V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

NNI
       Network Node Interface (ATM)


V.E.R.A. -- Virtual Entity of Relevant Acronyms (February 2016):

NNI
       Network to Network Interface


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

Network Node Interface
NNI

    (NNI) The ATM Forum's specification for
   connections between network nodes.  NNI makes network
   routing possible.  It typically refers to backbone trunk
   connections between ATM switching equipment.

   See also: UNI.

   (2001-03-26)