
6LoWPAN ROLL/RPL
ISA100.11a ZigBee/IP


IPv6 addresses and headers

Stateful (states local and remote addresses)
Simple IPv6 Header
Extension Headers
Compressible
(6LoWPAN)


6LoWPAN Neighbor Discovery

Proactive Registration to
the default Router (aka
6LoWPAN Router, 6LR)

Default Router DADs
with an Edge Router
(aka 6LBR, B for Border)

ND proxy over a classic
ND backbone by
Backbone Router
(overloading 6LBR)


RPL: a 2-pass Routing Protocol for
Low power and Lossy Networks (LLN)

1: DAG Information
Organize a routing topology
Distribute subnet information
Default route UP

2: Destination Advertisement
Advertise and install routes down
To prefixes, addresses and mcast
group

Low control overhead
rapid convergence time
Or Energy conservation


NEMO & Global HAHA

Enables a subnet to change
its point of attachment to the
Internet
Packets to the mobile subnet
are forwarded by a Home
Agent over a dynamic tunnel
Nodes attached to MR are
unaware of the mobility
Global HAHA:
a global scalable model
See Also, LISP; HIP; PMIP…

IPv6 still lacks
 NBMA / ML subnet
IPv6 only supports P2P and transit (ethernet)
By nature, a radio network is NBMA
 L3 « VLAN »
So far only available with MPLS
Early attempts (MTR, RPL instances)
 L4/5 hints
Flow Label given away to fwd plane
 Microflows / compound flows
In WSN, a flow has multiple sources
 Local and Global IP Mobility Unification
(eg MANEMO)


ISA100 and IETF

 Introduced at ISA100, discussed at IETF

 Split from the 6LoWPAN ND spec
WG decision (Hiroshima)

 Added registration from RPL

 No duplicate unique ID detection
As discussed on the list, too complex


Registration (2nd step one second later)
---+------------------------
| The BR maintains
+-----+ a state and a route
| | Router / ALGateway to the WSN node
| | for the registration
+-----+
lifetime
|
| Transit Link
+--------------------+------------------+
NA(O) | NA(O) | |
+-----+ (root) +-----+ (6LBR) +-----+
| | router | | router | | router
Host
+-----+ Host
+-----+ +-----+
Routeo DAO Routeo o DAC
o o o
In RIB o o ack
o o o o In RIB o o
o o o o o o
o o o o o o o o o o
o o o o o o o


Binding Tracking Option

 Used to resolve conflicts
 Need In ND: TID to detect movement
 Need In RPL: Object Unique ID for DAD
+ DAO-ACK (DUPLICATE) flow

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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Type | Length | TID |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| reserved |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| |
+ Owner Unique Identifier +
| |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+


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