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Inleiding Telematica 6 16 mei 2007 Prof. Dr. R.J. Meijer
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Organisatorisch l Sheets asap op site –www.science.uva.nl/~rmeijerwww.science.uva.nl/~rmeijer l Graag emailadres l 0653720517 l rmeijer@science.uva.nl rmeijer@science.uva.nl l http://gene.science.uva.nl/~bbruin/ http://gene.science.uva.nl/~bbruin/
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College 6, 24 mrt 2005 Inleiding Geen boek
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Application Program Interface (API) l Sockets zijn interfaces naar de TCP/IP protocol stacks op een computer l Applicaties worden “op” sockets gebouwd l Maar vrijwel niemand doet dat nu nog l Men gebruikt –Webservers –Applicatie Servers l die een groot (ste) gemene deel van Server ontwikkeling aanbieden TCP IP HTTP Application
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Groningen 5 TraditionalFuture n Technologies for information exchange n Technologies for the abstraction of individual computers – aka middleware Contemporary n Technologies for information exchange DNA sequencer DB3d Super computer Workstation n Technologies to use the facilities of others Presentation Session Transport Link Data Link Physical Application OSI n Specifications of protocols between computers and/or telecommunication systems Telematics Middleware Application Virtual Computer computer n Technologies for the abstraction of individual computers – aka middleware
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Groningen 6 Webservices (from Webservice essentials, E.Cerami) Web service Any service available over the Internet That uses a standardized XML messaging system Alternatives XML RPC (remote procedure call) SOAP HTTP Post/Get XML
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Groningen 7 Aggregation of Teaspoon proxies Web and Grid services are designed to provide on-line services Service oriented architecture Implicit object oriented, component oriented virtualization concept iiiii Teaspoon Software Online internet Computer Program i Proxy of the teaspoon Proxy of the Aggregation Proxy of the teaspoons
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Groningen 8 Object oriented virtualization … i wireless link computer and sensors i i i i i Teaspoon Software Online internet Step 1: Think and link the things Build in a computer Give that computer control Link the computers (via the Internet) Step 2: Create virtual “agent” for a group of things That offers easy, controlled, service, to many “customers” via the internet “the service of an online resource” Forget about the individual things
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Groningen 9 … where in the third step the interaction between the resources is coordinated through software, via the internet Caffeine advisor Human caffeine model Billing Software Teaspoon Software Online Telephone Company Step 3: Service integration and creation Software integrates the services and interactions of various resources into a new service
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Groningen Sensoren (en actuatoren) zullen overal aanwezig zijn. Op dit moment staan vooral de zelforganiserende draadloze (uitstrooibare) senornetwerken in de belangstelling 10
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SENSORWEB AND SENSOR NETWORKS
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What is a sensor? Popular Scientist Business A small but very intelligent device that can measure something important Intriguing telecommunication and computing devices that can solve many problems Cheap things for mass market
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What is a sensor web? Popular Scientist Business A group/swarm of small but very intelligent wireless devices that can measure something important and communicate adhoc with each other and with the sink that connects to the internet xxxxx= buzz word Intriguing telecommunication and computing devices that can solve many problems Cheap things for mass market
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What is a sensor network? Popular Scientist Business A network and very many sensor webs and several applications at several institutions Intriguing telecommunication and computing devices that can solve many problems Intelligent infrastructures Network/Internet Application
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Sensor Network Routing Romit Roy Choudhury and Pradeep Kyasanur (Some slides are based on Dr. Nitin Vaidya’s tutorial)
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A Review of Current Routing Protocols for Ad Hoc Mobile Wireless Networks Elizabeth M Royer, Chai-Keong Toh
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Mobile Ad Hoc Wireless Networks Unreliable wireless medium Mobile nodes No central authority Traffic patterns application specific Energy constraints More information in MANET Charter
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Example Ad Hoc Network B A E F H C G I D Nodes have unique identifiers Routing problem – find path between S and D S
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Classification of routing protocols Table-driven (proactive) – Up-to-date routing information maintained – Routing overhead independent of route usage Source-initiated (demand-driven / reactive) – Routes maintained only for routes in use – Explicit route discovery mechanism Hybrid Protocols – Combination of proactive and reactive
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Classification (cont.) Ad Hoc Routing Protocols Table driven Source-initiated on-demand DSDV WRP AODV DSR TORAABR SSR Reactive Proactive Hybrid ZRP Hybrid OLSR CGSR
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Table-driven Routing Protocols Each node maintains a routing table – Contains routes to all nodes in the network Changes to network topology is immediately propagated Protocols differ in mechanisms used to propagate topology information
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Destination Sequenced Distance Vector (DSDV) Based on Bellman-Ford algorithm Enhanced with sequence number to avoid loops – Fresher routes have higher sequence numbers Optimizations added to reduce routing overheads – incremental data exchange, delayed exchange of updates
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DSDV Example DestinationNextMetricSeq. Nr AA0A-550 BB1B-102 CB2C-588 DB3D-312 A B C D Routing Table of Node A Route information is exchanged periodically
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Clusterhead Gateway Switch Routing (CGSR) Nodes organized into hierarchy of clusters. Each node has a clusterhead, selected using an election. Nodes send packet through clusterheads. Clusterheads communicate amongst themselves using DSDV. – Two clusters are connected through a gateway node
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Wireless Routing Protocol (WRP) Maintains multiple tables – Distance, routing, link-cost, etc. Link change messages exchanged only between neighbors Loop freedom using novel algorithm – Uses predecessor hop information
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Other Table-Driven Protocols Optimized Link State Routing Protocol (OLSR) – RFC 3626 – Optimization of link-state routing to wireless Topology Dissemination Based on Reverse Path Forwarding (TBRPF) - RFC 3684 – Also based on link-state routing
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Source-Initiated On-Demand Routing Create routes only when needed Routes found using a “route discovery” process Route maintenance procedure used to repair routes
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Ad Hoc On-Demand Distance Vector Routing (AODV) Now RFC 3561, based on DSDV Destination sequence numbers provide loop freedom Source sends Route Request Packet (RREQ) when a route has to be found Route Reply Packet (RREP) is sent back by destination Route Error messages update routes
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Robert Meijer, TNO ICT Groningen 4G sensornetwork support telecom infrastructure 29 Shared Resources. It is good practice that sensor networks serve many applications at several institutions. Technical: this enables changes, exploitation: this shares costs Education Pro environment groups Oil company Government Information publishing Processing data to create information Data gathering Research institutes Common infrastructure
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Groningen NETWERK EN IT WORDEN OBJECTEN! WAT NU ALS DE ICT ZELF EEN RESOURCE IS? 30
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Nu: Telefonie- en internet infrastructuur: groot complex, statisch. PoP2 IP PAN kabelverdeelkast SAN TAN PoP1 NRC ISP Internet NRC EVKC ADSL DSLAM l 25 EVKC l 2000 NRC l 30 miljoen klanten l 20000 werknemers
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32 Storage Sensor networks will be large and complex too, but are dynamic. E.g. with disasters parts of the networks are destroyed and a immediate addaptation is required 4 3 1 5 2 8 6 10 9 7 11 Supercomputing Next GNG mobile fixed network nodes - RESEARCH TOPIC
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Network Element Application NE Application NE Application NC AC Network Element Application NE Application NE Application AC Network Element Network Element AC NC Virtualization of a network in UPVN - 33 -
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NE Service Application Component manager IP Router / Forwarding engine Ingress Packet Filter Egress Packet Filter Application Component Collection AC NC Collection Support AC packet injection Network elements are PC’s that run a Free BSD operating system - 34 - NE’s expose webservice interfaces AC’s are SCPed on NE AC’s communicate with application via a message passing mechanism through NE webservice interface
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UPVN allows the results of decades of computer science to handle the complexities of application specific networking. 7/26/2014- 35 - Virtualized Network Service Webservices Collection Network Component Collection NE Network Utility Service Token Transaction Uniform Cost Search Topology NC Mathematica
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Use of Mathematica’s Combinatorica package to interact with real networks 7/26/2014- 36 - Needs["WebServices`"] <<DiscreteMath`Combinatorica` <<DiscreteMath`GraphPlot` Print["The following methods are available from the NetworkComponent:",InstallService["http:// localhost:3000/network_service/service.wsdl"]]; The following methods are available from the NetworkComponent: {GetAllLinks,GetAllElements,NetworkTokenTransaction} Initialisation: n = GetAllElements[]; e = GetAllLinks[]; nids = Apply[Union,e]; Print["Network elements: ", n]; Print["Number of ports found: ", Length[nids]]; Network elements: {bigvirdot,virdot} Number of ports found: 16 NE Discovery: Topology and visualization of the shortest path: nodePath = ConvertIndicesToNodes[ ShortestPath[g, Node2Index[nids,"192.168.3.4"], Node2Index[nids,"139.63.77.49"]], nids]; Print["Path: ", nodePath]; If[NetworkTokenTransaction[nodePath, "green"]==True, Print["Committed"], Print["Transaction failed"]]; Path: {192.168.3.4,192.168.3.1,139.63.77.30,139.63.77.49} Committed Shortest path, transactions, use of tokens:
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demonstratie
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Als netwerken objecten worden dan Verdwijnt de C uit ICT Telematica wordt Informatica!
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