ATM communication system, process migration method in the ATM communication system, and handover processing method

An ATM communication system has a connection setting section for controlling a plurality of ATM switches to set an n:n bidirectional ATM connection having n terminals of a plurality of constituent terminals as terminal points and using the VPI/VCI for identifying the n terminal points, and a process ID allocating section for allocating an MID as a process ID to a plurality of processes, executed by the n terminals for sending a message to the bidirectional ATM connection. The ATM communication system migrates a process executed on an arbitrary terminal to another terminal while keeping the process ID allocated to the processes. Where a dead-lock occurs due to that a process becomes a sleep state for the reason of that the bandwidth of a physical link is insufficient for executing in parallel the processes on the ATM communication system, the bandwidth of the physical link that a sleeping process occupies is intercepted to avoid a CAC dead-lock.