Protected information system link utilizing tunneling, security controls, and endpoint address translation giving the impression of a dedicated line.
Sources:
NIST SP 1800-21B
under Virtual Private Network
from
CNSSI 4009-2015
NIST SP 800-53 Rev. 5
under virtual private network
from
CNSSI 4009-2015
A virtual network built on top of existing networks that can provide a secure communications mechanism for data and IP information transmitted between networks.
Sources:
NIST SP 800-113
under Virtual Private Network