Forwarding Policies for Delay and Disruption Tolerant Networks

In Delay and Disruption Tolerant Networks (DTNs) [1], packet forwarding is based on the store-carry-and-forward paradigm. Basically, each node has a buffer and is able to store messages persistently, until an appropriate forwarding opportunity arises. In addition, several routing protocols for DTNs employ message replication as an alternative to increase the message delivery rate. The role of a forwarding policy for DTNs is to determine the packets a node should forward to a neighbor during a contact. Forwarding a packet, in this context, implies sending a replica and does not mean discarding it, which may lead to frequent buffer overflow. Thus, node must employ a buffer management policy to define which message should be dropped if its buffer is full. In this paper, we evaluate three well-known forwarding policies – FIFO, random, and GRTRMAX – jointly with our proposed buffer management policy named Least Recently Forwarded (LRF) [3]. Our goal is to identify the forwarding policy that is more suitable to be used with LRF.