A 'fragmented' restoration scheme for flat network architectures

An escalation strategy for a flat network based on the Big Crossconnects Architecture (BCA) and discordant virtual paths is proposed. The proposed scheme implements different restoration mechanisms at the switching and transport layers of the BCA for each discordant virtual path. The switching layer mechanism is called the dormant VP protection and will combine the best characteristics of dedicated and semi-dedicated-ATM protection. The transport layer is protected using the VP link switching scheme that is a hybrid between SDH and ATM 1:1 protection mechanisms. The overall escalation is designed so that the interworking between the two mechanisms is transparent to the users.