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

network layer
layer 3

    (communications subnet layer) The third lowest
   layer in the OSI seven layer model.  The network layer
   determines routing of packets of data from sender to
   receiver via the data link layer and is used by the
   transport layer.  The most common network layer protocol
   is IP.

   (1994-12-13)