Self Organization in Ad Hoc Networks

1. Self Organization in Ad Hoc Networks BASIL SAEED, ATTA ZAINALDIN Professor: ABDULMOTALEB EL SADDIK Course: ELG 5121 November 26, 2010

2. Outline • Overview of Ad Hoc Networks • Self organization Ad hoc Networks • Problems with self organizing ad hoc networks • ZRP Protocol • Small World graph phenomenon • Terminode Routing • Grid Routing • Comparison • Conclusion • References

3. Ad hoc Networks Overview • Local area network (LAN) that is built spontaneously as devices connect. • Instead of relying on a base station to coordinate the flow of messages to each node in the network, the individual network nodes forward packets to and from each other (act as routers). • A network can be integrated with existing infrastructure.

4. Self Organization Ad hoc Networks • Decentralized and Non-authorized networks unlike internet that has specific characteristics: • Self-healing - mechanisms that allow to detect, localize, and repair failures automatically; primarily distinguished by the cause of the failure • Self-configuration - methods for (re-)generating adequate configurations depending on the current situation in terms of environmental circumstances, e.g. connectivity, quality of service parameters • Self-management - capability to maintain devices or networks depending on the current parameters of the system • Self-optimization - similar to self-management but focuses on the optimal choice of methods and their parameters based on the system behaviour • Adaptation - adaptation to changing environmental conditions, e.g. the changing number of neighbouring nodes • Advantages: • Scalability

5. Problems with Self Organization Ad hoc Networks • There are some problems that may occur when designing a self organized ad hoc network; • Configuration • Discovery • Routing • Cooperation incentive • Security

6. Configuration • DHCP is used in the internet • DHCP cannot be used in self organizing networks • Using Mobile IP: • Designed to allow mobile device users to move from one network to another while maintaining a permanent IP address. • Adding care of address capability to DHCP • An IP address associated with mobile node that is visiting a foreign link.

7. Discovery • A node has to be discovered and located in the network Solution: 1) Global Positioning system (GPS) • Bad Signal 2) A Self Positioning Algorithm (SPA) • using the distance between nodes to form a coordinate system which is then used to locate and discover the node. • Uses time of arrival to obtain the distance between neighbors

8. Cooperation • Ad hoc networks are highly cooperative • Nodes are selfish • Nodes tend to use services provided by other nodes, but not to provide services for free to the community • There should be a way to: • Encourage users to provide services • Discourage users to from overloading the network • Cooperation incentives, i.e. Nuglet • Nuglet: Virtual Currency

9. Security • In self organized networks, the nodes are easy to be attack; • The channel is wireless • The network is decentralized • Solution • Node 1 asks for secure communication by send Cipher Suites • Node 2 chooses the strongest Cipher and notifies node 1 • Node 2 send digital certificate • Node 1 uses random number to encrypted the public key of node 2 • Node 2 decrypted the message using its private key • From the random number, both node can encrypt and decrypt the data

10. Routing Protocols • There are two routing protocol categories for ad hoc networks: • Proactive Routing Protocols: maintain routing information independently of need for communication i.e. OLSR • Reactive Routing Protocol: discover route only when you need itresearchers chose i.e. AODV

11. Cont. • OLSR Protocol: • a HELLO message which is used to discover the information about the link status and the host’s neighbours • Topology Control message which is used to send information all over the network about the node’s neighbours

12. Cont. • Pros. • Low latency, suitable for real-time traffic • Cons. • Bandwidth might get wasted due to periodic updates

13. Cont. • AODV protocol contains 3 type of messages; • Route Request message (RREQ) • Route Reply message (RREP) • Route Error message (RERR) • Source node uses an expanding ring search technique to establish a route to the destination node. 13

14. Cont. • Pros. • Saves energy and bandwidth during inactivity • Less overheads which are needed to track the route from the source to destination nodes. • It responds fast in the topological changes, and updates only the nodes that are involved in this change using RRER. • Cons. • Significant delays may occur as a result of route discovery 14

15. ZoneRoutingProtocol • Hybrid routing protocol uses both combination of proactive and reactive routing protocols • Uses reactive (inter-zone) and proactive (intra-zone) routing protocols to maintain routes • Nodes use intra-zone routing protocol to maintain local routing tables to neighbours • Nodes use inter-zone routing protocol to communicate with nodes outside of their zone

16. Cont. Inter Zone Routing Intra Zone Routing Zone Radius = 2

17. How ZRP works • If destination is in same zone, the data is delivered directly • If in different zone, source broadcasts Route Request to all nodes of its zone • If destination is in border node’s zone, border node responds with Route Reply • Source forwards data to appropriate border node to reach destination

18. Cont. E C G H S D B A

19. Advantages and Disadvantages Advantages: • The amount of the data stored in each node is smaller than using a pure table-driven routing resulting in a faster protocol than using a pure reactive routing protocol. • Can use single and multipath Disadvantages: • Large overhead than proactive and reactive protocols • If there are many zone overlaps, redundant Route Request messages are flooded through the network (waste of Bandwidth) • Large delay due to the procedure of discovering the route from source to destination (reactive/inter-zone) • Not applicable for multimedia applications

20. Regular Graph vs. RandomGraph - Low characteristic path length - High characteristic path length - High degree of clustering. - Low degree of clustering.

21. Small World Graph • Low characteristic path length • High degree of clustering. • Two types of routing protocols which use Small World Graph: • Terminode Routing • GRID Routing

22. Terminode Routing • Every Terminode uses two Addresses for Identification: 1) End System Unique Identifier (EUI): Permanent Address. 2) Location Dependent Address (LDA): Temporary Address. - LDA address is obtained either by: a) GPS (Global Positioning System). b) No GPS (Self Positioning Algorithm SPA)

23. Cont. • Packet forwarding is done using two routing categories: • Terminode Local Routing (TLR): • Uses to reach the destination Distance Vector Intra Zone Routing (Proactive) in ZRP via EUI permanent addresses without using location information • Terminode Remote Routing (TRR): • Uses to reach the destination the geographical location (LDA), which consists of • Friend Assisted Path Discovery (FAPD) • Anchored Geodesic Packet Forwarding (AGPF) • Path Maintenance • Multipath Routing • TRR is perform until some node finds destination to be between 2 hops, from there on, only TLR is used

24. Anchored Geodesic Packet Forwarding (AGPF) • Allow data to be sent to remote terminode based on locations of node • Data be sent along the Anchored path • Anchored path is the route from source to destination and provided with a list of Anchore • Anchore point describe the geographical coordinates (LDA) • Good Anchore: Path that avoids obstacles and un-useful terminodes from source to destination S D

25. Other elements • Friend assisted path discovery • This method is used to obtain the Anchore paths • The Terminode may contact its friends in order to find an Anchored path to the destination of interest • Path maintenances • Allows a Terminode to improve the acquired paths • Multipath routing • Maintain several paths to a single destination

26. GPS and SPA • Global Positioning system (GPS) • Nodes know their geo coordinates • Route to move packet closer to end point • Propagate geo info by flooding • Not efficient with bad signals • A Self Positioning Algorithm (SPA) • Using the distance between nodes to form a coordinate system which is then used to locate and discover the node. • Uses time of arrival to obtain the distance between neighbors

27. GRIDRouting • Divide the physical into squares called grids, with increasing the size of the grid • Server location: Each Node selects location servers in each of the three sibling squares in each level • Ex: Node B selects at : • Level 0: 10, 23 and 17, Level 1: 22,33 and 60 and Level 2: 19,21 and 28 Level 0 10 7 44 54 77 47 B 67 22 Location Servers 23 17 45 28 33 80 1 Level 1 88 84 60 44 34 99 27 21 Level 2 19 49 56 26 Level 3 50

28. Cont. • Packet Forwarding: Sender forwards packets using geographic forwarding to the least node greater than or equal to node desired destination ID. • Ex: A sends packets to B using servers located at 26, 19 and 7 10 7 44 54 B 77 47 67 22 23 17 45 28 33 80 1 88 84 60 44 34 27 19 21 26 62 49 56 99 32 50 90 A

29. Comparison • GRID • Hierarchical routing approach: scalable • No GPS: allows position-unaware nodes to use position-aware nodes as proxies • Simpler and less information • May Fail to find a path to destination • Terminode • Hierarchical routing approach: scalable • No GPS: SPA • Complex and more information • Always find a path to destination

30. Conclusion • Self Organization Ad hoc Networks have some specific characteristics • Small world graphs with low characteristic paths and high level of clustering can organize a model for Self Organization Ad hoc Networks • Terminode and GRID routing can solve configuration, discovery, and routing problems faced in self configured ad hoc networks • When GPS is available, GRID routing is simpler to process. • When GPS is not Available, Terminode routing is more robust and has less probability of failure. • Next step, look for solutions for cooperation and security problems

31. References [1] Chlamtac I., Conti M., Liu J. J.-N.: "Mobile ad hoc networking: imperatives and challenges". Ad Hoc Networks,Elsevier, Vol. 1, Issue 1, p. 13-64 (2003). [2] F. Dressler, "Self-Organization in Ad Hoc Networks: Overview and Classification," University of Erlangen, Dept. of Computer Science 7, Technical Report 02/06, March 2006. [3] L. Buttyán, J.-P. Hubaux, “Nuglets: a Virtual Currency to Stimulate Cooperation in Self-Organized Mobile Ad Hoc Networks,” Technical report No. DSC/2001/001, Swiss Federal Institution of Technology, Lausanne, January 2001. http://icawww.epfl.ch/hubaux/ [4] Zhijiang Chang, G. Gaydadji ev, S. Vassiliadis, "Routing Protocols for Mobile Ad hoc Networks: Current Development and evaluation.“ Computer Engineering laboratory, EEMCS, Delft University of Technology, April 2005. [5] J.Haas and M. R. Pearlman, "The Zone Routing Protocol (ZRP) for Ad Hoc Networks," IETF Internet Draft, June 1999

32. [6] Nature Publishing Grouping. “Collective dynamics of 'small-world' networks“. From http://www.nature.com/nature/journal/v393/n6684/full/393440a0.html [7] L. Blazevic, S. Giordano, J. Y. Le Boudec “Self organized terminode routing simulation“ Proceedings of ACM International Workshop on Modeling Analysis and Simulation of Wireless and Mobile systems (MSWiM 2001), Rome, Italy, July 2001 [8] L. Blazevic, S. Giordano, J. Y. Le Boudec "Anchored Path Discovery in Terminode Routing" The Second IFIP-TC6 Networking Conference (Networking 2002) Proceedings, Pisa, May 2002 [9] L. Blazevic, L. Buttyan, S. Capkun, S. Giordano, J. Hubaux, and J. Boudec,”Self-Organization in Mobile Ad-hoc Networks: The Approach of Terminodes,"IEEE Communication Magazine, vol. 39, no. 6, pp. 166{174, June 2001. [10] W.-H. Liao, Y.-C. Tseng, and J.-P. Sheu, “GRID: a fully location-aware routing protocol for mobile ad hoc networks,” Telecommunication Systems, vol. 18,no. 1, pp. 37–60, Sep. 2001. Cont.

33. Questions