As a result of the open nature of ONA, network elements are potentially vulnerable to abuse. Network elements are analog and digital devices and supporting equipment that provide communication services such as switching, multiplexing, and transport services to subscribers. All network element interfaces and ports that accept user command inputs are potentially vulnerable to unauthorized access. Security features, such as authentication, access control, audit, integrity, and administration, are necessary to protect network elements from various types of attacks leading to misuse and abuse of the software functions within a network element. If security features are not properly conceived, designed, implemented, tested, installed, documented and maintained, vulnerabilities are likely to result.