1. Routing in Ad Hoc Networks Audun Søberg Henriksen Truls Becken

2. Overview Short introduction Example of a basic routing algorithm Routing protocols IP configuring Security

3. Short introduction to wireless multihop networks Two or more nodes equipped with wireless communications and networking capability Base station is not necessary A node can communicate directly with another node that is immediately within radio range To communicate with nodes outside its own radio range an intermediate node is used to forward the packet The network is self-organizing and adaptive (autonomous distributed control is required) Nodes are able to detect the presence of other nodes and join them into the network The nodes don ’ t need to be of the same type (phone, PDA, laptop, sensor, etc.)

4. Application areas Tactical military Emergencies Disaster relief Sensor Meetings/conferences

5. Challenges Dynamic topologies Bandwidth-constrained, variable capacity links Energy-constrained Limited physical security Scalability

6. Simple routing protocol example Propagation of routing table Routing and transmitting

7. Routing table Destination terminal Next node AA BA CE DD …… Each terminal has its own routing table (in proactive routing algorithms)

8. Position notification packet ID of terminal which the created the packet Timestamp for the created packet ID of hop source terminal Hop count Contents of the packet: Used to make and update the Routing Table Broadcasted in a limited area

9. Renewal of Position Notification Packet ABD t =1t =2 t =3 t =4 A A ABAC A1A1 A1B2 A1C3 C BBCC

10. Routing A B Routing Table in D D G E I C H F To F DestNext AA BB CE D- EE FI GE HI II

11. Routing A B D G E I C H F To F Routing Table in I DestNext AD BD CC DD EE FH GE HH I-

12. Routing A B D G E I C H F To F Routing Table in H DestNext AI BI CC DI EI FF GC H- II

13. Basic transmitting procedure Request to send (RTS) Clear to send (CTS) Ready to receive (RTR)

14. Topology problem Hidden terminal problem Exposed terminal problem Busy tones

15. Ad Hoc routing protocols Proactive –Large overhead Reactive –Delay before first packet –Doesn’t scale Hybrid scheme –Clusters

16. Destination Sequenced Distance Vector (DSDV) Periodic routing Distance vector –dest, next hop, distance, seq no Two ways to update neighbors –Full dump –Incremental update

17. Dynamic Source Routing (DSR) On demand Source routing –Each packet contains full route Route discovery –Flood RREQ packets –RREP returned when route found Route maintenance –RERR when route is broken

18. Ad-hoc On-demand Distance Vector (AODV) From DSR –Route discovery –Route maintenance From DSDV –Hop-by-hop routing –Sequence numbers

19. Zone Routing Protocol (ZRP) Predefined zones –Centered around each node Proactive local routing Reactive global routing

20. IP address assignment No centralized logic Small address room in IPv4 Network splitting Network merging

21. Two approaches A leader –Responsible for all addresses Buddy system –Start with one node responsible for all addresses –Joining node gets half of the addresses from an existing node

22. Routing security vulnerabilities Open medium Dynamic topology Distributed cooperation (absence of central authorities) Constrained capability (energy)

23. Types of attacks Black hole Denial of service Routing table overflow Impersonation Energy consummation