Lesson 9

In this module you learned:

1. How to describe the different layers in the TCP/IP protocol
2. The rules governing IP address classes and netmasks

The protocol stack used on the Internet is the Internet Protocol Suite. It is usually called TCP/IP after two of its most prominent protocols, but there are other protocols as well. The TCP/IP model is based on a five-layer model for networking. From bottom (the link) to top (the user application), these are the physical, data link, network, transport, and application layers. Not all layers are completely defined by the model, so these layers are filled in by external standards and protocols. The layers have names but no numbers, and although sometimes people speak of Layer 2 or Layer 3 these are not TCP/IP terms. Terms like these are actually from the OSI Reference Model. The TCP/IP stack is open, which means that there are no secrets as to how it works. There are open systems too, but with TCP/IP, the systems do not have to be open and often are not. Two compatible end-system applications can communicate regardless of their underlying architectures, although the connections between layers are not defined.

1. 10BaseT: A variant of Ethernet which allows stations to be attached via twisted pair cable.
2. Backbone: The top level in a hierarchical network. Stub networks and transit networks which connect to the same backbone are guaranteed to be interconnected.
3. Ethernet: A LAN developed by Xerox in 1976. Ethernet became a widely implemented network from which the IEEE 802.3 standard for contention networks was developed. It uses a bus topology and the original Ethernet relies on CSMA/CD to regulate traffic on the main communication line.
4. (FDDI) Fiber Distributed Data Interface: FDDI is a 100 Mbit/s ANSI standard local area network architecture.It is based on optical fibre (though it can be copper cable, in which case it may be called CDDI).
5. File Transfer Protocol (FTP): Protocol used to transfer data over a network.
6. Hypertext Transfer Protocol (HTTP): Hypertext Transport Protocol defines how messages are formatted and transmitted over the Web and how Web browsers should respond to those messages.
7. Local Network (LAN): Local Area Network. A collection of computers and other hardware components linked by physical cabling that permits any device on the network to interact with any other device.
8. Point-to-point protocol (PPP): A protocol for connecting to the Internet. PPP provides error checking and compression of the IP and TCP headers.
9. Protocol stack: A layered set of protocols which work together to provide a set of network functions.
10. Router: A device used to connect networks of different types, such as those using different architectures and protocols. Routers work at the Network layer of the OSI model. This means they can switch and route packets across multiple networks. They do this by exchanging protocol-specific information between separate networks. Routers determine the best path for sending data and filter broadcast traffic to the local segment.
11. Serial port: A connector on a computer to which you can attach a serial line connected to peripherals which communicate using a serial (bit-stream) protocol.
12. TCP/IP: TCP/IP is the network protocol suite used by the Internet and most local area networks.
13. UDP: User Datagram Protocol - A connectionless datagram service in the Transport layer used by applications that typically transmit small quantities of data.
14. WAN - Wide Area Network: A network that extends over distances greater than one mile.

In this module, we introduced the following terms:

Click the Quiz link below to take a short multiple-choice quiz on the material covered in this module.
Transport Layer - Quiz