Design of resilient core ATM networks

This paper examines three distinct methods of designing an ATM core network which is resilient to any single cable break (often the most common type of major failure): (1) The ATM crossconnects are collocated with SDH 4/4 crossconnects, and VPs are multiplexed onto VC-4s which are routed through the SDH crossconnect platform. Protection is at the SDH layer, with backup VC-4 routes assigned to working VC-4s. (2) As in option 1, ATM crossconnects are collocated with SDH crossconnects, and VPs are multiplexed onto VC-4s which are routed through the SDH crossconnect platform. The protection in this case is at the ATM layer, with backup VPs assigned to working VPs. (3) ATM crossconnects are collocated at SDH crossconnect sites, however the SDH crossconnects are not used for routing ATM traffic and point-to-point links transport the (single hop) VC-4s directly between ATM switches where VPs are multiplexed/demultiplexed. Protection is at the ATM layer, with backup VPs assigned to working VPs. The principal goal is to evaluate the schemes in terms of the cost required to provide resilience to ATM traffic from any single cable break.