Chapter 14. Glossary of Terms used in this document.

This is an acronym for the Address Resolution Protocol . It is how a network machine associates an IP Address with a hardware address.

This is an acronym for Asynchronous Transfer Mode. An ATM network packages data into standard size blocks which it can convey efficiently from point to point. ATM is a circuit switched packet network technology.

This is usually the piece of software at the end of a system where the user is located. There are exceptions. For example, in the X11 window system, it is actually the server with the user and the client runs on the remote machine. The client is the program (or end) of a system that is receiving the service provided by the server. In the case of peer to peer systems such as slip or ppp, the client is taken to be the end that initiates the connection. The remote end being called is taken to be the server.

A datagram is a discrete package of data and headers which contain addresses (which is the basic unit of transmission across an IP network). You might also hear this called a `packet'.

The DLCI is the Data Link Connection Identifier. It is used to identify a unique virtual Point-to-Point connection via a Frame Relay network. The DLCI's are normally assigned by the Frame Relay network provider.

Frame Relay is a network technology ideally suited to carrying traffic that is of bursty or sporadic in nature. Network costs are reduced by having many Frame Relay customer sharing the same network capacity (and relying on them wanting to make use of the network at slightly different times).

This is a number that uniquely identifies a host in a physical network at the media access layer. Examples of this are Ethernet Addresses and AX.25 Addresses.

This is an acronym for Integrated Services Digital Network. ISDN provides a standardized means by which Telecommunications companies may deliver either voice or data information to a customers premises. ISDN is technically a circuit switched data network.

This is an acronym for an Internet Service Provider. These are organizations or companies that provide people with network connectivity to the Internet.

This is a number that uniquely identifies a TCP/IP host on the network. The address is 4 bytes long and is usually represented in what is called the "dotted decimal notation" (where each byte is represented in decimal from with dots `.' between them).

The Maximum Segment Size (MSS) is the largest quantity of data that can be transmitted at one time. If you want to prevent local fragmentation, MSS would equal MTU-IP header.

The Maximum Transmission Unit (MTU) is a parameter that determines the largest datagram than can be transmitted by an IP interface (without it needing to be broken down into smaller units). The MTU should be larger than the largest datagram you wish to transmit unfragmented. Note: this only prevents fragmentation locally. Some other link in the path may have a smaller MTU: the datagram will be fragmented at that point. Typical values are 1500 bytes for an ethernet interface, or 576 bytes for a SLIP interface.

The route is the path that your datagrams take through the network to reach their destination.

This is usually the piece of software or end of a system remote from the user. The server provides some service to one or many clients. Examples of servers include ftp, Networked File System, or Domain Name Server. In the case of peer to peer systems (such as slip or ppp ), the server is taken to be the end of the link that is called. The end calling is taken to be the client.

The window is the largest amount of data that the receiving end can accept at a given point in time.