Review of microscopic and macroscopic routing algorithms in Opportunistic Networks

Opportunistic networks are highlighted with long latency and unstable network topology. It is a unique wireless network architecture which enables the mobile nodes to have communication with each other in environment where there is no continuous route between source and destination. In this network scenario there is no continuous routing path exist between source and destination. Using intermediate nodes information is conveyed to the destination. These networks espouse capture - move-forward behavior arising from the mobility of the mobile nodes for message relying. In this article we explicate about the challenges of the opportunistic networks, classification of routing protocols, also confer about the metrics required for the performance measurement of routing algorithms. For the message transfer, routing requires information about the neighborhood nodes. Based on routing behavior, we classify routing protocols as social zero information schemes and social aware information schemes. Social aware information schemes are further classified into microscopic schemes and macroscopic schemes depending upon content of the information. In this paper we discuss some of recent microscopic and macroscopic routing protocols and also confer the comparison among the reviewed algorithms.