DSR vs AODV
Dynamic Source Routing (DSR) and AdHoc On Demand Distance Vector Routing (AODV) are both routing protocols for wireless mesh/ad hoc networks. Both the protocols employ different mechanisms that result in varied performance levels. DSR and AODV can be compared and evaluated based on the packet delivery ratio, normalized MAC load, normalized routing load, and average end-to-end delay by altering the number of sources, speed, and pause time.
Both DSR and AODV are demand-driven protocols which form a route on demand when a transmitting computer desires a route. The main difference between DSR and AODV is the source routing feature. The DSR is based on source routing in which all the routing information such as is maintained at the mobile nodes. The DSR computes the routes and also updates them. The source routing is a technique in which the packet sender identifies the entire sequence of the node into which the packet has to pass through. The packet sender lists the route in the packet’s header so that the next node to which the packet has to be transmitted can be identified by the address on the way to the destination host. The AODV uses a combination of a DSR and DSDV mechanism. It uses the route discovery and route maintenance from a DSR and hop-by-hop routing, periodic advertisements, sequence numbers from DSDV. The AODV easily overcomes the counting to infinity and Bellman Ford problems, and it also provides quick convergence whenever the ad hoc network topology is altered.
When DSR and AODV are analyzed using a packet delivery ratio parameter by varying the paused time in the intervals of 0, 10, 20, 40, 100, the results obtained for both on demand routing protocols look similar.
The normalized routing load is analyzed for both protocols by varying paused times. The values for the DSR protocol were less as compared to the AODV which show fairly stable results even after increasing the number of sources. If normalized routing load is stable, the protocol is considered to be scalable. The routing overhead for AODV is mainly from the route requests. DSR finds the route in the cache as a result of aggressive caching. This helps to avoid a frequent route discovery process in DSR thereby decreasing the routing overhead for DSR when compared to AODV.
The normalized MAC load is analyzed by varying different paused times. The values for AODV is less when compared to DSR when analyzed for lower paused times.
When it comes to performance comparison between the two protocols, the cache staleness and high MAC overhead degrade the performance of DSR in high mobility scenarios. In lower-mobility scenarios, the performance of DSR is better than AODV as the route is always found quickly in cache avoiding the route discovery process.
Summary:
1. DSR has less routing overhead than AODV.
2. AODV has less normalized MAC overhead than DSR.
3. DSR is based on a source routing mechanism whereas AODV uses a combination of
DSR and DSDV mechanisms.
4. AODV has better performance than DSR in higher-mobility scenarios.
5. DSR has less frequent route discovery processes than AODV.