Inleiding Telematica 6 16 mei 2007 Prof. Dr. R.J. Meijer.
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Transcript of Inleiding Telematica 6 16 mei 2007 Prof. Dr. R.J. Meijer.
Inleiding Telematica6
16 mei 2007
Prof. Dr. R.J. Meijer
Organisatorisch
Sheets asap op site– www.science.uva.nl/~rmeijer
Graag emailadres 0653720517 [email protected]
http://gene.science.uva.nl/~bbruin/
College 6, 24 mrt 2005InleidingGeen boek
Application Program Interface (API) Sockets zijn interfaces
naar de TCP/IP protocol stacks op een computer
Applicaties worden “op” sockets gebouwd
Maar vrijwel niemand doet dat nu nog
Men gebruikt – Webservers– Applicatie Servers
die een groot (ste) gemene deel van Server ontwikkeling aanbieden
TCP
IP
HTTP
HTTP
Application
Application
Groningen 5
Traditional Future
Technologies for information exchange
Technologies for the abstraction of individual
computers – aka middleware
Contemporary
Technologies for information exchange
DNA
sequencerDB 3d
Super
computer
Workstation
Technologies to use the facilities of others
Presentation
Session
Transport
Link
Data Link
Physical
Application
OSI
Specifications of protocols between computers and/or
telecommunication systems
Telematics
Middleware
Application
Virtual Computer
computercomputer computer
Technologies for the abstraction of individual
computers – aka middleware
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
XML
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
i
i
i
i
i
Teaspoon Software
Online
internet
Computer Program
i
Proxy of the teaspoon Proxy of the
Aggregation
Proxy of the teaspoons
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
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
Groningen
Sensoren (en actuatoren) zullen overal aanwezig zijn. Op dit moment staan vooral de zelforganiserende draadloze (uitstrooibare) senornetwerken in de belangstelling
10
SENSORWEB AND SENSOR NETWORKS
What is a sensor?
PopularPopular
ScientistScientist
BusinessBusiness
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
What is a sensor web?
PopularPopular
ScientistScientist
BusinessBusiness
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 Sensor Network Routing
Romit Roy Choudhury and
Pradeep Kyasanur(Some slides are based on Dr. Nitin Vaidya’s tutorial)
CS252/HillLec 8.1
2/14/02
Wireless Sensor Networks
Lecture 8 – CS252
What is a sensor network?
PopularPopular
ScientistScientist
BusinessBusiness
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 Application
Application
Sensor Network Routing
Romit Roy Choudhury and
Pradeep Kyasanur(Some slides are based on Dr. Nitin Vaidya’s tutorial)
A Review of Current Routing Protocols for Ad Hoc Mobile Wireless Networks
Elizabeth M Royer, Chai-Keong Toh
Mobile Ad Hoc Wireless Networks
• Unreliable wireless medium• Mobile nodes• No central authority
• Traffic patterns application specific• Energy constraints
• More information in MANET Charter
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
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
Classification (cont.)
Ad Hoc Routing Protocols
Table driven Source-initiated
on-demand DSDV WRP
AODV DSR TORA ABR
SSR
ReactiveProactive
Hybrid
ZRP
Hybrid
OLSR
CGSR
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
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
DSDV Example
Destination Next Metric Seq. Nr
A A 0 A-550
B B 1 B-102
C B 2 C-588
D B 3 D-312
AB C D
Routing Table of Node A
Route information is exchanged periodically
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
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
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
Source-Initiated On-Demand Routing
• Create routes only when needed
• Routes found using a “route discovery” process
• Route maintenance procedure used to repair routes
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
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
EducationPro environmentgroupsOil company Government
Information publishing
Processing data to create information
Data gathering
Research institutes
Common infrastructure
Groningen
NETWERK EN IT WORDEN OBJECTEN!
WAT NU ALS DE ICT ZELF EEN RESOURCE IS?
30
Nu: Telefonie- en internet infrastructuur: groot complex, statisch. Nu: Telefonie- en internet infrastructuur: groot complex, statisch.
PoP2
IP
PAN
kabelverdeelkast
SANTAN
PoP1
NRCNRC ISP
Internet
NRCNRC
EVKC EVKC
EVKC EVKC
EVKC
ADSLDSLAM 25 EVKC
2000 NRC 30 miljoen klanten 20000 werknemers
32Storage
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
Network
Element
Application
NE
Application
NE
Application
NC
ACNetwork
Element
Application
NE
Application
NE
Application
ACNetwork
Element
Network
Element
AC AC
NC NC NC
Virtualization of a network in UPVN
- 33 -
NE Service
ApplicationComponent
manager
IP Router / Forwarding engine
IngressPacketFilter
EgressPacketFilter
Application Component Collection
ACAC
ACAC
NC
CollectionSupport
AC packet injection 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
UPVN allows the results of decades of computer science to handle the complexities of application specific networking.
04/11/23- 35 -
Virtualized Network Service
Webservices Collection
Network Component Collection
NE NE NE
Network Utility Service
TokenTransactio
n
Uniform
CostSearch
Topology
NC NC NC
Mathematica
Use of Mathematica’s Combinatorica package to interact with real networks
04/11/23- 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:
demonstratie
Als netwerken objecten worden dan
• Verdwijnt de C uit ICT• Telematica wordt Informatica!