Communication networks are traditionally assumed to be connected. However, in delay and disruption tolerant networks(DTN), there are many unconventional difficulties, such as intermittent connectivity, large delay and may never have an end-to-end contemporaneous path, a node has to store-and-carry messages for a long time, until a new forwarding opportunity arises. Because every node needs to store message, content storage becomes the core service of the DTNs, we can implement a content-based forwarding. This paper proposes a new data dissemination method, which classifies the forwarding messages by their content, every node only requests the message that it is interested in. So the messages transmitted in the network can be cut down largely. Of course, in order to improve delivery rate, nodes also request and store messages that requested by other nodes they have contacted with. Meanwhile, the paper adopts a buffer management scheme based on content popularity, a node manages its buffer depending on the times that messages are requested, when the buffer has no adequate capacity, firstly deletes the message that is requested the least. Simulation experiments illustrate that this method can provide low overhead while maintaining high delivery rate and low delivery latencies compared to epidemic routing.
