Service Discovery in Heterogeneous Wireless Networks TNO Physics - - PowerPoint PPT Presentation

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service discovery in heterogeneous wireless networks
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Service Discovery in Heterogeneous Wireless Networks TNO Physics - - PowerPoint PPT Presentation

Feb 26, 2024 169 likes •309 views

International Workshop on Wireless Ad-hoc Networks Service Discovery in Heterogeneous Wireless Networks TNO Physics and Electronics Laboratory MJ Blange, IP Karkowski, BCB Vermeulen 2 June 2004 1 Overview Possible approaches to

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2 June 2004 MJ Blange, IP Karkowski, BCB Vermeulen 1

TNO Physics and Electronics Laboratory

Service Discovery in Heterogeneous Wireless Networks

International Workshop on Wireless Ad-hoc Networks

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IWWAN, 2 June 2004 IP Karkowski 2

Overview

  • Possible approaches to handling vertical handovers.
  • SPEARS architecture.
  • Service discovery concepts in SPEARS.
  • Implementation details.
  • Experimental results.
  • Conclusions and future work.
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IWWAN, 2 June 2004 IP Karkowski 3

Vertical handovers

  • Lower levels of the OSI protocol stack.
  • IP layer.
  • Middleware layer between networking protocols and

application.

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IWWAN, 2 June 2004 IP Karkowski 4

LAN

The SPEARS architecture

Current implementation based on:

  • Within IMT: Bluetooth (PAN)
  • Between IMT’s: WiFi ad-hoc network (LAN)
  • Public network: GPRS (WAN)

GPRS basisstation WAN PAN PAN PAN PAN

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IWWAN, 2 June 2004 IP Karkowski 5

Motivation

  • Robustness
  • No central server
  • Flexibility of the network configuration.
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IWWAN, 2 June 2004 IP Karkowski 6

Service discovery middleware

  • Services
  • Lookup servers
  • Global lookup server (WAN)
  • Local lookup servers (LAN)
  • Registration of services
  • Usage of services

SERVICE PROVIDER SERVICE REQUESTER FIND SERVICE REGISTRY SERVICE REGISTRY SERVICE DESCRIPTION INTERACT PUBLISH SERVICE PROVIDER REQUESTER SERVICE PROVIDER REQUESTER FIND PUBLISH SERVICE DESCRIPTION SERVICE CLIENT FIND PUBLISH SERVICE DESCRIPTION SERVICE CLIENT

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IWWAN, 2 June 2004 IP Karkowski 7

Service / Network Outage (Case 1)

LAN WAN

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IWWAN, 2 June 2004 IP Karkowski 8

Service / Network Outage (Case 2)

WAN LAN

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IWWAN, 2 June 2004 IP Karkowski 9

Service / Network Outage (Case 3)

WAN

LAN

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IWWAN, 2 June 2004 IP Karkowski 10

SPEARS Implementation of Service Discovery

Essential requirements:

  • Multicasting support.
  • Restricting multicast to LAN.
  • Routing of IP packages between mobile nodes

through WAN. Highlights:

  • Combination of AODV & Mobile IP.
  • Based on Jini™ from Sun Microsystems.
  • SPEARS specific extensions.
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IWWAN, 2 June 2004 IP Karkowski 11

Implementation aspects

  • ‘Codebase’ problem - must be different in WAN and

LAN registrations.

  • SpearsClassLoader
  • setCodebase() member function.
  • First register at WAN, then LAN.
  • Service type identification - applications must be able

to see which service version (LAN or WAN) they are about to use.

  • Services annotated with an attribute indicating service type.
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IWWAN, 2 June 2004 IP Karkowski 12

Experimental results

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IWWAN, 2 June 2004 IP Karkowski 13

Conclusions

  • Vertical handovers at middleware layer.
  • Practical implementation in Jini.