What is the function of the Presentation Layer of the OSI model?

The Presentation Layer is responsible for data translation (formatting), compression, and encryption.

The Presentation Layer is primarily concerned with translation; interpreting and converting the data from various formats. For example, EBCIDIC characters might be converted into ASCII. It is also where data is compressed for transmission and uncompressed on receipt. Encryption techniques are implemented at the Presentation Layer.

The redirector operates at the presentation layer by redirecting I/O operations across the network. Common protocols that operate at the presentation layer include SMB, NCP, & NFS.