**3. Overview of AODV, DSDV and RWMM**

#### **3.1 Ad Hoc on-demand distance vector routing (AODV)**

The AODV protocol (Perkins & Royer, 1999) is a reactive routing protocol for MANETs. It discovers routes once demanded via a route discovery process. The protocol uses route request (RREQ) packets sent by the sender node and circulating throughout the network. Each node in the network rebroadcasts the message except the sink node. The receiver replies to the RREQ message with a route reply (RREP) packet that is routed back to the sender node. The route is then cached for future reference; however in case a link is broken, a route error (RERR) packet is sent to the sender and to all the nodes as well so as to initiate a new route discovery. To maintain routing information, AODV uses a routing table with one entry for each destination. Thus, the table is used to propagate RREP to the source node. AOOV (Geetha Jayakumar & G. Gopinath, 2007, 2008) also relies on time, which means that if a routing table is not used recently, it will expire. Moreover, once a RERR is sent, it is meant to warn all nodes in the network; hence, this makes it very efficient to detect broken paths.

#### **3.2 Destination-sequenced distance vector routing (DSDV)**

The DSDV protocol (C. Perkins & P.Bhagwat, 1994) is a routing algorithm that focuses on finding the shortest paths. The protocol is based on the Bellman-Ford algorithm to find the routes with improvements. The latter algorithm is very similar to the well-known Dijkstra's algorithm with the support of negative weights. DSDV (Md. Monzur Morshed et al., 2010) falls in the proactive category of routing protocols; hence, every mobile node maintains a table containing all the available destinations, the number of hops to reach each destination, and a sequence number. The sequence number is assigned by the destination node its purpose is to distinguish between old nodes and new ones. In order for the nodes to keep track of moving other nodes, a periodic message containing a routing table is sent by each node to its neighbors. The same message can also be sent if significant change occurs at the level of the routing table. Therefore, the update of the routing table is both time-driven and event-driven. Further discussion can be done for better performance, such as not sending the whole table (full dump update), but only the modified portions (incremental update). The motivation behind it is to be able to update the rest of the network through one packet. This means that if the update requires more than one packet, a full dump is probably a safer approach in this case.

#### **3.3 Random waypoint mobility model (RWMM)**

Random Waypoint (RWP) model is a commonly used synthetic model for mobility, e.g., in Ad Hoc networks. It is an elementary model which describes the movement pattern of independent nodes by simple terms.

The Random Waypoint model (F. Bai et al., 2003; Guolong Lin et al., 2004; F.Bai & A.Helmy, 2004) is the most commonly used mobility model in research community. At every instant, a node randomly chooses a destination and moves towards it with a velocity chosen randomly from a uniform distribution [O, V max], where V max is the maximum allowable velocity for every mobile node. After reaching the destination, the node stops for a duration defined by the 'pause time' parameter. After this duration, it again chooses a random destination and repeats the whole process until the simulation ends.
