You will often see the terms client and server used in this
document. They are normally fairly specific terms but in this document I have
generalised their definitions a little so that they mean the following:
The machine or program that initiates an action or a connection for the purpose of gaining use of some service or data.
The machine or program that accepts incoming connections from multiple remote machines and provides a service or data to those.
These definitions are not very reliable either, but they provide a means of distinguishing the ends of peer to peer systems such as SLIP or PPP which truly do not actually have clients and servers.
Other terms you will see are:
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.
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.
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 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 and the datagram will be fragmented there. Typical values are 1500 bytes for an ethernet interface, or 576 bytes for a SLIP interface.
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 window is the largest amount of data that the receiving end can accept at a given point in time.
The route is the path that your datagrams take through the network to reach their destination.
This is an acronym for the Address Resolution Protocol and this is how a network machine associates an IP Address with a hardware address.