An Adaptive Information Dispersal Algorithm for Time-critical Reliable Communication

AIDA { a novel elaboration on Michael O. Rabin's IDA 21] { is a communication protocol that uses redundancy to achieve both timeliness and reliability. In AIDA redundancy is used to tackle several crucial problems. In particular, redundancy is used to tolerate failures, to increase the likelihood of meeting tight time-constraints, and to ration (based on task priorities) the limited bandwidth in the system. AIDA is a probabilistic protocol in the sense that it does not guarantee the fullllment of hard time constraints. Instead, it guarantees a lower bound on the probability of fulllling such constraints. Such a bound could be lowered so as to satisfy any level of conndence in the timeliness and reliability of the system. In this paper we present AIDA and contrast it with traditional communication scheduling techniques used in conjunction with time-critical applications in general, and distributed multimedia systems in particular. The suitability of AIDA-based bandwidth allocation for a variety of time-critical applications is established and plans for future research experiments are mentioned.