A multi-layered model for survivability in intra-LATA transport networks

The intra local access and transport area (LATA) transport network is modeled into four layers: the switched layer, the cross-connect layer, the multiplex layer, and the physical layer. Capacity provided to meet demand at a given layer in turn becomes demand for the next lower layer. Thus, survivability provided for a subnetwork at a given layer protects the demand originating at that layer as well as higher layer subnetworks. The author defines the layered model, gives a general characterization of survivability restoral methods, and then compares principal existing and proposed methods at each layer, especially the cross-connect layer. In particular, he discusses routing efficiency, speed, control architectures, feasibility, and potential integration with other operations functions, such as demand provisioning, network operations, customer control, and network planning