The impact of mobility and node capacity on voice traffic

MANET is one of the wireless networks in which interest is growing due to its flexibility, scalability and non-infrastructure status which is characterized by dynamically distributed clusters of nodes that have the ability to communicate locally and with the Internet. Voice over MANET-IP has become an attractive and popular application. This paper investigates the voice traffic application over the Ad Hoc on Demand Vector reactive routing protocol for different mobility models. The simulation evaluation using OPNET demonstrates the advantage of the Global System for Mobile Communication voice codec over the Internet using the UDP/IP protocol. The voice signaling and the Session Initiation IP (SIP) application layer protocols were tested and compared using different parameters. Different scenarios of mobility and node capacities were considered to test Quality of Service indicators including end-to-end delay, jitter, throughput, load, mean opinion score of voice quality, traffic sent and received, control signals, physical locations of calling nodes and the number of hops. The results showed that using the voice signaling produced better performance in respect of delays when compared to the SIP session. Voice has performed better when compared to the three mobility models with slightly less throughput and longer delays when considering the very fast mobility model. The node capacity showed serious impact on all performance metrics when MANET capacity exceeds 50 nodes in general.