Key Terms

Review the following list of key terms:

• modular design— A design that calls for the complete system to be built from individual components that pass information across well-defined interfaces.

• Network Access layer— The layer of the TCP/IP stack that provides an interface with the physical network.

• Internet layer— The layer of the TCP/IP stack that provides logical addressing and routing.

• Transport layer— The layer of the TCP/IP stack that provides error control and acknowledgment and serves as an interface for network applications.

• Application layer— The layer of the TCP/IP stack that supports network applications and provides an interface to the local operating environment.

• header— A bundle of protocol information attached to the data at each layer of the protocol stack.

• message— In TCP/IP networking, a message is the data package passed from the Application layer to the Transport layer. The term is also used generically to describe a message from one entity to another on the network. The term doesn't always refer to an Application layer data package.

• segment— The data package passed from TCP at the Transport layer to the Internet layer.

• datagram— The data package passed from the Internet layer to the Network Access layer, or a data package passed from UDP at the Transport layer to the Internet layer.

• frame— The data package created at the Network Access layer according to the specification of the physical network.

• TCP (Transmission Control Protocol)— A Transport layer, reliable, connection-oriented protocol.

• UDP (User Datagram Protocol)— A Transport layer, nonreliable, connectionless protocol.

• IP (Internet Protocol)— The Internet layer protocol that provides logical addressing and routing capabilities.