gogo6 IPv6 Video Series. Event, presentation and speaker details below: EVENT gogoNET LIVE! 4: IPv6 & The Internet of Things. http://gogonetlive.com November 12 – 14, 201, Silicon Valley, California Agenda: http://gogonetlive.com/gogonetlive4-agenda.asp PRESENTATION IETF 6TiSCH, a New Standardization Effort to Combine IPv6 Connectivity Abstract: http://www.gogo6.com/profiles/blogs/my-presentation-at-gogonet-live-4 Presentation video: http://www.gogo6.com/video/ietf-6tisch-a-new-standardization-effort-to-combine-ipv6-connecti Interview video: http://www.gogo6.com/video/6-xavi-interview-iot SPEAKER Xavier Vilajosana - Teacher/Researcher, UC Berkeley Bio/Profile: http://www.gogo6.com/profile/XavierVilajosana MORE Learn more about IPv6 on the gogoNET social network and our online training courses http://www.gogo6.com/main Get free IPv6 connectivity with Freenet6 http://www.gogo6.com/Freenet6 Subscribe to the gogo6 IPv6 Channel on YouTube http://www.youtube.com/subscription_center?add_user=gogo6videos Follow gogo6 on Twitter http://twitter.com/gogo6inc Like gogo6 on Facebook http://www.facebook.com/pages/IPv6-products-community-and-services-gogo6/161626696777

1. IETF 6TiSCH, a New Standardization
Effort to Combine IPv6 Connectivity
with Industrial Performance
Xavier Vilajosana
UC Berkeley
Universitat Oberta de Catalunya

2. The Internet of Things Stack
web-like interaction
CoAP
UDP
Internet Integration
6LoWPAN
scheduling
“gap”
Low-power reliability
IEEE802.15.4e
simple hardware
IEEE802.15.4

3. Outline
1. Wireless Challenges
2. IEEE802.15.4e
3. 6TiSCH

4. Wireless Challenges

5. First Challenge: External Interference
IEEE802.11
(Wi-Fi)
IEEE802.15.1
(Bluetooth)
IEEE802.15.4

6. Second Challenge: Multipath Fading

7. Second Challenge: Multipath Fading
• Separate sender and
receiver by 100cm
• Have sender send bursts of
1000 packets
• Have receiver count the
number of received packets
• Move transmitter around in
a 20cmx35cm area and start
over

8. Second Challenge: Multipath Fading
ch.11

9. Second Challenge: Multipath Fading
ch.11
ch.12
ch.19
ch.20
ch.13
ch.14
ch.21
ch.22
ch.15
ch.16
ch.23
ch.24
ch.17
ch.18
ch.25
ch.26

10. IEEE802.15.4e

11. The Internet of Things Stack
web-like interaction
CoAP
UDP
Internet Integration
6LoWPAN
scheduling
“gap”
Low-power reliability
IEEE802.15.4e
simple hardware
IEEE802.15.4

12. Status
• Published 16 April 2012
• Only amends MAC layer of
IEEE802.15.4-2011:
– Does not modify PHY layer
• “Timeslotted Channel
Hopping” (TSCH) mode:
–
Ultra low-power operation by
synchronizing nodes
– Ultra high reliability through
channel hopping

13. Communication Schedule
A
• A super-frame repeats over time
– Number of slots in a superframe is tunable
– Each cell can be assigned to a pair of motes, in a
given direction
B
C
16 channel offsets
E
D
F
G
I
H
J
e.g. 31 time slots (310ms)

14. A Slot
9.976ms
2.120ms
2.000ms
≤ 4.256ms
0.800ms
0.400ms
2.400ms

15. 2268
2273
2278
2283
2288
2293
channelOffset=11
slotOffset=14
=14
16 channel offsets
2263
ASN*=2277
Channel Hopping
e.g. 31 time slots (310ms)
frequencyChannel=(channelOffset+ASN)%16+11
Now:
Ch. 11 (2.405GHz)
Next slotframe:
Ch. 26 (2.480GHz)
*Absolute Slot Number

16. Slotted Structure: Trade-Off
•
•
A
Cells are assigned according to application
requirements
Tunable trade-off between
– packets/second
– latency
– robustness
B
C
…and energy consumption
16 channel offsets
E
D
F
G
I
H
J
e.g. 31 time slots (310ms)

17. Timeslotted Channel Hopping
B
D
A
DATA
ACK
C->A
A->C
C
10s to 1000s
D->C
D->B
B->A
slotOffset
Typically 16
channelOffset
C->A
• Trade-off bandwidth,
redundancy, latency for power
consumption.
• 50% PDR: schedule more links
• Average power consumption:
function of number of scheduled
cells.
• How Mechanisms to monitor
and maintain schedule is out of
scope.

18. IEEE802.15.4e: Heritage
• 2006: Dust Networks’s Time Sync. Mesh Protocol (TSMP)
– Break-through technology [1]
•
•
•
•
26 days
3.6 million packets generated
only 17 packets lost
99.9995% end-to-end reliability
– Applicable to industrial application
• 2008: WirelessHART
– Wireless extension of HART, the de-facto standard for
industrial monitoring
• 2012: IEEE 802.15.4e
– Amends MAC protocol of IEEE 802.15.4-2011
• Proven Technology. Commercial solutions are
available.
[1] Channel-Specific Wireless Sensor Network Path Data,
Doherty, Linday, Simon, ICCCN 2007

19. 6TiSCH

20. The Internet of Things Stack
web-like interaction
CoAP
UDP
Internet Integration
6LoWPAN
scheduling
“gap”
Low-power reliability
IEEE802.15.4e
simple hardware
IEEE802.15.4

21. 6TiSCH: Status
• Discussions started in December 2012
• Very traditional IETF procedure
– IETF mailing list created 01/24/2013
– 160+ members (mix between academic and nonacademics)
– First face-to-face meetings at IETF 86 in Orlando
(March 2013)
– BOF at IETF 87 in Berlin
– IETF 88 draft adoption in Vancouver

22. 6TiSCH: In Practice
• Mailing list
– 6tisch@ietf.org
– https://www.ietf.org/mailman/listinfo/6tisch
• Weekly Webex calls
• Homepage
– https://bitbucket.org/6tisch/
• Internet drafts:
– An Architecture for IPv6 over Time Synchronized Channel Hopping
– Terminology in IPv6 over Time Slotted Channel Hopping
– Using IEEE802.15.4e TSCH in an LLN context: Overview, Problem Statement and
Goals
– 6TiSCH Operation Sublayer (6top)
– Minimal 6TiSCH Configuration
– 6TiSCH Data Model for CoAP
– Security Framework and Key Management Protocol Requirements for 6TiSCH
– A standard compliant security framework for Low-power and Lossy Networks

23. Charter
• Define an architecture to describe the design of
6TiSCH networks.
• Define an Information Model containing the
management requirements of a 6TiSCH node.
• Define a Minimal mode of operation outlining
how to build a 6TiSCH network using the Routing
Protocol for LLNs (RPL) and a static TSCH
schedule.
SCOPE: Charter limit the scope to distributed routing over a static schedule

24. Architecture

25. 6top Operational Layer
• Logical positioning of layers
Higher Layers
Information and Data Model for
interacting with 6top
6top
802.15.4e TSCH

26. Commands

27. Using 6top with a PCE
• PCE has full knowledge of
topology and traffic
requirements
• PCE computes schedule
• Communicates with nodes
to configure their schedule
• PCE-node protocol
– e.g. CoAP
• PCE typically schedules hard
cells
• Charter Scope: define
operational API an 6top
mechanisms
PCE
backbone
BBR
LLN
CoAP
6top
TSCH
node

28. 6top with distributed scheduling
• Distributed scheduling can
use RPL routes
• Neighbor schedule
bandwidth with each other,
rather than explicit cells
– Soft cells
• 6top monitoring process
monitors performance of
cells and reschedules the
ones that perform bad.
• Charter Scope: define
operational API an 6top
mechanisms
A
B
C
D
E

29. 6TiSCH Resources
• Management Resources using CoAP
6top management resources and the related URI paths
Name
Accessibility 6top Commands
URI path
Neighbor Table
CREATE/READ/DELETE/UPDATE
6t/Neighbor
Slotframe Table
CREATE/READ/DELETE/UPDATE
6t/slotframe
Cell Table
CREATE/READ/DELETE/UPDATE
6t/Cell
Time Source
CREATE/READ/DELETE/UPDATE
6t/TimeSource
Bundle Table
CREATE/READ/DELETE/UPDATE
6t/Bundle
Track Table
CREATE/READ/DELETE/UPDATE
6t/Track
EB Table
CREATE/READ/DELETE/UPDATE
6t/EB

30. Minimal Static Schedule

31. RPL on Minimal
• RFC6552 “Objective Function Zero for the
Routing Protocol for Low-Power and Lossy
Networks (RPL)”
• Definitions
– Rf: rank_factor
– Sp: step_of_rank
– Sr: stretch_of_rank
P
R(P)
N
R(N)=R(N)+rank_increase
rank_increase = (Rf*Sp + Sr) * MinHopRankIncrease

32. Thank you!
xvilajosana@eecs.berkeley.edu
32

33. Example
• Given:
–
–
–
–
–
–
–
Rf = 1
Sp = 2* ETX
Sr = 0
minHopRankIncrease = 256 (default in RPL)
ETX=(xmit/ack)
r(n) = r(p) + rank_increase
rank_increase= (Rf*Sp + Sr) *
minHopRankIncrease
– rank_increase=(512*xmit/ack)
0
R(0)=0
DAGRank(R(0)) = 0
1
R(1)=R(0)+683=683
DAGRank(R(1)) = 2
2
R(2)=R(1)+683=1366
DAGRank(R(1)) = 5
3
R(3)=R(2)+683=2049
DAGRank(R(1)) = 8
4
R(4)=R(3)+683=2732
DAGRank(R(1)) = 10
5
R(5)=R(4)+683=3415
DAGRank(R(1)) = 13
• Example:
– 5-hop network
– r(0)=0
– xmit=100 ack=75 for all links