An Experimental Peer-to-Peer E-mail System

Conventional e-mail systems are prone to problems that affect their dependability. E-mail systems operate following a "push-based" approach: the sender side server pushes the e-mails it wants to send to the corresponding receivers' servers. This approach may impose processing and storage overhead on the receiver side. This paper presents a peer-to-peer e-mail system in which messages are sent directly from senders to receivers using a "pull-based" approach. The sender stores locally all e-mails it intends to send, and notify their receivers using a global, distributed notification service. Receivers can then retrieve such notifications and decide if they want to receive the corresponding e-mails. If so, e-mails can be retrieved directly from their senders. This proposal is inspired from file sharing peer-to-peer systems, in which users locate and retrieve the contents they are looking for. A prototype was built to show the feasibility of the proposal, and experimental results show its viability.