data link layer
data link level
layer 2

    Layer two, the second lowest layer in the OSI
   seven layer model.  The data link layer splits data into
   frames (see fragmentation) for sending on the physical
   layer and receives acknowledgement frames.  It performs error
   checking and re-transmits frames not received correctly.  It
   provides an error-free virtual channel to the network layer.
   The data link layer is split into an upper sublayer, Logical
   Link Control (LLC), and a lower sublayer, Media Access
   Control (MAC).

   Example protocols at this layer are ABP, Go Back N,
   SRP.

   (1995-02-14)