MANETS

Justin ChampionRoom C203, Beacon BuildingTel 3292, j.c.champion@staffs.ac.uk

Content

IntroductionWhy consider thisTypes of Network Issues in transferring data

Conclusion

Why is this a consideration So far in lectures we have looked at cellular

networksThese are infrastructure based

The access points to the network never move The contents within the network will always be in the

same point The nodes once issued with a IP address will always

be connected at the same pointThe university uses a fixed infrastructure networkThe Internet is based on a known structure to

route information between points

Infrastructure Based Network

Router

COL-ACT-STA-

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CONSOLE

COL-ACT-STA-

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CONSOLE

A

B

Other Types of Networks PicoNets

These are a small network of a number of nodes communicate

Good example is Bluetooth with 1 master and 7 slaves communicating

ScatternetsA Scatternet is several Piconets sharing one

common device These are all examples of adhoc networks

Commonly know as MANETS

Scatternet

device

device

device device

device

PicoNet

device

device

device

device

PicoNet

devicedevice

device

device

PicoNet

Why is this a consideration With mobile networks the infrastructure can

changeConsider the previous diagram of a Scatternet If all devices are accessing the network through

an access point This will be fixed as a point into the network

As long as the device is within range

AdHoc networking consists of when there is no set infrastructure

These are referred to as MANET’s Mobile Ad hoc Networks (MANETS)

MANETS – why ? Why ?

By having common communication standards Allows all of the devices to communicate with each

other Wireless standards will be covered in another week

No installation required The parties communicating can get together to transfer

information No prior knowledge of each other is required No agreement or identification is needed to start the

communications

MANETS –Common use Usage

Business meeting All of the parties at the meeting can receive the presentations

being used Business details can be exchanged

Game players Come together for the game to play Afterwards then move to another group and join that game

Sensor networks Where a number of wireless nodes are distributed

Emergency Service use Allows a network to set quickly until full infrastructure can be

arranged

MANETS – $100 laptop Designed to allow educational computing

power in regions of the world that currently can not have it This should connect them to the Internet and allow

people access to resources we take for granted http://www.laptop.org/

Using a single connection to get all devices networking Each device will talk to its neighbours

http://www.silicon.com/research/specialreports/opensource/0,3800004943,39156063,00.htm

Uruguay has purchased 100,000 of these 29th Oct 07 http://news.bbc.co.uk/1/hi/technology/

7068084.stm

MANETS – Usage LANDroid

http://www.darpa.mil/ipto/solicitations/open/07-46_PIP.pdf

Generating a MANET and adjusting itself to ensure optimal communications

Hand held computer

Range

Hand held computer

Hand held computer

MANET Demo

A B

C

All Devices are in range All devices receive all communications

Sending from A to C is straightforward as no packet routing is required

Hand held computer

Range

MANET Demo

Hand held computer

Range

Hand held computer

Range

A B

C

A wants to communicate with C Packets can be sent through B

Difficulties Difficulty comes from

Routing information Finding a route through the network

Battery Life Other users could be using your limited battery

capability

Security Concerns The routing party could also be taking copies of any

data transferred

Routing in a MANET

Hand held computer

Range

Hand held computer

Range

Hand held computer

Range

CA

B

No Route from A to C !

Routing in a MANET The nature of mobile networks indicates that

nodes moveThis means that a route to a particular point may

also changeSpecial protocols are used to keep the routing

table current AdHoc routing protocols which come in two varieties

Re-active Only finds a route as and when required

Pro-Active These always search for the best or better routes

Routing in a MANET Examples of adhoc routing protocols

Complete list of all techniques en.wikipedia.org/wiki/Ad_hoc_protocol_list

Example techniques Pro-active

Wireless Routing Protocol (WRP)

Re-active Temporarily Ordered Routing Algorithm (TORA)

Routing using WRP Wireless Routing Protocol (WRP)

Is a table driven method of communicating Each of the nodes will have a table which contains all

routes in the network For WRP these are four tables, Routing, distance, route cost

and message retransmission

The method is proactive so The routes are worked out before they are needed They are constantly updated

Giving a overhead to the network and the battery of the device

Even routes which may never be needed are calculated and stored

Routing using WRP WRP operates by

Each node must send a “hello” message within a certain time-frame

If receiving nodes do not know the “hello” message node the routing table is updated of all receiving nodes

Each node will forward the list of known routes to all other neighbour nodes

Neighbour nodes are the ones within range of transmissions

The list is sent out periodically Sent out immediately in the event of a change to the

network

Routing using TORA Temporally Ordered Routing Algorithm (TORA)

Routes are only created as requiredPackets are sent out asking for the destination node

This packet is then forwarded to each neighbouring node Until the destination is found or a break is discovered

This method may produce multiple routes to a single destination

This is potentially good for load sharing

Sensor Network These are a number of nodes distributed within an area

The nodes can be any size Small would be located in a building to detect fire Large would be placed at location detecting ground movements An example from Intel is used to monitor ship vibration

http://www.intel.com/research/exploratory/sensornetwork_operation.htm They need

A source of power Battery or mains

Processing and detecting capabilities Wireless Communication to transfer the information

A good research paper on this subject http://ieeexplore.ieee.org/iel5/7384/32301/01507522.pdf?

isnumber=&arnumber=1507522, 2005 This link will only work within the university network

Sensor Network These are a number of nodes distributed within an area

Instead of a few detectors, this uses a large number of small detectors

Fire Alarm

Fire Detectors in a Building

Central Detector

Sensor(s)

Security Forwarding packets allows multiple nodes to

get access to the dataSecurity is required if the data is confidentialEasiest method is the use of Internet Protocol

Security (IPSEC) Although available for IPv4, it is now mandatory for the

use of IPv6 Either the data within the packet can be encrypted or

The entire packet can be placed inside another packet encrypting everything

Security Without security of some kind

How would you know a message is genuine Consider the fire example previously

What would stop someone from sending a spurious signal to active the fire system

Ensure your data is confidential Are you happy for node B to be able to read/store everything

you send?

A B C

Packet 1Packet 2Packet 3

Battery Mobile devices by there nature are battery

powered This gives a limited amount of power to the device

The biggest use of this power is the wireless networking Using adhoc networking some of the parties will drain the

battery without any benefit! (node B in the example below) Also throughput is limited, so if B wishes to communicate part

of the available network speed is being used It is about fair sharing of resources, with each device benefiting

A B C

Battery Power

Conclusion We have looked at

Networking models PicoNets ScatterNets MANETS

Considerations