Abstract
We study the problem of guaranteeing synchronous message sets with the minimum message deadline (Dmin) less than twice the Target Token Rotation Time (TTRT), i.e., Dmin < 2*TTRT, in an FDDI network. While the restriction of Dmin >= 2*TTRT on a synchronous message set is generally accepted as a necessary condition for all message deadlines to be guaranteed, our study shows that this is not always the case. Some synchronous message sets with Dmin < 2*TTRT may still be guaranteed. In this paper we show that there is no need to retain the above restriction on a synchronous message set before determining its schedulability. Furthermore, an improved version of a previously-published local synchronous bandwidth allocation scheme, with removal of this restriction, is proposed