1. MANETS Justin Champion Room C203, Beacon Building Tel 3292, j.c.champion@staffs.ac.uk

2. Content • Introduction • Why consider this • Types of Network • Issues in transferring data • Conclusion

3. Why is this a consideration • So far in lectures we have looked at cellular networks • These 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 point • The university uses a fixed infrastructure network • The Internet is based on a known structure to route information between points

4. B A Infrastructure Based Network

5. 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 • Scatternets • A Scatternet is several Piconets sharing one common device • These are all examples of adhoc networks • Commonly know as MANETS

6. Scatternet

7. Why is this a consideration • With mobile networks the infrastructure can change • Consider 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)

8. 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

9. 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

10. 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

11. MANETS – Usage • LANDroid http://www.darpa.mil/ipto/solicitations/open/07-46_PIP.pdf • Generating a MANET and adjusting itself to ensure optimal communications

12. MANET Demo • All Devices are in range • All devices receive all communications Sending from A to C is straightforward as no packet routing is required A B C

13. MANET Demo • A wants to communicate with C • Packets can be sent through B A B C

14. 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

15. Routing in a MANET B C A No Route from A to C !

16. Routing in a MANET • The nature of mobile networks indicates that nodes move • This means that a route to a particular point may also change • Special 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

17. 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)

18. 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

19. 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

20. Routing using TORA • Temporally Ordered Routing Algorithm (TORA) • Routes are only created as required • Packets 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

21. 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

22. 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

23. Security • Forwarding packets allows multiple nodes to get access to the data • Security is required if the data is confidential • Easiest 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

24. 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 1 Packet 2 Packet 3

25. 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

26. Conclusion • We have looked at • Networking models • PicoNets • ScatterNets • MANETS • Considerations