Boundary Protection Device definition in Computer Security terms:
Definition(s): A device with appropriate mechanisms that: (i) facilitates the adjudication of different interconnected system security policies (e.g., controlling the flow of information into or out of an interconnected system); and/or (ii) provides information system boundary protection.
Source(s): CNSSI 4009-2015 (NIST SP 800-53 Rev. 4)
NIST SP 800-53 Rev. 4
reference: CSRC Glossary