Abstract: Using communication opportunities generated from nodes’ moving, mobile delay tolerant networks (MDTN) can offer high usability wireless communication services with low cost in non-fully-connected networks. A general MDTN architecture (GMA) is proposed in this paper. In GMA, MDTN is divided into five layers, which are application layer, assembly layer, forwarding layer, link management layer, and device layer. This architecture focuses on the effective utilization of communication opportunities, which includes the analysis of mobility model, the fast finding of adjacent neighbors and trajectory forecasting, the efficient forwarding of data packets and the creation of possible communication opportunities. Based on GMA, users can use the general interfaces of application layer to create useful MDTN applications. In urban environment, the networks formed by mobile buses are naturally special cases of MDTNs, which have a number of promising advantages including large coverage and fixed trajectory. Hence, it is suitable for urban information gathering and dissemination. Based on GMA, a 3-tier network framework is proposed for the bus-based MDTN and then some key issues are concretely studied. Several schemes are proposed including smart Internet access, fair-aware data gathering, geographic data dissemination, and buffer management and scheduling. Based on real world experiments and traces, extensive evaluations are carried out, which show that the proposed architecture and schemes perform efficiently with high robustness.