A network of global coverage, scalable to an access capacity of hundreds of petabits per second, is configured as independent bufferless switches with spectral routers connecting edge nodes to the switches. The switches are logically arranged in at least one matrix, the spectral routers are logically arranged into a matrix of upstream spectral routers and a matrix of downstream spectral routers. Each edge node has a link to an upstream spectral router in each column of the matrix of upstream spectral routers and a link from a downstream spectral router in each row of the matrix of downstream spectral routers. Preferably, all sets of edge nodes connecting to the upstream spectral routers are selected to be mutually orthogonal. Each switch is coupled to a respective switch controller and a respective time indicator. Each switch controller entrains time indicators of a set of subtending edge nodes to enable coherent switching.