3 hours course on IEEE and IETF protocols introducing the 6TiSCH architecture and the RPL routing protocol. Course given at telecom Bretagne on Feb 12th 2014

1. • Telecom Bretagne, February 2014
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Pascal Thubert
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1

2. Challenge: harness
innovation
• More efficient operations
• New and/or improved experience
Shaking up the
competitive landscape
• Between small and large entities
• Leveraging IT, data and analytics
http://internetofeverything.cisco.com/explore
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2

3. 1000*scale => No leak in the Internet
=> Opaque Fringe operations
Reachability
=> Radio
Addressing => IPv6
Density
=> spatial
reuse
=> Routing
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4. The Fringe of the Internet
LLNs
IEEE 802.15.4
IEEE 802.15.4e TSCH
6TiSCH
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5. Routing IP in LLNs
Routing over radios
RPL concepts
Applying RPL
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6. The Fringe of
the
Internet
BRKEWN-3012
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Unclassified
6

7. • The Internet
•
Fully engineered
• Hierarchical, Aggregations, ASs, Wire links
•
Fully distributed States
• Shows limits (BGP tables, addr. depletion)
Reached adult size, mature to aging
Conceptually unchanged by IPv6
• IPv4 Intranets
Same structure as the Internet
• Yet decoupled from the Internet
•
• NAT, Socks, Proxies
First model for Internet extension
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8. L2 mesh Under
A
Multi-hop Public Access Points,
Proprietary mission specific products
Address the scale issue at L2/ND
4
3
2
Edge
1
L3 Route Over
Migration to IETF Protocols (RPL)
Internet of Things (IOT, M2M)
Different IPv6 (6LoWPAN, SDN)
NEMO
A‟s
Home
B‟s
Home
Mobile Overlays
Global reachability
Route Projection
Network virtualization
Fixed wired
Infrastructure
5
Mesh
6
7
8
B
C
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MANET
The Fringe DOES NOT LEAK
into the
Routing Infrastructure
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9. Low Power Lossy
Networks
9

10. New level of cost effectiveness
Deploying wire is slow and costly
Low incremental cost per device
Reaching farther out
New types of devices (Internet Of Things)
New usages (widespread monitoring, IoE)
Global Coverage from Near Field to Satellite via 3/4G
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11. • LLNs comprise a large number of highly
constrained devices (smart objects)
interconnected by predominantly wireless links of
unpredictable quality
• LLNs cover a wide scope of applications
• Industrial Monitoring, Building Automation,
Connected Home, Healthcare, Environmental
Monitoring, Urban Sensor Networks, Energy
Management, Asset Tracking, Refrigeration
• Several IETF working groups and Industry
Alliance addressing LLNs
• IETF - CoRE, 6Lowpan, ROLL
• Alliances - IP for Smart Objects Alliance (IPSO)
World‟s smallest web server
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12. • LLNs operate with a hard, very small bound on state
• LLNs are optimised for saving energy in the majority of
cases
• Traffic patterns can be MP2P, P2P and P2MP flows
• Typically LLNs deployed over link layers with restricted
frame-sizes
• Minimise the time a packet is enroute (in the air/on the wire) hence
the small frame size
• The routing protocol for LLNs should be adapted for such links
• LLN routing protocols must consider efficiency versus
generality
• LLN nodes are typically very conservative in resources
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13. IEEE 802.15.4
13

14. Initial activities focused on wearable
devices “Personal Area Networks”
Activities have proven to be much more
diverse and varied
•Data rates from Kb/s to
Gb/s
•Ranges from tens of metres
up to a Kilometre
•Frequencies from MHz to THz
•Various applications not
necessarily IP based
Focus is on “specialty”, typically short
range,
communications
•If it is wireless and not a
LAN, MAN, RAN, or WAN, it
http://www.ieee802.org/15/pub/TG4.html is
IEEE 802.15to be Task Group 4 (TG4) Charter
likely WPAN™ 802.15 (PAN)
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The only IEEE 802 Working Group with
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15. 802.15.4
Amendments
802.11 Wireless
LAN
WiFi
802.11a/b/g/n/ah
802.15 Personal
Area Network
802.15.1
Bluetooth
802.15.4c
PHY for China
802.15.2
Co-existence
802.15.4d
PHY for Japan
802.15.3
High Rate WPAN
802.15.4e
MAC
Enhancements
802.15.4
Low Rate WPAN
802.15.4f
PHY for RFID
802.15.5
Mesh Networking
802.15.4g
Smart Utility Networks
802.15.6 Body Area
Networking
TV White Space PHY
15.4 Study Group
IEEE 802
LAN/MAN
802.16 Wireless
Broadband Access
802.22 Wireless
Regional Area Network
802.15.7 Visible
Light
Communications
© 2013-2014 Cisco and/or its affiliates. All rights reserved.
TSCH
• Industrial strength
• Minimised listening
costs
• Improved security
• Improved link
reliability
• Support smart-grid
networks
• Up to 1 Km
transmission
• >100Kbps
• Millions of fixed
endpoints
• Outdoor use
• Larger frame size
• PHY Amendment
• Neighborhood Area
Networks
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16. • Designed for low bandwidth, low transmit power, small frame size
•
More limited than other WPAN technologies such as Bluetooth
•
Basic packet size is 127 bytes (802.15.4g is up to 2047 bytes) (Smaller packets, less errors)
•
Transmission Range varies (802.15.4g is up to 1km)
• Fully acknowledged protocol for transfer reliability
• Data rates of 851, 250, 100, 40 and 20 kbps (IEEE 802.15.4-2011 05-Sep-2011)
•
Frequency and coding dependent
• Two addressing modes; 16-bit short (local allocation) and 64-bit IEEE (unique global)
• Several frequency bands (Different PHYs)
•
Europe 868-868.8 MHz – 3 chans , USA 902-928 MHz – 30 chans, World 2400-2483.5 MHz – 16 chans
•
China - 314–316 MHz, 430–434 MHz, and 779–787 MHz Japan - 920 MHz
• Security Modes: None, ACL only, Secured Mode (using AES-CCM mode)
• 802.15.4e multiple modes including Time Synchronized Channel Hopping (TSCH)
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17. • Specifies PHY and MAC only
• Medium Access Control Sub-Layer (MAC)
• Responsible for reliable communication between two devices
• Data framing and validation of RX frames
• Device addressing
• Channel access management
• Device association/disassociation
• Sending ACK frames
• Physical Layer (PHY)
• Provides bit stream air transmission
• Activation/Deactivation of radio transceiver
• Frequency channel tuning
• Carrier sensing
• Received signal strength indication (RSSI)
• Link Quality Indicator (LQI)
• Data coding and modulation, Error correction
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Upper Layers
(Network &
App)
MAC Layer
(MAC)
Physical Layer
(PHY)
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18. R
F
R
P
• Full Function Device (FFD)
R
F
• Can operate as a PAN co-ordinator (allocates local
addresses, gateway to other PANs)
• Can communicate with any other device (FFD or
RFD)
• Ability to relay messages (PAN co-ordinator)
• Reduced Function Device (RFD)
• Very simple device, modest resource requirements
• Can only communicate with FFD
• Intended for extremely simple applications
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19. Operates at Layer 2
• Star Topology
• Mesh Topology
R
F
F
R
R
R
F
P
• All devices
communicate to PAN
co-ordinator which uses
mains power
• Other devices can be
battery/scavenger
R
R
P
F
F
• Cluster Tree
F
R
F
F
R
F
P
F
R
• Devices can
communicate directly if
within range
R
F
R
R
• Higher layer protocols
like RPL may create
their own topology that
do not follow 802.15.4
topologies
Single PAN co-ordinator exists for all topologies
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20. IEEE 802.15.4e
TimeSlotted
Channel Hopping
20

21. • Better process optimization and more accurate
predictive maintenance increase profit; 1%
improvement in a refinery with a $1.5B annual
profit leads to $40k/day ($15M/yr) more profit
• Thus more and different sensors can be justified
economically, if they can be connected
• But wire buried in conduit has a high installation
and maintenance cost, with long lead times to
change, and is difficult to repair
• The solution: wireless sensors in non-critical
applications, designed for the industrial
environment: temperature, corrosion, intrinsic
safety, lack of power sources (particularly when
there is no wire)
• For critical control loops, use wireless control room
links with controllers located in the field, possibly
connected over local wiring
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22. Converging ICT and OT
Operational technology (OT) is hardware and
software that detects or causes a change through
the direct monitoring and/or control of physical
devices, processes and events in the enterprise.
Convergence of IT and OT technologies, aka the Industrial Internet,
represents a multibillion opportunity for IT vendors and long term job
creation.
Deterministic Wireless Networking is one of the key elements.
For each „critical‟ wired measurement there are hundreds missing
ones that could be addressed through wireless (Industrial Internet)
Architecture and Standards are necessary for Industry adoption
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23. Industrial connected device growth
WWAN: GSM – LTE
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WLAN: 802.11 WPAN: 802.15.4, ISA100.11a, WirelessHART
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24. ISA100: Wireless Systems
for Industrial Automation
ISA100.11a industrial WSN
• Wireless systems for industrial automation
• Process control and related applications
Leverages 802.15.4(e) + IPv6
• Link Local Join process
• Global Address runtime
• 6LoWPAN Header Compression
• Yet specific routing and ND
• Next: Backbone Router
ISA100.15 backhaul
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25. IEEE 802.15.4e

Amendment to the 802.15.4-2006 MAC needed for the applications
served by

802.15.4f PHY Amendment for Active RFID
 802.15.4g PHY Amendment for Smart Utility Networks
 initially for Industrial applications

(such as those addressed by wiHART and the ISA100.11a standards)

Security: support for secured ack

Low Energy MAC extension


Channel Hopping


Coordinated Sampled Listening (CSL)
Not built-in, subject to vendor design. Open std work started with 6TSCH
New Frame Types

Enhanced (secure) Acknowledgement (EACK)
 Enhanced Beacon and Beacon Request (EB and EBR)
 Optional Information Elements (IE)
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26. Channel Hopping :
• retry around interference,
• round robin strategy
Time Slotted (or Synchronized) :
•
•
•
•
Deterministic: Synchronized + Time formatted in SlotFrame(s)
Tracks: below IP, can be orchestrated by a third party like virtual circuits
Slotted: benefits of slotted aloha vs. aloha => reduce collisions
Battery operation: if traffic profile is known, devices wake upon need
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27. Reliability through (all possible!)
Code diversity
Spatial diversity
Code Division Multiplex Access
Dynamic Power Control
Network Coding (WIP)
DAG routing topology + ARCs
Frequency diversity
Duo/Bi-casting (live-live)
Channel hopping
B/W listing
Time Diversity
ARQ + FEC (HARQ)
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28. • Schedule => direct trade-off between throughput, latency and
power consumption.
• A collision-free communication schedule is typical in industrial
applications.
• IEEE802.15.4e published April 2012.
A
B
16 channel offsets
C
E
D
F
G
e.g. 31 time slots (310ms)
I
H
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J
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29. 29

30. Why IPv6 ?
Going IP
BRKEWN-3012
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Unclassified
30

31. 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
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32. 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
IPv4 Unallocated pool exhausted March 2011 !
RIPE NCC: Sept 2012; ARIN March 2015 (last /8)
Things
Mobile
Fixed
© 2013-2014 Cisco and/or its affiliates. All rights reserved.
Tens of
Billions
Smart Objects
2~4 Billions
Phones & cars
1~2 Billions
PCs & servers
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33. Application
Core
Constrained Restful
Environments
Charter to provide a framework for resourceoriented applications intended to run on
constrained IP networks.
General
6lo
IPv6 over the TSCH mode of 802.15.4e
Internet
6TiSCH
Initial charter to produce an architecture, a
minimal RPL operation over a static schedule
and a data model to control the LLC (6top)
Lightweight Implementation Guidance
Ops and Mgmt
LWIG
Routing
IETF
ROLL
Charter is to provide guidance in building
minimal yet interoperable IP-capable devices for
the most constrained environments. .
Routing over Low Power Lossy
Networks
Charter focusses on routing issues for low power
lossy networks.
Security
Reuse work done here where possible
Transport
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34. Requirement for a new standard
• Industrial requires standard-based products
• Must support equivalent features as incumbent
protocols
• Must provide added value to justify migration
• 6TiSCH value proposition
• Design for same time-sensitive MAC (802.15.4e TSCH)
• Direct IPv6 access to device (common network mgt)
• RPL Distributed routing for scalability (for monitoring)
• Large scale IPv6 subnet for mobility (50K +)
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35. Active IETF WG, 4 WG docs being adopted
Define an Architecture that links it all together
Align existing standards
• (RPL, 6LoWPAN, PANA?, RSVP, PCEP, MPLS)
over 802.15.4e TSCH
Support Mix of centralized and distributed
deterministic routing
Design 6top sublayer for L3 interactions
Open source implementations (openWSN…)
Multiple companies and universities participating
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36. Management
and Setup
Discovery
Pub/Sub
Centralized
route and track
computation
and installation
Authentication
for Network
Access
Wireless ND
(NPD proxy)
PCEP/PCC
CoAP/DTLS
TCP
Distributed
Distributed
route and track
route and track
computation
computation
and installation
and installation
AAA 6LoWPAN ND RPL
UDP
ICMP
Time Slot
scheduling
and track
G-MPLS
forwarding
RSVP
IPv6
6LoWPAN HC
6top
IEEE 802.15.4e TSCH
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}
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37. CoAP
CoAP
CoAP
CoAP
UDP
UDP
UDP
UDP
IPv6
IPv6
IPv6
IPv6
6LoWPAN-HC
6LoWPAN-HC
6LoWPAN-HC
6LoWPAN-HC
6top
6top
6top
6top
15.4e TSCH
15.4e TSCH
15.4e TSCH
15.4e TSCH
15.4 PHY
15.4 PHY
15.4 PHY
15.4 PHY
A
X
Y
U
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38. CoAP
CoAP
CoAP
CoAP
UDP
UDP
UDP
UDP
IPv6
IPv6
IPv6
IPv6
6LoWPAN-HC
6LoWPAN-HC
6LoWPAN-HC
6LoWPAN-HC
6top
6top
6top
6top
15.4e TSCH
15.4e TSCH
15.4e TSCH
15.4e TSCH
15.4 PHY
15.4 PHY
15.4 PHY
15.4 PHY
A
© 2013-2014 Cisco and/or its affiliates. All rights reserved.
X
Y
U
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39. CoAP
CoAP
CoAP
CoAP
UDP
UDP
UDP
UDP
IPv6
IPv6
IPv6
IPv6
6LoWPAN-HC
6LoWPAN-HC
6LoWPAN-HC
6LoWPAN-HC
6top
6top
6top
6top
15.4e TSCH
15.4e TSCH
15.4e TSCH
15.4e TSCH
15.4 PHY
15.4 PHY
15.4 PHY
15.4 PHY
15.4 PHY
15.4 PHY
TSCH
TSCH
Multi-protocol
Multi-protocol
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40. CoAP
CoAP
CoAP
CoAP
UDP
UDP
UDP
UDP
IPv6
1st IPv6
1stIPv6
IPv6
6LoWPAN-HC
6LoWPAN-HC
Next
6LoWPAN-HC
Next
6LoWPAN-HC
6top
6top
6top
6top
15.4e TSCH
15.4e TSCH
15.4e TSCH
15.4e TSCH
15.4 PHY
15.4 PHY
15.4 PHY
15.4 PHY
A
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X
Y
U
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41. Backbone
Router
intra/
Internet
6TiSCH
LLN
Backbone
Attached
LLN*
6TiSCH
LLN
PCE
Virtual
devices
NMS
* LLN ==
Low Power Lossy Network
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42. 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
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43. © 2013-2014 Cisco and/or its affiliates. All rights reserved.
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44. Connected
Route to
subnet
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45. Default
Route
In RIB
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Gateway to the outside
participates to some
IGP with external
network and attracts all
extra-subnet traffic via
protocols over the
backbone
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46. Directly upon NS(ARO)
or indirectly upon DAR
message, the backbone
router performs DAD on
behalf of the wireless
device.
NS DAD
(ARO)
DAD
NS
(ARO)
NS
(ARO)
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47. The BR maintains a
route to the WSN
node for the DAO
Lifetime over instance
VRF. VFR may be
mapped onto a VLAN
on the backbone.
Optional
NA(O)
NA
(ARO)
DAC
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48. The BR maintains a
route to the WSN
node for the DAO
Lifetime over instance
VRF. VFR may be
mapped onto a VLAN
on the backbone.
Optional
NA(O)
RPL
DAO
Host
Route
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49. DAD option has:
Unique ID
TID (SeqNum)
Defend with NA if:
Different OUID
Newer TID
NS DAD
(ARO)
NA (ARO)
NS
(ARO)
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50. DAD option has:
Unique ID
TID (SeqNum)
Defend with NA if:
Different OUID
Newer TID
Optional
NA(ARO)
NA (ARO) with
older TID (loses)
RPL
DAO
Host
Route
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51. NA ARO option has:
Unique ID
TID (SeqNum)
NS
lookup
NA (ARO)
Packet
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52. Resolution (2)
NS
lookup
Mixed mode ND
BBR proxying over
the backbone
NA (ARO)
Packet
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53. • Used to resolve conflicts
• Need In ND: TID to detect movement ->eARO
• Need In RPL: Object Unique ID if we use RPL for DAD
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 = 2 |
Status
|
Reserved
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Reserved |T|
TID
|
Registration Lifetime
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+
OUID
( EUI-64 or equivalent )
+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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Figure 2: EARO
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54. 6TiSCH at a glance
Deterministic IPv6 over IEEE802.15.4e TimeSlotted Channel
Hopping (6TiSCH)
The Working Group will focus on enabling IPv6 over the TSCH
mode of the IEEE802.15.4e standard. The scope of the WG
includes one or more LLNs, each one connected to a backbone
through one or more LLN Border Routers (LBRs).
Active drafts
http://tools.ietf.org/html/draft-ietf-6tisch-terminology
http://tools.ietf.org/html/draft-ietf-6tisch-tsch
http://tools.ietf.org/html/draft-ietf-6tisch-architecture
http://tools.ietf.org/html/draft-ietf-6tisch-minimal
http://tools.ietf.org/html/draft-wang-6tisch-6top
http://tools.ietf.org/html/draft-ohba-6tisch-security
http://tools.ietf.org/html/draft-sudhaakar-6tisch-coap
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55. Routing IP
in
LLNs
BRKEWN-3012
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Unclassified
55

56. • Hidden terminal
• Interference domains grows faster that range
• Density => low power => multihop => routing
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57. Aka
stateful
vs.
On-demand routing
Note: on-demand breaks
control vs. Data plane
separation
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58. • Aka SPF vs. Bellman-Ford
• LS requires full state and convergence
• LS can be very quiet on stable topologies
• DV hides topolical complexities and changes
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59. 0
Optimized Routing Approach
(ORA) spans advertisements
for any change
Routing overhead can be
reduced if stretch is allowed:
Least Overhead Routing
Approach (LORA)
For instance Fisheye and
zone routing provide a
precise routing when closeby
and sense of direction when
afar
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60. A Directed Acyclic Graph (DAG) is
formed by a collection of vertices (nodes)
and edges (links).
0
1
Clusterhead
2
1
1
2
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).
0
2
3
2
3
2
3
2
4
3
3
A Destination Oriented DAG (DODAG) is
a DAG that comprises a single root node.
Here a DAG that is partitioned in 2
DODAG
3
4
3
5
5
6
44 5
4
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61. 0
• In Green: A‟s subDAG.
1
1
• Impacted if A‟s connectivity is
broken
• Domain for routing recovery
(or reverse subDAG)
Potential SPAN on B‟s DAO
Thus potential return paths
Fanout must be controlled to
limit intermediate states
1
2
0
2
3
A
2
3
2
3
• In Red: B‟s fanout DAG
•
•
•
•
Clusterhead
2
2
4
3
3
3
4
3
5
5
6
44 5
4
B
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61

62. Routing over radios
63

63. 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
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64

64. Potentially Large Peer Set
Highly Variable Capabilities
Metrics (e.g. RSSI, ETX…)
L3 Reachability (::/0, …)
Constraints (Power …)
Selection Per Objective
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65

65. • 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)
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66

66. 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
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67

67. Stretch vs. Control
Optimize table sizes and updates
Optimized Routing Approach (ORA) vs
Least Overhead Routing Approach (LORA)
Non Equal Cost multipath
Directed Acyclic Graphs (DAG) a MUST
Maybe also, Sibling routing
on-demand routes (reactive)
Forwarding and retries
Same vs. Different next hop
Validation of the Routing plane
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Objective Routing
Weighted Hop Count the wrong metric
Instances per constraints and metrics
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68

68. 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
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69

69. RPL Concepts
70

70. RPL is an extensible proactive IPv6 DV protocol
Supports MP2P, P2MP and P2P
P2P reactive extension
RPL specifically designed for LLNs
Agnostic to underlying link layer technologies
(802.15.4, PLC, Low Power WiFi)
Minimum topological awareness
Data Path validation
Non-Equal Cost Multipath Fwd
Instantiation per constraints/metrics
Autonomic Subnet G/W Protocol
Optimized Diffusion over NBMA
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71

71. Controlling the control … by design
Distance Vector as opposed to 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 as opposed to Reactive
• Actually both with so-called P2P experimental specification
Datapath validation
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72

72. 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
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73

73. 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).
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74

74. 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 |Version Number |
Rank
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|G|0| MOP | Prf |
DTSN
|
Flags
|
Reserved
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+
+
|
|
+
DODAGID
+
|
|
+
+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Option(s)...
+-+-+-+-+-+-+-+-+
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76

75. •
: : 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
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77

76. Extend the generic behavior
• For a specific need / use case
Used in parent selection
• Contraints
• Policies
• Metrics
Position in the DAG
Computes the Rank increment
• Based on hop metrics
• Do NOT use OF0 for adhoc radios!
• (OF 0 uses traditional weighted hop count)
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78

77. 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 |Version Number |
Rank
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|G|0| MOP | Prf |
DTSN
|
Flags
|
Reserved
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+
+
|
|
+
DODAGID
+
|
|
+
+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Option(s)...
+-+-+-+-+-+-+-+-+
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79

78. +-----+-----------------------------------------------------+
| MOP | Description
|
+-----+-----------------------------------------------------+
|
0
| No Downward routes maintained by RPL
|
|
1
| Non-Storing Mode of Operation
|
|
2
| Storing Mode of Operation with no multicast support |
|
3
| Storing Mode of Operation with multicast support
|
|
|
|
|
| All other values are unassigned
|
+-----+-----------------------------------------------------+
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80

79. 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 |K|D|
Flags
|
Reserved
| DAOSequence
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
|
+
+
|
|
+
DODAGID*
+
|
|
+
+
|
|
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|
Option(s)...
+-+-+-+-+-+-+-+-+
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81

80. Parent is default GW, advertizes owned PIO (L bit on)
RPL Router autoconfigures Addr from parent PIO
RPL Router advertises Prefix via self to parent
RPL Router also advertises children Prefix
A::A
A
C:
A::B
::/0 via B::B
::/0 via A::A
C:: connected
B
B:
B:: connected
B::B
A::
B::D
B::C
B:: connected
D:
C
D
connected
::/0 via B::B
C::
via
B::C
D::
via
B::D
A:
A::
connected
B::
via
A::B
C::
via
A::B
D::
via
A::B
B:: connected
D:: connected
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82

81. For Your
Reference
Parent is default GW, propagates root PIO (L-bit off)
Parent Address in the PIO (with R bit)
RPL Router autoconfigures Address from parent PIO
RPL Router advertises Address via self to parent
RPL Router also advertises children Addresses
A::A
A
C:
::/0 via A::B
A::B
A::B
A::C
B
A::
A::D
A::C
C
D
connected
self
~onlink
::/0 via A::A
A::A connected
A::B
::/0 via A::B
connected
A::D
connected
A::D
connected
A::
~onlink
A:
A::A self
A::B
connected
A::C
via
A::B
A::D
via
A::B
A::
~onlink
self
A::
self
A::C
D:
A::B
© 2013-2014 Cisco and/or its affiliates. All rights reserved.
B:
~onlink
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83

82. Parent is default GW, propagates root PIO (L-bit off)
Parent Address in the PIO (with R bit)
RPL Router autoconfigures Address from parent PIO
RPL Router advertises Address via Parent to Root
Root recursively builds a Routing Header back
A::A
A
C:
::/0 via A::B
A::B
Target A::C via
Transit A::B
A::B
A::C
A::D
A::C
self
~onlink
::/0 via A::A
A::A self
A::B
A::D
via
A::B
~onlink
A::B
connected
self
~onlink
via
~onlink
A::
© 2013-2014 Cisco and/or its affiliates. All rights reserved.
A::
A::C
self
connected
connected
A::
::/0 via A::B
A::B
A::B
A::A connected
A::D
D
D:
A::B
C
A: (root)
B:
A::
B
connected
A::D
via
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84

83. For Your
Reference
Parent is default GW, advertizes owned PIO (L bit on)
RPL Router autoconfigures Address from parent PIO
RPL Router advertises Prefix via Address to Root
Root recursively builds a Routing Header back
A::A
A
C:
A::B
B:: connected
B::B
C:: connected
B
A::
D:
C
D
A: (root)
B:
A::
::/0 via A::A
B::D
B::C
Target C::/ via
Transit B::C
::/0 via B::B
connected
B::
via
A::B
C::
via
B::C
D::
via
B::D
connected
B:: connected
::/0 via B::B
B:: connected
D:: connected
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D::3
via
B::D
via
A::B
connected
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85

84. Hidden node/terminal/station
A
B
C
D
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Flooding interferes with itself
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86

85. Suppression of redundant copies
Do not send copy if K copies received
Jitter for Collision Avoidance
First half is mute, second half is jittered
Exponential backoff
Double I after period I, Reset I on inconsistency
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87

86. For Your
Reference
Node Metrics
Link Metrics
Node State and Attributes Object
Purpose is to reflects node workload (CPU,
Memory…)
“O” flag signals overload of resource
“A” flag signal node can act as traffic
aggregator
Throughput Object
Currently available throughput (Bytes per
second)
Throughput range supported
Node Energy Object
“T” flag: Node type: 0 = Mains, 1 = Battery, 2 =
Scavenger
“I” bit: Use node type as a constraint
(include/exclude)
“E” flag: Estimated energy remaining
Latency
Can be used as a metric or constraint
Constraint - max latency allowable on path
Metric - additive metric updated along path
Hop Count Object
Can be used as a metric or constraint
Constraint - max number of hops that can be
traversed
Metric - total number of hops traversed
Link Reliability
Link Quality Level Reliability (LQL)
0=Unknown, 1=High, 2=Medium, 3=Low
Expected Transmission Count (ETX)
(Average number of TX to deliver a
packet)
Link Colour
Metric or constraint, arbitrary admin value
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88

87. Applying RPL
89

88. At a given point of time
connectivity is
(fuzzy)
Radio link
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91

89. 1st
•
•
•
•
pass (DIO)
Establishes a logical DAG topology
Trickle Subnet/config Info
Sets default route
Self forming / self healing
0
1
Clusterhead
2
1
1
2
2
3
2
3
2
3
4
2
2nd pass (DAO)
•
•
•
•
•
paints with addresses and prefixes
Any to any reachability
But forwarding over DAG only
saturates upper links of the DAG
And does not use the full mesh
properly
4
4
3
5
6
3
4
5
5
Potential link
Link selected as parent link
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92

90. 0
1
Clusterhead
2
A‟s link to root fails
1
1
2
A loses connectivity
Either poisons or detaches a subdag
A
2
3
2
3
2
3
4
In black:
2
4
4
the potentially impacted zone
That is A‟s subDAG
3
5
6
3
4
5
5
Potential link
Link selected as parent link
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93

91. 0
1
Clusterhead
2
1
B can reparent a same Rank so
B‟s subDAG is safe
0
2
A
2
3
2
B
3
1
The rest of A‟s subDAG is isolated
3
1
4
4
4
Either poison ar build a floating
DAG as illustrated
In the floating DAG A is root
The structure is preserved
2
5
6
2
4
5
5
Potential link
Link selected as parent link
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94

92. 0
1
Clusterhead
2
1
Once poisined nodes are
identified
2
2
It is possible for A to reparent safely
A
2
3
2
3
A‟s descendants inherit from Rank
shift
3
3
4
3
4
Note: a depth dependent timer can
help order things
4
4
5
6
4
4
5
5
Potential link
Link selected as parent link
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95

93. 0
1
Clusterhead
3
1
A new DAG iteration
• In Grey, the new DAG
progressing
2
3
2
3
Metrics have changed, the DAG
may be different
Forwarding upwards traffic
from old to new iteration is
allowed but not the other way
around
1
2
2
3
4
2
4
4
3
5
6
3
4
5
5
Potential link
Link selected as parent link
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96

94. 0
A second root is available
1
• (within the same instance)
1
0
2
3
2
1 root = 1 DODAG
3
2
3
1 Node belongs to 1 DODAG
2
4
• (at most, per instance)
3
3
Nodes may JUMP
3
4
• from one DODAG to the next
• up the DODAG
1
2
The DAG is partitioned
Nodes may MOVE
Clusterhead
2
3
5
5
6
44 5
4
Going Down MAY cause loops
• May be done under CTI control
Potential link
Link selected and oriented by DIO
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97

95. 0
Running as Ships-in-the-night
1
Clusterhead
2
1
1 instance = 1 DAG
1
2
A DAG implements constraints
2
3
2
3
Serving different Objective
Functions
2
3
4
2
3
For different optimizations
Forwarding along a DODAG (like
A
a vlan)
3
3
4
5
4
3
4
Potential link
Constrained instance
Default instance
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98

96. 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
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99

97. RFC 6206: The Trickle Algorithm
RFC 6550: RPL: IPv6 Routing Protocol for LLNs
RFC 6551: Routing Metrics Used for Path Calculation in LLNs
RFC 6552: Objective Function Zero for the Routing Protocol for LLNs
RFC 6553: RPL Option for Carrying RPL Information in Data-Plane Datagrams
RFC 6554: An IPv6 Routing Header for Source Routes with RPL
RFC 6719: MRHOF Objective Function with hysteresis
draft-ietf-roll-trickle-mcast: Multicast Protocol for LLNs
draft-vilajosana-6tisch-minimal: Minimal 6TiSCH Configuration
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100

98. The Internet is going through its most considerable change
since the first days, adding a nervous system to the bug
brain. Potential is immense and unpredictable.
Made possible by IPv6
But not at the core and unbeknownst to the core
Stimulated by radio access
Enabling new devices and usages
The change happens in the Fringe, which is in fact a
collection of virtualized fringes. The polymorphic Internet is
already there.
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101

99. “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.”
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102