Gruppepresentasjon

Virtual Transparent Directory withMobile Ad-Hoc Networking

Henning BergJon Oldevik

Lars Kristian Snellingen ByeMansur Ali Abbasi

Sven Jørgen Karlsen

Virtual Transparent Directory withMobile Ad-Hoc Networking

• Objectives– Learning to ”ad-hoc”– Implementing a simple solution to ad-hoc file sharing

• Approach– Reading theory; books and articles– Defining a prototype

• File Sharing on a virtual ad-hoc network– Analysing usage areas– Implementing the prototype

• Expected results– Knowledge on mobile ad-hoc networking and bluetooth…

• Technology: J2ME, Bluetooth• Usage

– An implemented prototype– Documentation of results

Mobile Ad-Hoc Networking

• About ad-hoc– Latin phrase: for this purpose

– Also: refer to an improvised and often impromptu event or solution

• In computer networking– Ad-hoc is mostly associated with wireless devices.

– Requires no base station.

– Devices discover others within range to form a network

– Connections are possible over multiple nodes

– Devices out of range can be found by forwarding

– Routing protocols provide stable connections even if nodes are moving around.

• Example: Sony's PlayStation Portable uses Ad-Hoc connection for wireless

multiplayer gaming.

MANETMANET

More about MANETs

• Self-configuring network of mobile terminals connected by wireless links

– Which form an arbitrary topology.

• The terminals are free to move randomly and organise themselves arbitrarily;

• May operate standalone or be connected to a larger (Inter)net.

• Minimal configuration and quick deployment – Natural or human-induced disasters, military conflicts,

emergency medical situations etc.

• Earliest MANETs were called packet radio networks

– Sponsored by DARPA in the early 1970s..

a short range alternative for ad-hoc

HiMoNN (Highly Mobile Network Node)• Example of ad-hoc application for tactical and rescue services etc.

Prototypeapplikasjon –Transparent Virtual Directory (TVD)

• Fildelingstjeneste der alle nodene i et ”tilfeldig” nett skal kunne dele filer med hverandre ved bruk av Bluetooth-kompatible enheter

• Skal brukes som grunnlag for resonnering om ad-hoc nettverk

• Flere problemområder knyttet til ”spontane” nettverk. Blant annet: – Master/slave-problematikk (server/klient)– Ruting– Filreplikering og eierskap av filer– Lastbalansering– Filforwarding

Virkemåte til TVDTre scenarioer som kan beskrive de fleste situasjoner (ved å kombinere disse):

1. To noder i et nett hvor ‘node A’ ønsker å laste ned to filer som befinner seg fysisk på ’node B’Tre noder i et nett hvor ‘node A’ ønsker å laste ned en fil fra ‘node B’ og en fil fra ‘node C’Tre noder i et nett hvor ’node A’ og ’node B’ er innenfor rekkevidde av hverandre, og ’node B’ og ’node C’ er innenfor rekkevidde av hverandre. ’Node A’ ønsker å laste ned en fil fra ’node C’.

Scenario 1: To noder, ’node A’ ønsker å laste ned to filer fra ’node B’

Scenario 2: Tre noder, ’node A’ ønsker å laste ned en fil fra hver av de to andre nodene i nettet

Scenario 3: Tre noder, ’node A’ ønsker å laste ned en fil fra en node som ikke er direkte tilgjengelig for ’node A’

Problemområder:

-

Master/slave-problematikk, ruting, lastbalansering og filforwarding:

- JSR82 som spesifiserer bruken av Bluetooth i J2ME-applikasjoner indikerer en master/slave-kategorisering av enheter- Mange noder i et nett kan føre til at mye av båndbredden blir brukt til kontrollpakker- Mobiler og PDAer har begrenset med prosessorkapasitet og minne, og store, tunge rutingsprotokoller kan bli et problemVi tror en reaktiv point-to-point (hop-by-hop) rutingprotokoll vil være best for TVD. En gitt rute blir funnet når den trengs Vil trolig benytte JBAN – et rammeverk som fjerner master/slave-problematikken, lastbalansering og har innebygd ruting

Problemområder:

Filreplikering og eierskap av filer

- Vil begrense oss til at kun én node i et nett kan dele ut en fil med et gitt filnavn. Andre noder som laster ned denne filen vil ikke uten videre dele denne ut

Usage areas of Ad Hoc networking

• Social services– Dating, chatting

• Work related / ”useful” areas– Emergency areas

– Military operations

– Sensor Networks

• Entertainment– Gameplay

• Information sharing– File sharing

– Streaming media services

– Commercial and sales

Usage areas of TVD

• Sharing of image and music files• Comercials / product information• Work situasions

– Document sharing

– Collecting data from nodes

Example usage scenario of TVD

• Document sharing between coworkers at a meeting:– No papers

– No possibility to forget / loose links

– Don’t need to bring a big laptop, the cell phone is enough.

BEDD (Bringing People Together)

• BEDDmates

• BEDDpic

• BEDDbay

• BEDDtalk

• BEDDfish

• BEDDbuddieshttp://www.bedd.com

Other Related Ad-Hoc Bluetooth Applications

• Mobiluck (http://www.mobiluck.com/)

– Sending messages and photos other to bluetooth users

• ProximityMail (http://www.inventop.com/index.htm)

– Group-based message sending / subscription

• MeetingPoint (http://www.net-cell.com/MP/index.html)

– Channel-based contact application (messaging)

• Freejack and sMan– ”Bluejacking” software

Bluetooth - background• Bluetooth is a wireless standard for interconnecting devices, using

short -range, low-power, inexpensive radios. – Radio: 2.4 Ghz ISM band, license-free. 79 (23) channels of 1 Mhz. Gross rate <= 1

Mbits– Original idea: To get rid of the cables between devices (similar to infrared

networks)Soon expands in scope and overlaps with WLAN and IR networks.

– 13 profiles (applications) built on stacks of more than 9 protocols.

• History:– 1994: Ericsson initiated a SIG (special interest group) together with IBM, Intel,

Nokia and Toshiba, to std. connecting mobile phones with other devices without cables.

• Named after Harald Blåtann II (940-981), a danish Viking king who unified Denmark and Norway (a brief period, between Harald Hårfagre and Olav the Saint).

– 1999: V1.0 released in 1500 pages (!). Triggers a parallell effort in IEEE 802.15, which looks at WPANs, but only std. the physical and data link layers. Purpose: Open std. managed by a neutral body.

– 2002: 802.15.1 approved by IEEE.– 2004: V2.0 Core spec. with EDR (up to 3 Mbits speed) released.– Present/Future: The two stds. will converge?

Bluetooth - architecture

• Piconet: basic building block of a Bluetooth system– One master node, and up to7 active slave nodes (up to 255 parked nodes), <= 10 meters apart. – All communication goes through the master, direct slave-slave is not possible. The slaves are fairly dumb,

basically just doing doing whatever their master tells them to do.– Technical note: a piconet is a centralized TDM system, with the master controlling the clock and allocating

time slots.

• Scatternet: interconnected piconets, via bridge nodes.

Bluetooth – protocol stack

• Service Discovery Protocol (SDP): Inquire about services, find out how to access● Object exchange (OBEX) Support “object exhanges”, basis for Synchronization Profile and File Transfer Profile.● Radio Frequency Communication (RFComm): Emulates the std. serial port (RS-232) on PCs for integration with legacy devices.● Logical link control adaptation protocol (L2CAP) Packet intf. to higher layers (m/s roles hidden at this layer), packet segmentation and reassembly. Multiplexes several logical channels over one physical link.

J2ME – Java Platform, Micro Edition

• What is it?– A set of technologies and specifications for small devices

– Small-footprint subsets of Java SE components

– Smaller virtual machine and leaner APIs targeted at consumer and embedded devices

• Why suitable for us?– Java Bluetooth API

– Open, non-proprietary standard for bluetooth application development

– Hides complexity of Bluetooth and allows focus on application development

J2ME – Java Platform, Micro Edition

Not so MICRO after all…?

JBAN – A potential pain reliever?

• Pain:– The process of forming a scatternet out of piconets is usually not dynamic and practical– The scatternets formed are not robust– Routing and network management causes a lot of headache for the developer

• Pain relief:– JBAN: a open source Java library for Bluetooth networking– Provides a new way to form an ad-hoc network at the Java application level– Allows unlimited devices to form a network dynamically– More robust networks, no distinction between master and slave nodes– Routing and network management is performed at high level

• Possible pitfalls:– JBAN is relatively new (more or less a bundle of code in jar-file)– “Released” February 2006, no documentation, no reported experiences– May require some “hacking” to make it work the way we want it to

• To use or not to use?– No pain no gain…JBAN may help increase the gain and reduce the pain– Decision: Let’s try it out!

Project status

• So far so good:– Focused on background reading and understanding the technology

and tools– Evaluated and abandoned several ideas before TVD:

• Triangular positioning of Bluetooth nodes• Solutions for crisis management / emergency warnings

– Now have a well elaborated, feasible idea: TVD– No external collaboration = free, independent development

• The path forward:– Ready to embark on coding / implementation

• Work in smaller subgroups, iterative• Testing in a Bluetooth network simulator?

– Will result in greater theoretical and practical insight into Mobile Ad-Hoc Networking and especially Bluetooth+J2ME

– If successful in implementation and testing, further development may be interesting (perhaps as a open source project)

Future of Bluetooth

• Advancements in progress– Larger range

– Higher transfer speeds

– QoS improvements

– Will become more feasible for more sophisticated use