Which network implements up to the presentation level and other high level services?

IBM's SNA LU6.2 is recognized for its capability to implement communication protocols that operate up to the presentation layer of the OSI model, along with providing various high-level services such as application-level support. The presentation layer is responsible for translating data formats and ensuring that data is understandable to both sender and receiver, which is fundamental in a network that facilitates complex interactions among various applications.

SNA (Systems Network Architecture) was developed by IBM and provides robust support for transaction processing and dialogue management, which can be crucial for environments requiring real-time data handling and user interaction. This makes it particularly suitable for environments where high-level data representation and interaction are necessary, thereby justifying its designation in the question.

In contrast, while SUN Microsystems's NFS (Network File System) focuses primarily on file sharing over a network, it does not extend functionality up to the presentation layer in the context suggested. Similarly, DECNET, a networking architecture developed by Digital Equipment Corporation, primarily relates to data transport and network layer functionality without focusing on high-level services or the presentation layer in the same extensive manner as SNA LU6.2.

Hence, the choice of IBM's SNA LU6.2 aligns with the requirement to encompass both presentation level operations and high