xAMp: A Multi-primitive Group Communications Service

The xAMp is a highly versatile group communications service aimed at supporting the development of distributed applications, with diierent dependability, functionality, and performance requirements. These range from unreliable and non-ordered to atomic mul-ticast, and are enhanced by eecient group addressing and management support. The basic protocols are synchronous, clock-less and designed to be used over broadcast local-area networks, and portable to a number of them. The functionality provided yields a reasonably complete solution to the problem of reliable group communication. Whilst other protocols exist that ooer similar services , we follow a new engineering approach by deriving all qualities of service from a single basic procedure. Thus, their implementation shares data structures, procedures, failure-recovery algorithms and group monitor services, resulting in an highly integrated package.