Internship end

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Presentation of internship subject, reached objectives and future work. Subject : Border router solution in Wireless Sensors Networks, running on the Contiki OS.

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Internship end

  1. 1. 6LoWPAN border router : Internship Maxime D ENIS UMONS 6 December 2012 ´Masters : Sebastien DAWANS Director : Pr. Bruno Q UOITIN Laurent D ERU Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 1 / 41
  2. 2. SummaryOutline1 Introduction2 Evaluation phase3 Implementation4 Using the testbed5 Contiki on Linux6 Master thesis7 Conclusion Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 2 / 41
  3. 3. Introduction Internship subjectStarting pointCETIC border router prototypeThe CETIC border router interconnects a WLAN (IPv6) and a WSN(6LoWPAN) using RPL for routing. F IGURE 1 : The border router in a typical topology.ModesRouter, hybrid bridge and full bridge. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 3 / 41
  4. 4. Introduction Internship subjectPhases of the internship 1 Documentation : a state of the art ; b documentation of the current implementation. 2 Evaluation : a scenarios : use cases with sequence diagrams ; b performance ; c mobility ; d etc. 3 Implementation : a optimizations ; b adding functionalities. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 4 / 41
  5. 5. Introduction Internship subjectPlatformsF IGURE 2 : Redwire Econotag [1] and ENC28J60[2] Ethernet controller (left),Crossbow Telos B [3] (right).Configuration Redwire Econotag running the CETIC BR application and an UDP server on Contiki ; Crossbow Telos B running a simple webserver (Sky websense) and an UDP sender on Contiki. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 5 / 41
  6. 6. Introduction Internship subjectTestbed F IGURE 3 : CETIC testbed topology allowing multi-hop routing. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 6 / 41
  7. 7. Introduction Notions6LoWPAN and RPL6LoWPAN[4, 5]Constitutes an adaption layer between IPv6 and IEEE 802.15.4. Itintroduces packets fragmentation and reassembly, headercompression and Link layer forwarding (in case of mesh undernetworks).RPL [6, 7]Lightweight distance vectorprotocol destined to WSN. Itbuilds a DODAG [8]representing the network.RPL performs a covering ofthe NDP functionalities(Messages : DIO, DIS, DAO). F IGURE 4 : Example of RPL DODAG. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 7 / 41
  8. 8. Introduction NotionsContikiDescriptionReal time operating system [9], for embedded platforms. Contiki madeto use only one interface : introduction of a Packet Filter.What Contiki brings uIP stack : small IPv6 (or IPv4) compliant stack, few RAM ; Protothreads : light threads stackless (blockable). F IGURE 5 : Changes between standard IPv6 stack and 6LoWPAN stack. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 8 / 41
  9. 9. Introduction CETIC prototypeStructure and modes 1 Packet filter : difference between WSN and ethernet RPL data ; 2 Full bridge mode : switch, uIPv6 forward and translating ll-addresses ; PacketFilter 3 Hybrid bridge mode : switch, ND proxy and multi-hop (in ENC28J60 802.15.4 route-over) ; 4 Router : Prefix announcement, routing, forwarding (twoF IGURE 6 : CETIC prototype separated subnets).structure. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 9 / 41
  10. 10. Introduction CETIC prototypeStructure and modes 1 Packet filter : difference between WSN and ethernet RPL data ; 2 Full bridge mode : switch, uIPv6 forward and translating Translation ll-addresses ; PacketFilter 3 Hybrid bridge mode : switch, ND proxy and multi-hop (in RPL ENC28J60 802.15.4 Traffic route-over) ; Data 4 Router : Prefix announcement, Traffic routing, forwarding (twoF IGURE 6 : CETIC prototype separated subnets).structure. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 9 / 41
  11. 11. Introduction CETIC prototypeStructure and modes 1 Packet filter : difference between WSN and ethernet RPL data ; Multi-hop ND-Proxy 2 Full bridge mode : switch, uIPv6 forward and translating Translation ll-addresses ; PacketFilter 3 Hybrid bridge mode : switch, ND proxy and multi-hop (inNDP RPLMessages ENC28J60 802.15.4 Messages route-over) ; Data 4 Router : Prefix announcement, Traffic routing, forwarding (twoF IGURE 6 : CETIC prototype separated subnets).structure. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 9 / 41
  12. 12. Introduction CETIC prototypeStructure and modes 1 Packet filter : difference between WSN and ethernet RPL data ; Routing Multi-hop 2 Full bridge mode : switch, Table uIPv6 forward and translating Translation ll-addresses ; PacketFilter 3 Hybrid bridge mode : switch, ND proxy and multi-hop (inNDP RPLMessages ENC28J60 802.15.4 Messages route-over) ; Data 4 Router : Prefix announcement, Traffic routing, forwarding (twoF IGURE 6 : CETIC prototype separated subnets).structure. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 9 / 41
  13. 13. Evaluation phaseOutline1 Introduction2 Evaluation phase Example of basic scenario The restart Sensors mobility Transparent gateway3 Implementation4 Using the testbed5 Contiki on Linux6 Master thesis Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 10 / 41
  14. 14. Evaluation phaseOrganization of the evaluation phase F IGURE 7 : Flowcharts of the evaluation phase.During the phase 1 Twelve scenarios defined and explained in documentation, declined in the three modes of the border router ; 2 When a issue was encountered, solutions were designed to improve prototype. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 11 / 41
  15. 15. Evaluation phase Example of basic scenarioDescription F IGURE 8 : Actors of the scenario.In a one-sensor topology with border router in hybrid bridge andmanual configuration 1 Wait for the DODAG to be built (typically when a DAO is received by the border router) ; 2 Plug the computer to the border router ; 3 Start sending pings to the sensor and wait for response. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 12 / 41
  16. 16. Evaluation phase Example of basic scenarioResults Computer BR 802.15.4 Sky (router) User DAD(fe80::250:c2a8:cb76:d81b) 1 DAD(fe80::250:c2a8:cb76:d81b) DAD(fe80::250:c2ff:fea8:ced0) DAD(fe80::250:c2ff:fea8:ced0) DAD(aaaa::250:c2a8:cb76:d81b) DIO NS(aaaa::212:7400:1465:f55e) NA DIO DAO Computer connection Ethernet DAD(fe80::223:dfff:fe97:2492) RA(bbbb::/64) DAD(bbbb::223:dffff:fe97:2492) Ping to Sky NS(bbbb::100) NA 13s Echo Request(seq=0) before Echo Reply(Seq=0) F IGURE 9 : Ping from Computer to Sensor (Sky) through the border router. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 13 / 41
  17. 17. Evaluation phase Example of basic scenarioResults Computer BR 802.15.4 Sky (router) User DAD(fe80::250:c2a8:cb76:d81b) DAD(fe80::250:c2a8:cb76:d81b) DAD(fe80::250:c2ff:fea8:ced0) DAD(fe80::250:c2ff:fea8:ced0) DAD(aaaa::250:c2a8:cb76:d81b) DIO NS(aaaa::212:7400:1465:f55e) NA DIO DAO 2 Computer connection Ethernet DAD(fe80::223:dfff:fe97:2492) RA(bbbb::/64) DAD(bbbb::223:dffff:fe97:2492) Ping to Sky NS(bbbb::100) NA 13s Echo Request(seq=0) before Echo Reply(Seq=0) F IGURE 9 : Ping from Computer to Sensor (Sky) through the border router. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 13 / 41
  18. 18. Evaluation phase Example of basic scenarioResults Computer BR 802.15.4 Sky (router) User DAD(fe80::250:c2a8:cb76:d81b) DAD(fe80::250:c2a8:cb76:d81b) DAD(fe80::250:c2ff:fea8:ced0) DAD(fe80::250:c2ff:fea8:ced0) DAD(aaaa::250:c2a8:cb76:d81b) DIO NS(aaaa::212:7400:1465:f55e) NA DIO DAO Computer connection Ethernet DAD(fe80::223:dfff:fe97:2492) RA(bbbb::/64) Ping to Sky DAD(bbbb::223:dffff:fe97:2492) NS(bbbb::100) 3 NA 13s Echo Request(seq=0) before Echo Reply(Seq=0) F IGURE 9 : Ping from Computer to Sensor (Sky) through the border router. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 13 / 41
  19. 19. Evaluation phase The restartBridge in autoconf mode restarting in stable networkIssue encounteredWhen restarting, the border router requests a DODAG (using a DISmessage) and a prefix on the wired network. If it receives a DIO first, itbecomes leaf and root at the same time : loop.F IGURE 10 : DODAG representation of the network before and afterrestarting. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 14 / 41
  20. 20. Evaluation phase The restartSolutionChanges to implementation Increment the version number of the DODAG : the incremented number makes the network restarting ; Construct a prefixless DODAG (using link-local address as DODAG ID instead of global address) in autoconfiguration mode ; When a prefix is received from the wired network, add it to the DIO (in Prefix Information Option) and propagate it.Changes to ContikiThe prefix treatment in a sensor already in a DODAG was defectiveand had to be modified to handle new prefix announced. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 15 / 41
  21. 21. Evaluation phase Sensors mobilityLoss in wireless sensors networksHow can a loss occur ? Sensor problem, interferences, collisions ; Moving topology.F IGURE 11 : DODAG representation of the network before and after a sensorloss.Deal with lossesLosses in WSN can occur a lot of time : ETX metric used in RPL. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 16 / 41
  22. 22. Evaluation phase Sensors mobilityLoss in wireless sensors networksHow can a loss occur ? Sensor problem, interferences, collisions ; Moving topology.F IGURE 11 : DODAG representation of the network before and after a sensorloss.Deal with lossesLosses in WSN can occur a lot of time : ETX metric used in RPL. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 16 / 41
  23. 23. Evaluation phase Sensors mobilityLoss in wireless sensors networksHow can a loss occur ? Sensor problem, interferences, collisions ; Moving topology.F IGURE 11 : DODAG representation of the network before and after a sensorloss.Deal with lossesLosses in WSN can occur a lot of time : ETX metric used in RPL. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 16 / 41
  24. 24. Evaluation phase Sensors mobilityDealing with lost destinationsBefore implementationThe lifetime attribute of the route is used. When lifetime expires, theassociated route is tested and can be removed from the table. Thismechanism prevent any kind of quick mobility among several subnets.ProposalUse the ETX for descending routes, and remove routes when somecondition are encountered : The ETX of the neighbor becomes greater than a threshold value ; No-ack penalties are encountered. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 17 / 41
  25. 25. Evaluation phase Transparent gatewayBridge mode to simplify subnets F IGURE 12 : Several subnets visible as one subnet with bridge.Issue encountered with full bridgeOn-link prefix announced as off-link, and poorly propagated. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 18 / 41
  26. 26. ImplementationOutline1 Introduction2 Evaluation phase3 Implementation4 Using the testbed5 Contiki on Linux6 Master thesis7 Conclusion Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 19 / 41
  27. 27. ImplementationFeatures added 1 On-link prefix management and propagation (bit set and correctly managed by the sensor) ; 2 Incremented DODAG version number correctly managed by the sensors when restart ; 3 Prefix Information Option propagation and management by the sensors ; 4 Route Information Option management by the border router. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 20 / 41
  28. 28. ImplementationRoute Information Option managementOption of NDP’s RA message[10] used to set routes in routing tables. Type Length Pref Len R P R Route lifetime Prefix (variable length)F IGURE 13 : Route Information Option message format as specified in [10].Before implementationBorder router managing RA but ignoring RIOs.After implementationWhen a RIO is received from an IPv6 router, announced prefixes areadded to the routing table of the border router, and not spread to theWSN. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 21 / 41
  29. 29. Using the testbedOutline1 Introduction2 Evaluation phase3 Implementation4 Using the testbed Application Evaluation5 Contiki on Linux6 Master thesis7 Conclusion Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 22 / 41
  30. 30. Using the testbed ApplicationScenarioTwo applications 1 UDP client running on the sensors, and sending to a server frequent messages identifying them (each 15s) ; 2 UDP server running on the border router, sending an acknowledgment when receiving a message from a node. F IGURE 14 : Testbed topology used for the scenario. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 23 / 41
  31. 31. Using the testbed EvaluationMetricsWhat is measured ? PRR from testbed to server : the amount of messages (UDP packets) sent is compared to the amount of messages received at the UDP server (running on the border router) ; PRR from server to testbed : the amount of messages Acknowledgment sent by the server compared to the amount of messages received on the sensors ; TCPIP forwarding : the amount of forwards done at each sensor ; CSMA : the amount of CSMA errors encountered at each sensor and through time.How ?The packet trip is observable using traces all along the stacks (in theapplication, in the uIP stack and in CSMA). Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 24 / 41
  32. 32. Using the testbed EvaluationResults F IGURE 15 : Metrics. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 25 / 41
  33. 33. Using the testbed EvaluationResults F IGURE 15 : Metrics. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 25 / 41
  34. 34. Using the testbed EvaluationResults F IGURE 15 : Metrics. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 25 / 41
  35. 35. Using the testbed EvaluationAnalysisPRRs Metric Average value PRRTB→S 99.75% PRRS→TB 98.01% TABLE 1 : Average results of metrics.RPL is optimized for collecting data (ascendant traffic).TCPIP forwardingNodes T2 and T3 used for forwarding by T8 and sometimes by T5. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 26 / 41
  36. 36. Using the testbed EvaluationRPL routingRPL is an asymmetric routing protocol which relies on a sink systemfor ascendant traffic and on routes for descendant traffic.From sensor to border routerThe current implementationuses the default router toforward the packet.From border router to sensorA lookup is performed to findthe best route to forward thepacket. F IGURE 16 : Example of traffic on a RPL DODAG. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 27 / 41
  37. 37. Using the testbed EvaluationRPL routingRPL is an asymmetric routing protocol which relies on a sink systemfor ascendant traffic and on routes for descendant traffic.From sensor to border routerThe current implementationuses the default router toforward the packet.From border router to sensorA lookup is performed to findthe best route to forward thepacket. F IGURE 16 : Example of traffic on a RPL DODAG. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 27 / 41
  38. 38. Using the testbed EvaluationRPL routingRPL is an asymmetric routing protocol which relies on a sink systemfor ascendant traffic and on routes for descendant traffic.From sensor to border routerThe current implementationuses the default router toforward the packet.From border router to sensorA lookup is performed to findthe best route to forward thepacket. F IGURE 16 : Example of traffic on a RPL DODAG. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 27 / 41
  39. 39. Contiki on LinuxOutline1 Introduction2 Evaluation phase3 Implementation4 Using the testbed5 Contiki on Linux6 Master thesis7 Conclusion Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 28 / 41
  40. 40. Contiki on LinuxSuccessful portage of the Contiki’s app to LinuxPlatformBeaglebone using a 700Mhz ARM Cortex A8 [11], relying on theAngstrom distribution [12]. RADVD RPL .... BR Linux Server TAP IP Tables Eth Telos Beaglebone Eth SLIP RAW802.15.4 Raw or Ctrl (MAC, channel, Ack...) F IGURE 17 : Linux portage and platform structure. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 29 / 41
  41. 41. Master thesisOutline1 Introduction2 Evaluation phase3 Implementation4 Using the testbed5 Contiki on Linux6 Master thesis Subject Concrete applications7 Conclusion Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 30 / 41
  42. 42. Master thesis SubjectSubjectWhat ? Multiple border router problematic : maintain a state between several border router ; Make border router more simple : using on an higher root (outside the RPL network, in WPAN).Why ? Redundancy or Traffic engineering ; Run several QoS ; Invisible sink changes (mobility). Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 31 / 41
  43. 43. Master thesis Concrete applicationsRedundancy paths and traffic engineeringLoad balancing, robustness, etc.F IGURE 18 : One QoS on same subnet : one instance and several DODAGs. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 32 / 41
  44. 44. Master thesis Concrete applicationsRedundancy paths and traffic engineeringLoad balancing, robustness, etc.F IGURE 18 : One QoS on same subnet : one instance and several DODAGs. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 32 / 41
  45. 45. Master thesis Concrete applicationsSeveral QoSCollecting data, request data, energy-saving paths, etc., on samenetwork F IGURE 19 : Two QoS on same subnet : several instances. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 33 / 41
  46. 46. Master thesis Concrete applicationsSeveral QoSCollecting data, request data, energy-saving paths, etc., on samenetwork F IGURE 19 : Two QoS on same subnet : several instances. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 33 / 41
  47. 47. Master thesis Concrete applicationsInvisible sink changesSame QoS on two separated subnets. F IGURE 20 : Invisible mobility. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 34 / 41
  48. 48. Master thesis Concrete applicationsInvisible sink changesSame QoS on two separated subnets. F IGURE 20 : Invisible mobility. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 34 / 41
  49. 49. ConclusionOutline1 Introduction2 Evaluation phase3 Implementation4 Using the testbed5 Contiki on Linux6 Master thesis7 Conclusion Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 35 / 41
  50. 50. ConclusionInternship achievements 1 Increased border router stability : some optimizations and bugfixes ; 2 Paper : State of the art (the border router solutions) ; Complete description of the border router and scenarios detailed. 3 Features added : Border router more easily deployable ; Autoconfiguration ; Stability increased.Master thesis perspectives 1 RPL root outside WSN ; 2 Mobility, redundancy, traffic engineering. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 36 / 41
  51. 51. ConclusionQuestions ? Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 37 / 41
  52. 52. ConclusionDemonstration F IGURE 21 : Configuration.SummaryBorder router web interface, pings, etc. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 38 / 41
  53. 53. References[1] “Redwire Econotag.” http://redwirellc.com/store/node/1 (last access : 26/09/12).[2] “ENC28J60.” http://www.microchip.com/wwwproducts/ Devices.aspx?dDocName=en022889 (last access : 26/09/12).[3] Crossbow, “Telos b.” http://www.xbow.jp/TelosbCatalog.pdf (last access : 1/10/12).[4] “6LoWPAN Backbone Router.” http://tools.ietf.org/ html/draft-thubert-6lowpan-backbone-router-02 (last access : 2/10/12).[5] L. M. Ara, “Neighbor Discovery Proxy-Gateway for 6LoWPAN-based Wireless Sensor Networks.” KTM Information and Communication Technology. Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 39 / 41
  54. 54. References[6] “RFC 6550 : RPL : IPv6 Routing Protocol for Low-Power and Lossy Networks.” https://datatracker.ietf.org/doc/rfc6550/ (last access : 2/10/12).[7] J.-P. Vasseur and A. Dunkels, Interconnecting smart objects with IP. Morgan Kauffman, 2012.[8] S. Kuryla, “RPL : IPv6 Routing Protocol for Low power and Lossy Networks.” http://cnds.eecs.jacobs-university.de/ courses/nds-2010/kuryla-rpl.pdf (last access : 20/09/12), 2010.[9] “Contiki 2.6 Doxygen.” http://contiki.sourceforge.net/docs/2.6/ (last access : 17/09/12). Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 40 / 41
  55. 55. References[10] “RFC 4191 : Default Router Preferences and More-Specific Routes.” https://datatracker.ietf.org/doc/rfc4191/ (last access : 11/10/12).[11] “Beaglebone flyer.” http://beagleboard.org/static/flyer_latest.pdf (last access : 3/12/12).[12] “Angstrom distribution.” http://linuxtogo.org/gowiki/AngstromManual (last access : 3/12/12). Maxime D ENIS (UMONS) 6LoWPAN border router : Internship 6 December 2012 41 / 41

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