F

Flow Control
Flow control is a method of controlling the amount of frames or messages that are sent between two computer systems. Practically every data communications protocol contains some form of flow control to keep the sending computer from sending too many frames or packets to the receiving node.

Fiber Distributed Data Interface (FDDI)
FDDI protocol is used in local area networks (LANs) for connecting devices and/or workgroups at 100 megabits per second (Mbps) over fiber optic cable. FDDI is often used as a backbone for LANs.

File Transfer Protocol (FTP)
FTP is an application layer protocol used in Transmission Control Protocol/Internet Protocol (TCP/IP) networks. FTP is a program that can be used to transfer files between hosts on the Internet.

Firewall
According to the National Computer Security Association, a firewall is "a system or combination of systems that enforces a boundary between two or more networks." It is a controlled gateway between one network and another, typically between a private network and the Internet.

Frame
A frame is a unit of information transmitted across a data link. There are two types of frames, a control frame and an information frame. Control frames are used for initial setup and to manage the link. Information frames contain information from layers above the Data Link Layer.