Hybrid checkpoint protocol for supporting mobile-to-mobile communication

Some information systems consist of mobile stations and fixed stations. Mission critical applications are required to execute fault-tolerance in these systems. However, the mobile stations support neither enough volume of storage, processing power nor battery capacity to provide reliable communication and computation. Thus, it is difficult for multiple mobile stations to synchronously take checkpoints. We propose a hybrid checkpointing protocol where mobile stations take asynchronously and fixed ones take synchronously checkpoints. In addition, mobile stations store messages into logs for making the local states consistent with checkpoints taken by fixed stations. For supporting wireless LAN protocols such as IEEE 802.11 and HIPERLAN, messages are stored into a log in a mobile support station without exchanging additional messages even with mobile-to-mobile communication