1. Mobile Ad-Hoc Networking By Jared Roberts

2. Overview What is a MANET? What is a MANET? Problems with routing in a MANET Problems with routing in a MANET Oh Node! (laugh!) Oh Node! (laugh!) Current Solutions Current Solutions

3. What is a MANET? MANET – (Mobile Ad-Hoc NETwork) a system of mobile nodes (laptops, sensors, etc.) interfacing without the assistance of centralized infrastructure (access points, bridges, etc.) MANET – (Mobile Ad-Hoc NETwork) a system of mobile nodes (laptops, sensors, etc.) interfacing without the assistance of centralized infrastructure (access points, bridges, etc.)

4. The Problem Unstable paths Unstable paths Processing power Processing power Battery life Battery life Time delays Time delays High cost of memory High cost of memory

5. Factors Affecting MANETs Scalability Scalability Power vs. Latency Power vs. Latency Incompatible Standards Incompatible Standards Data Rates Data Rates User Education User Education Security Security Coverage Coverage

6. Solutions Table Driven Table Driven DSDV DSDV CGSR CGSR WRP WRP Source-initiated On-Demand Driven Source-initiated On-Demand Driven AODV AODV DSR DSR LMR LMR TORA TORA ABR ABR SSR SSR

7. The Family Tree

8. Destination-Sequenced Distance- Vector Routing (DSDV) Every node maintains a routing table. Every node maintains a routing table. “Full” vs. “incremental” update “Full” vs. “incremental” update Settling time – the weighted average time that routes to a destination will fluctuate before the route with the best metric is received. Settling time – the weighted average time that routes to a destination will fluctuate before the route with the best metric is received.

9. Clusterhead Gateway Switch Routing (CGSR) A central “clusterhead” node is chosen. A central “clusterhead” node is chosen. The clusterhead is chosen by the “Least Cluster Change” algorithm The clusterhead is chosen by the “Least Cluster Change” algorithm Traffic is routed to the current clusterhead who forwards the traffic through a gateway node to the next clusterhead in line until the clusterhead of the destination node is located. Traffic is routed to the current clusterhead who forwards the traffic through a gateway node to the next clusterhead in line until the clusterhead of the destination node is located. Each node must maintain a cluster member table Each node must maintain a cluster member table

10. CGSR (cont.)

11. Wireless Routing Protocol (WRP) 4 tables: Distance, routing, link-cost, and message retransmission list 4 tables: Distance, routing, link-cost, and message retransmission list Neighboring nodes broadcast update messages Neighboring nodes broadcast update messages Uses hello messages to establish connectivity Uses hello messages to establish connectivity Checks all incoming update information Checks all incoming update information

12. Comparing Table Driven Routing Protocols

13. Ad-hoc On-demand Distance Vector Routing (AODV) Route Request Packets (RREQ) Route Request Packets (RREQ) The source node broadcasts an RREQ to all neighboring nodes. The source node broadcasts an RREQ to all neighboring nodes. Nodes record the source of the first RREQ received to establish a reverse path. Nodes record the source of the first RREQ received to establish a reverse path.

14. AODV (cont.) Route Reply Packets (RREP) Route Reply Packets (RREP) The destination or node with a route to the destination unicasts a RREP back to the source to establish a route. The destination or node with a route to the destination unicasts a RREP back to the source to establish a route.

15. Dynamic Source Routing (DSR) Each node maintains a route cache. Each node maintains a route cache. If a source node has no route in its cache, it broadcasts a route request. If a source node has no route in its cache, it broadcasts a route request. A route reply is generated when either the destination or a node with a route to the destination is found. A route reply is generated when either the destination or a node with a route to the destination is found. Supports symmetric links Supports symmetric links

16. DSR (cont.) Maintenance is accomplished by route error packets and acknowledgements. Maintenance is accomplished by route error packets and acknowledgements. If a node fails to send an acknowledgement, any route that contains that node is truncated. If a node fails to send an acknowledgement, any route that contains that node is truncated.

17. Temporally-Ordered Routing Algorithm (TORA) Used in highly dynamic networks Used in highly dynamic networks Provides multiple routes for source/destination pair Provides multiple routes for source/destination pair Uses direct acyclic graphs to measure “height” Uses direct acyclic graphs to measure “height” Assumes all nodes have synchronized clocks Assumes all nodes have synchronized clocks Classifies links as upstream and downstream Classifies links as upstream and downstream

18. TORA (cont.)

19. Associativity-Based Routing (ABR) Uses degree of association stability as a metric Uses degree of association stability as a metric Strives to build “longer-lived” routes Strives to build “longer-lived” routes

20. Signal Stability Routing (SSR) Selects routes based on signal strength and location stability Selects routes based on signal strength and location stability Periodic beacons update signal strength tables Periodic beacons update signal strength tables Only requests that are received over strong channels are forwarded unless the PREF field in the header is set to allow weak channels Only requests that are received over strong channels are forwarded unless the PREF field in the header is set to allow weak channels

21. Comparing Source-Initiated On- Demand Routing Protocols