A Survey on Buffer Management Policies in Delay Tolerant Networks

Delay Tolerant Networks are the networks providing communication services where end to end delay is very long and connectivity is intermittent. In order to achieve data delivery in such challenging networking environments, researchers have proposed the use of store-carry-and-forward mechanism based protocols: there, a node may store a message in its buffer and carry it along for periods of time, until an appropriate contact opportunity arises. Additionally, multiple message replicas are often propagated to increase delivery probability. This combination of long-term storage and replication creates a high storage overhead on mobile nodes. In real world scenarios nodes are having finite buffer storage capacity. Thus, efficient buffer management policies i.e. drop and scheduling are necessary. This paper presents basic aspects of Buffer Management in terms of DTN and narrates the various policies, algorithms, advantages and disadvantages. Finally brief table is presented showing comparative studies of all existing drop and scheduling policies.