A bandwidth efficient self-healing ring for B-ISDN

This paper examines required capacity in self-healing rings (SHRs) as a function of the protection scheme, spare bandwidth allocation, routing and the traffic demand pattern. Existing SONET bidirectional rings and proposals for B-ISDN bidirectional rings assume a fixed allocation of 50% of the available bandwidth for protection traffic. This paper presents a method of minimum spare bandwidth allocation on bidirectional rings which reduces the required capacity for both symmetric and asymmetric demand between node pairs. It is shown that a bidirectional ring with 1:1 path protection and minimum spare bandwidth allocation requires equal or less ring capacity than existing SONET SHRs for any traffic demand pattern.