A document that regulates the security-related aspects of a proposed link between an agency and an external system. It regulates the security interface between any system operating under two separate authorities. It contains a large amount of descriptive, technical, procedural and planning information. Typically, it is preceded by a formal Memorandum of Understanding defining senior roles and responsibilities in managing a cross-sectoral link. Source(s): CNSSI 4009-2015 This guide has entered into an agreement between organizations that own and operate connected computer systems in order to document the technical requirements of interconnection. The ISA also supports a Memorandum of Understanding or Agreement (MOU/A) between organizations. Source(s): NIST SP 800-47 under Interconnection Security Agreement (ISA) Comments on the presentation and functionality of the glossary should be sent to email@example.com. Comments on some definitions should be sent to the authors of the linked source publication. For NIST publications, there is usually an email in the document….