Optional Facilities

• File Transfer

• Terminal Emulation

If such facilities are provided they shall conform to the specification defined in this Chapter.

File Transfer

A NC that supports the File Transfer option shall provide access to directories and files using the protocol defined in Internet Standard 9, File Transfer Protocol:

• IETF RFC 959, File Transfer Protocol.

This protocol is carried over Transmission Control Protocol (see Transmission Control Protocol ) connections. It is implementation-defined whether and under what conditions this connection is left open.

When the URL does not specify a username, then an implementation-defined username shall be used.

When the URL does not specify a password and a password is required for access to the referenced resource, the user shall be prompted for one.

When the URL does not specify a port, port 21 shall be used.

When the url-path component of the URL refers to a directory, the names of the files in that directory shall be presented on the display.

When the url-path component of the URL refers to a file, the contents of that file shall be retrieved:

• The file's contents may be presented to the user. It is implementation-defined whether the file's name or contents can be used as an announcement mechanism to assist the product in presenting the file's contents.

• If the product supports a local or remote file system, the user shall be given the option of storing the file's contents on the file system using a name that is user-definable.

The file transfer facilities shall support the transfer of both raw (IMAGE) and translated (ASCII) format files.

Terminal Emulation

A NC that supports the Terminal Emulation option shall provide access to remote systems by terminal emulation using the Telnet protocol.

All interaction with the user shall conform to the required rendition behavior specified in Internet Standard 8, Telnet Protocol:

• IETF RFC 854, Telnet Protocol Specification

• IETF RFC 855, Telnet Option Specifications.

All communication with the remote system shall use the protocol specified in Internet Standard 8, Telnet Protocol:

• IETF RFC 854, Telnet Protocol Specification

• IETF RFC 855, Telnet Option Specifications.

The Telnet protocol shall be carried over the Transmission Control Protocol (see Transmission Control Protocol ).