draft-ietf-6tisch-tsch-03.txt   draft-ietf-6tisch-tsch-04.txt 
6TiSCH T. Watteyne, Ed. 6TiSCH T. Watteyne, Ed.
Internet-Draft Linear Technology Internet-Draft Linear Technology
Intended status: Informational MR. Palattella Intended status: Informational MR. Palattella
Expires: April 30, 2015 University of Luxembourg Expires: June 22, 2015 University of Luxembourg
LA. Grieco LA. Grieco
Politecnico di Bari Politecnico di Bari
October 27, 2014 December 19, 2014
Using IEEE802.15.4e TSCH in an IoT context: Using IEEE802.15.4e TSCH in an IoT context:
Overview, Problem Statement and Goals Overview, Problem Statement and Goals
draft-ietf-6tisch-tsch-03 draft-ietf-6tisch-tsch-04
Abstract Abstract
This document describes the environment, problem statement, and goals This document describes the environment, problem statement, and goals
for using the IEEE802.15.4e TSCH MAC protocol in the context of LLNs. for using the IEEE802.15.4e TSCH MAC protocol in the context of LLNs.
The set of goals enumerated in this document form an initial set The set of goals enumerated in this document form an initial set
only. only.
Status of This Memo Status of This Memo
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
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time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 30, 2015. This Internet-Draft will expire on June 22, 2015.
Copyright Notice Copyright Notice
Copyright (c) 2014 IETF Trust and the persons identified as the Copyright (c) 2014 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
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4.7. Deterministic Behavior . . . . . . . . . . . . . . . . . 8 4.7. Deterministic Behavior . . . . . . . . . . . . . . . . . 8
4.8. Scheduling Mechanisms . . . . . . . . . . . . . . . . . . 9 4.8. Scheduling Mechanisms . . . . . . . . . . . . . . . . . . 9
4.9. Secure Communication . . . . . . . . . . . . . . . . . . 9 4.9. Secure Communication . . . . . . . . . . . . . . . . . . 9
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10 7. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 10
8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 10
8.1. Normative References . . . . . . . . . . . . . . . . . . 10 8.1. Normative References . . . . . . . . . . . . . . . . . . 10
8.2. Informative References . . . . . . . . . . . . . . . . . 10 8.2. Informative References . . . . . . . . . . . . . . . . . 10
8.3. External Informative References . . . . . . . . . . . . . 13 8.3. External Informative References . . . . . . . . . . . . . 13
Appendix A. TSCH Protocol Highlights . . . . . . . . . . . . . . 16 Appendix A. TSCH Protocol Highlights . . . . . . . . . . . . . . 15
A.1. Timeslots . . . . . . . . . . . . . . . . . . . . . . . . 16 A.1. Timeslots . . . . . . . . . . . . . . . . . . . . . . . . 15
A.2. Slotframes . . . . . . . . . . . . . . . . . . . . . . . 16 A.2. Slotframes . . . . . . . . . . . . . . . . . . . . . . . 16
A.3. Node TSCH Schedule . . . . . . . . . . . . . . . . . . . 16 A.3. Node TSCH Schedule . . . . . . . . . . . . . . . . . . . 16
A.4. Cells and Bundles . . . . . . . . . . . . . . . . . . . . 17 A.4. Cells and Bundles . . . . . . . . . . . . . . . . . . . . 16
A.5. Dedicated vs. Shared Cells . . . . . . . . . . . . . . . 17 A.5. Dedicated vs. Shared Cells . . . . . . . . . . . . . . . 17
A.6. Absolute Slot Number . . . . . . . . . . . . . . . . . . 18 A.6. Absolute Slot Number . . . . . . . . . . . . . . . . . . 17
A.7. Channel Hopping . . . . . . . . . . . . . . . . . . . . . 18 A.7. Channel Hopping . . . . . . . . . . . . . . . . . . . . . 18
A.8. Time Synchronization . . . . . . . . . . . . . . . . . . 19 A.8. Time Synchronization . . . . . . . . . . . . . . . . . . 18
A.9. Power Consumption . . . . . . . . . . . . . . . . . . . . 19 A.9. Power Consumption . . . . . . . . . . . . . . . . . . . . 19
A.10. Network TSCH Schedule . . . . . . . . . . . . . . . . . . 20 A.10. Network TSCH Schedule . . . . . . . . . . . . . . . . . . 19
A.11. Join Process . . . . . . . . . . . . . . . . . . . . . . 20 A.11. Join Process . . . . . . . . . . . . . . . . . . . . . . 20
A.12. Information Elements . . . . . . . . . . . . . . . . . . 21 A.12. Information Elements . . . . . . . . . . . . . . . . . . 20
A.13. Extensibility . . . . . . . . . . . . . . . . . . . . . . 21 A.13. Extensibility . . . . . . . . . . . . . . . . . . . . . . 20
Appendix B. TSCH Gotchas . . . . . . . . . . . . . . . . . . . . 21 Appendix B. TSCH Gotchas . . . . . . . . . . . . . . . . . . . . 21
B.1. Collision Free Communication . . . . . . . . . . . . . . 21 B.1. Collision Free Communication . . . . . . . . . . . . . . 21
B.2. Multi-Channel vs. Channel Hopping . . . . . . . . . . . . 21 B.2. Multi-Channel vs. Channel Hopping . . . . . . . . . . . . 21
B.3. Cost of (continuous) Synchronization . . . . . . . . . . 22 B.3. Cost of (continuous) Synchronization . . . . . . . . . . 21
B.4. Topology Stability . . . . . . . . . . . . . . . . . . . 22 B.4. Topology Stability . . . . . . . . . . . . . . . . . . . 22
B.5. Multiple Concurrent Slotframes . . . . . . . . . . . . . 22 B.5. Multiple Concurrent Slotframes . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 23 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 22
1. Introduction 1. Introduction
IEEE802.15.4e [IEEE802154e] was published in 2012 as an amendment to IEEE802.15.4e [IEEE802154e] was published in 2012 as an amendment to
the Medium Access Control (MAC) protocol defined by the the Medium Access Control (MAC) protocol defined by the
IEEE802.15.4-2011 [IEEE802154] standard. IEEE802.15.4e will be IEEE802.15.4-2011 [IEEE802154] standard. IEEE802.15.4e will be
rolled into the next revision of IEEE802.15.4, scheduled to be rolled into the next revision of IEEE802.15.4, scheduled to be
published in 2015. The Timeslotted Channel Hopping (TSCH) mode of published in 2015. The Timeslotted Channel Hopping (TSCH) mode of
IEEE802.15.4e is the object of this document. IEEE802.15.4e is the object of this document.
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announces in its Enhanced Beacon. announces in its Enhanced Beacon.
3. Schedule transmissions of Enhanced Beacons to advertise the 3. Schedule transmissions of Enhanced Beacons to advertise the
presence of the network. presence of the network.
4.3. Multi-Hop Topology 4.3. Multi-Hop Topology
RPL, given a weighted connectivity graph, determines multi-hop RPL, given a weighted connectivity graph, determines multi-hop
routes. The LLC needs to: routes. The LLC needs to:
1. Define a mechanism to gather topological information, which it 1. Define a mechanism to gather topological information, node and
can then feed to RPL. link state, which it can then feed to RPL.
2. Ensure that the TSCH schedule contains cells along the multi-hop 2. Ensure that the TSCH schedule contains cells along the multi-hop
routes identified by RPL. routes identified by RPL.
3. Where applicable, maintain independent sets of cells to transport 3. Where applicable, maintain independent sets of cells to transport
independent flows of data. independent flows of data.
4.4. Routing and Timing Parents 4.4. Routing and Timing Parents
At all times, a TSCH node needs to have a time source neighbor it can At all times, a TSCH node needs to have a time source neighbor it can
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This memo is an informational overview of existing standards, and This memo is an informational overview of existing standards, and
does define any new mechanisms or protocols. does define any new mechanisms or protocols.
It does describe the need for the 6TiSCH WG to define a secure It does describe the need for the 6TiSCH WG to define a secure
solution. In particular, Section 4.1 describes security in the join solution. In particular, Section 4.1 describes security in the join
process. Section 4.9 discusses data frame protection. process. Section 4.9 discusses data frame protection.
7. Acknowledgments 7. Acknowledgments
Special thanks to Jonathan Simon for his review and valuable Special thanks to Jonathan Simon for his review and valuable
comments. Thanks to the IoT6 European Project (STREP) of the 7th comments. Thanks to Guillaume Gaillard and Dominique Barthel for
Framework Program (Grant 288445). their in-depth review. Thanks to the IoT6 European Project (STREP)
of the 7th Framework Program (Grant 288445).
8. References 8. References
8.1. Normative References 8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References 8.2. Informative References
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Address Autoconfiguration", RFC 4862, September 2007. Address Autoconfiguration", RFC 4862, September 2007.
[RFC3819] Karn, P., Bormann, C., Fairhurst, G., Grossman, D., [RFC3819] Karn, P., Bormann, C., Fairhurst, G., Grossman, D.,
Ludwig, R., Mahdavi, J., Montenegro, G., Touch, J., and L. Ludwig, R., Mahdavi, J., Montenegro, G., Touch, J., and L.
Wood, "Advice for Internet Subnetwork Designers", BCP 89, Wood, "Advice for Internet Subnetwork Designers", BCP 89,
RFC 3819, July 2004. RFC 3819, July 2004.
[RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6 [RFC2460] Deering, S. and R. Hinden, "Internet Protocol, Version 6
(IPv6) Specification", RFC 2460, December 1998. (IPv6) Specification", RFC 2460, December 1998.
[I-D.ietf-6tisch-tsch] [I-D.ietf-6tisch-6top-interface]
Watteyne, T., Palattella, M., and L. Grieco, "Using Wang, Q., Vilajosana, X., and T. Watteyne, "6TiSCH
IEEE802.15.4e TSCH in an IoT context: Overview, Problem Operation Sublayer (6top) Interface", draft-ietf-6tisch-
Statement and Goals", draft-ietf-6tisch-tsch-02 (work in 6top-interface-02 (work in progress), October 2014.
progress), October 2014.
[I-D.ietf-6tisch-architecture] [I-D.ietf-6tisch-architecture]
Thubert, P., Watteyne, T., and R. Assimiti, "An Thubert, P., Watteyne, T., and R. Assimiti, "An
Architecture for IPv6 over the TSCH mode of IEEE Architecture for IPv6 over the TSCH mode of IEEE
802.15.4e", draft-ietf-6tisch-architecture-03 (work in 802.15.4e", draft-ietf-6tisch-architecture-04 (work in
progress), July 2014. progress), October 2014.
[I-D.ietf-6tisch-coap]
Sudhaakar, R. and P. Zand, "6TiSCH Resource Management and
Interaction using CoAP", draft-ietf-6tisch-coap-02 (work
in progress), December 2014.
[I-D.ietf-6tisch-minimal]
Vilajosana, X. and K. Pister, "Minimal 6TiSCH
Configuration", draft-ietf-6tisch-minimal-04 (work in
progress), November 2014.
[I-D.ietf-6tisch-terminology] [I-D.ietf-6tisch-terminology]
Palattella, M., Thubert, P., Watteyne, T., and Q. Wang, Palattella, M., Thubert, P., Watteyne, T., and Q. Wang,
"Terminology in IPv6 over the TSCH mode of IEEE "Terminology in IPv6 over the TSCH mode of IEEE
802.15.4e", draft-ietf-6tisch-terminology-02 (work in 802.15.4e", draft-ietf-6tisch-terminology-02 (work in
progress), July 2014. progress), July 2014.
[I-D.ietf-6tisch-minimal]
Vilajosana, X. and K. Pister, "Minimal 6TiSCH
Configuration", draft-ietf-6tisch-minimal-03 (work in
progress), October 2014.
[I-D.ietf-6tisch-6top-interface]
Wang, Q., Vilajosana, X., and T. Watteyne, "6TiSCH
Operation Sublayer (6top) Interface", draft-ietf-6tisch-
6top-interface-01 (work in progress), July 2014.
[I-D.wang-6tisch-6top-sublayer] [I-D.wang-6tisch-6top-sublayer]
Wang, Q., Vilajosana, X., and T. Watteyne, "6TiSCH Wang, Q., Vilajosana, X., and T. Watteyne, "6TiSCH
Operation Sublayer (6top)", draft-wang-6tisch-6top- Operation Sublayer (6top)", draft-wang-6tisch-6top-
sublayer-01 (work in progress), July 2014. sublayer-01 (work in progress), July 2014.
[I-D.ietf-6tisch-coap]
Sudhaakar, R. and P. Zand, "6TiSCH Resource Management and
Interaction using CoAP", draft-ietf-6tisch-coap-01 (work
in progress), July 2014.
[I-D.thubert-roll-forwarding-frags] [I-D.thubert-roll-forwarding-frags]
Thubert, P. and J. Hui, "LLN Fragment Forwarding and Thubert, P. and J. Hui, "LLN Fragment Forwarding and
Recovery", draft-thubert-roll-forwarding-frags-02 (work in Recovery", draft-thubert-roll-forwarding-frags-02 (work in
progress), September 2013. progress), September 2013.
[I-D.tsao-roll-security-framework] [I-D.tsao-roll-security-framework]
Tsao, T., Alexander, R., Daza, V., and A. Lozano, "A Tsao, T., Alexander, R., Daza, V., and A. Lozano, "A
Security Framework for Routing over Low Power and Lossy Security Framework for Routing over Low Power and Lossy
Networks", draft-tsao-roll-security-framework-02 (work in Networks", draft-tsao-roll-security-framework-02 (work in
progress), March 2010. progress), March 2010.
skipping to change at page 13, line 14 skipping to change at page 12, line 51
[I-D.ietf-roll-p2p-rpl] [I-D.ietf-roll-p2p-rpl]
Goyal, M., Baccelli, E., Philipp, M., Brandt, A., and J. Goyal, M., Baccelli, E., Philipp, M., Brandt, A., and J.
Martocci, "Reactive Discovery of Point-to-Point Routes in Martocci, "Reactive Discovery of Point-to-Point Routes in
Low Power and Lossy Networks", draft-ietf-roll-p2p-rpl-17 Low Power and Lossy Networks", draft-ietf-roll-p2p-rpl-17
(work in progress), March 2013. (work in progress), March 2013.
[I-D.ietf-roll-trickle-mcast] [I-D.ietf-roll-trickle-mcast]
Hui, J. and R. Kelsey, "Multicast Protocol for Low power Hui, J. and R. Kelsey, "Multicast Protocol for Low power
and Lossy Networks (MPL)", draft-ietf-roll-trickle- and Lossy Networks (MPL)", draft-ietf-roll-trickle-
mcast-09 (work in progress), April 2014. mcast-11 (work in progress), November 2014.
[I-D.thubert-6lowpan-backbone-router] [I-D.thubert-6lowpan-backbone-router]
Thubert, P., "6LoWPAN Backbone Router", draft-thubert- Thubert, P., "6LoWPAN Backbone Router", draft-thubert-
6lowpan-backbone-router-03 (work in progress), February 6lowpan-backbone-router-03 (work in progress), February
2013. 2013.
[I-D.sarikaya-core-sbootstrapping] [I-D.sarikaya-core-sbootstrapping]
Sarikaya, B., Ohba, Y., Moskowitz, R., Cao, Z., and R. Sarikaya, B., Ohba, Y., Moskowitz, R., Cao, Z., and R.
Cragie, "Security Bootstrapping Solution for Resource- Cragie, "Security Bootstrapping Solution for Resource-
Constrained Devices", draft-sarikaya-core- Constrained Devices", draft-sarikaya-core-
skipping to change at page 13, line 44 skipping to change at page 13, line 33
Phinney, T., Thubert, P., and R. Assimiti, "RPL Phinney, T., Thubert, P., and R. Assimiti, "RPL
applicability in industrial networks", draft-phinney-roll- applicability in industrial networks", draft-phinney-roll-
rpl-industrial-applicability-02 (work in progress), rpl-industrial-applicability-02 (work in progress),
February 2013. February 2013.
8.3. External Informative References 8.3. External Informative References
[IEEE802154e] [IEEE802154e]
IEEE standard for Information Technology, "IEEE std. IEEE standard for Information Technology, "IEEE std.
802.15.4e, Part. 15.4: Low-Rate Wireless Personal Area 802.15.4e, Part. 15.4: Low-Rate Wireless Personal Area
Networks (LR-WPANs) Amendament 1: MAC sublayer", April Networks (LR-WPANs) Amendment 1: MAC sublayer", April
2012. 2012.
[IEEE802154] [IEEE802154]
IEEE standard for Information Technology, "IEEE std. IEEE standard for Information Technology, "IEEE std.
802.15.4, Part. 15.4: Wireless Medium Access Control (MAC) 802.15.4, Part. 15.4: Wireless Medium Access Control (MAC)
and Physical Layer (PHY) Specifications for Low-Rate and Physical Layer (PHY) Specifications for Low-Rate
Wireless Personal Area Networks", June 2011. Wireless Personal Area Networks", June 2011.
[OpenWSN] "Berkeley's OpenWSN Project Homepage", [OpenWSN] "Berkeley's OpenWSN Project Homepage",
<http://www.openwsn.org/>. <http://www.openwsn.org/>.
skipping to change at page 21, line 47 skipping to change at page 21, line 26
communication. This is done by building the schedule with dedicated communication. This is done by building the schedule with dedicated
cells in such a way that at most one node communicates with a cells in such a way that at most one node communicates with a
specific neighbor in each slotOffset/channelOffset cell. Multiple specific neighbor in each slotOffset/channelOffset cell. Multiple
pairs of neighbor nodes can exchange data at the same time, but on pairs of neighbor nodes can exchange data at the same time, but on
different frequencies. different frequencies.
B.2. Multi-Channel vs. Channel Hopping B.2. Multi-Channel vs. Channel Hopping
A TSCH schedule looks like a matrix of width "slotframe size", S, and A TSCH schedule looks like a matrix of width "slotframe size", S, and
of height "number of frequencies", nFreq. For a scheduling of height "number of frequencies", nFreq. For a scheduling
algorithm, these can be considered atomic "units" to schedule. In algorithm, cells can be considered atomic "units" to schedule. In
particular, because of the channel hopping nature of TSCH, the particular, because of the channel hopping nature of TSCH, the
scheduling algorithm should not worry about the actual frequency scheduling algorithm should not worry about the actual frequency
communication happens on, since it changes at each slotframe communication happens on, since it changes at each slotframe
iteration. iteration.
B.3. Cost of (continuous) Synchronization B.3. Cost of (continuous) Synchronization
When there is traffic in the network, nodes which are communicating When there is traffic in the network, nodes which are communicating
implicitly re-synchronize using the data frames they exchange. In implicitly re-synchronize using the data frames they exchange. In
the absence of data traffic, nodes are required to synchronize to the absence of data traffic, nodes are required to synchronize to
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2. Lower slotframe identifiers take precedence over higher slotframe 2. Lower slotframe identifiers take precedence over higher slotframe
identifiers. identifiers.
In the example above, the node would transmit to node B on slotframe In the example above, the node would transmit to node B on slotframe
2. 2.
Authors' Addresses Authors' Addresses
Thomas Watteyne (editor) Thomas Watteyne (editor)
Linear Technology Linear Technology
30695 Huntwood Avenue 32990 Alvarado-Niles Road, Suite 910
Hayward, CA 94544 Union City, CA 94587
USA USA
Phone: +1 (510) 400-2978 Phone: +1 (510) 400-2978
Email: twatteyne@linear.com Email: twatteyne@linear.com
Maria Rita Palattella Maria Rita Palattella
University of Luxembourg University of Luxembourg
Interdisciplinary Centre for Security, Reliability and Trust Interdisciplinary Centre for Security, Reliability and Trust
4, rue Alphonse Weicker 4, rue Alphonse Weicker
Luxembourg L-2721 Luxembourg L-2721
LUXEMBOURG LUXEMBOURG
Phone: +352 46 66 44 5841 Phone: +352 46 66 44 5841
Email: maria-rita.palattella@uni.lu Email: maria-rita.palattella@uni.lu
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