Which capability is notably absent in the IPC-2?

The capability notably absent in the IPC-2 is NIPR IFS. The IPC-2 (Interoperability Protocols and Standards) primarily focuses on ensuring effective communication and data exchange between different systems while meeting specific standards for data handling and security. While it supports features like authenticity verification, data encryption, and network interconnectivity, the integration of Non-Classified Internet Protocol Router Network Information Flow Services (NIPR IFS) is not a feature of the IPC-2 framework.

The absence of NIPR IFS indicates that the protocol does not include specific mechanisms or services that would facilitate the transfer or handling of Internet Protocol data across non-secure networks, which is critical for certain operational functions in governmental or military contexts. This distinction emphasizes the different layers or classifications that certain protocols operate under, isolating instances where more secure infrastructure is necessary. Thus, the correct identification of NIPR IFS as absent in IPC-2 highlights the limited scope of this particular interoperability protocol in relation to broader networking capabilities.