Delta-Reliability

This paper presents a new, non-binary measure of the reliability of broadcast algorithms, called Delta-Reliability. This measure quantifies the reliability of practical broadcast algorithms that, on the one hand, were devised with some form of reliability in mind, but, on the other hand, are not considered reliable according to the ``traditional'' notion of broadcast reliability [HT94]. Our specification of Delta-Reliability suggests a further step towards bridging the gap between theory and practice in the reliability of broadcast algorithms. We illustrate the use of Delta-Reliability through two case studies, namely Bimodal Multicast and IP Multicast.