A real-time communication service for ATM-based distributed systems

We present a real-time communication service suitable for distributed systems built over ATM networks. This service offers end-to-end quality of service guarantees, and supports end-to-end priority inheritance. Prioritized handling of user messages is performed in each communication layer crossed, including the ATM level. Our service relies on a specific real-time ATM adaptation layer (AAL), that grants to preempt the transmission of a low priority message by a higher priority one. A transport service, in charge of admission control, resource reservation and connection setup is also presented. The real-time transport (RT-transport) service is implemented in the Chorus distributed operating system, as servers running in the microkernel address space. A real-rime interprocess communication (IPC) service runs over the RT-transport service. It offers location transparency to distributed communicating processes, and is designed to deal with deadline scheduling requirements. Our communication architecture allows communication user rates up to 130 Mbps over 155 Mbps ATM links. The end-to-end transfer delay is less than 400 μs