A Congestion Avoidance Algorithm for Opportunistic Networks
Hezhe Wang, Huiqiang Wang · 2025
An opportunistic network is a mobile ad hoc network that utilizes the encounter opportunities created by node mobility to achieve message transmission between nodes. The mobility of nodes in an opportunistic network results in extremely limited storage space being carried by nodes. When the network uses a multi-copy routing protocol to forward messages, it is extremely easy for the limited storage space of nodes to be exhausted, leading to network congestion and further affecting network performance. In response to the above issues, this article proposes a congestion avoidance algorithm for opportunistic networks. The algorithm first prioritizes the messages in each node based on the number of times the messages have been replicated and further sets the storage threshold and threshold for the number of times a node receives messages for each node. Finally, the algorithm reduces the TTL of messages based on the storage threshold and threshold for the number of times a node receives messages, and determines the order in which messages are discarded when buffer overflow occurs based on the message priority. The simulation results show that the congestion avoidance algorithm not only improves the delivery ratio of the network but also reduces the delay and overhead by effectively utilizing the node buffer space.