WordNet (r) 3.0 (2006):

network topology
    n 1: the configuration of a communication network [syn:
         topology, network topology]

The Free On-line Dictionary of Computing (30 December 2018):

network topology

    The "shape" of a network, how the nodes are
   connected to each other.  Common topologies are bus network,
   star network and ring network.

   (2009-07-16)