Clients And Servers; Connecting To The Internet; Protocols; How Information Travels On The Internet - Watchguard Firebox X20E User Manual

Connecting to the Internet

Clients and servers

Clients and servers are components of a network. A server makes its resources available to the network.
Some of these resources are documents, printers, and programs. A client uses the resources made
available by the server. A computer can be a server or a client, or it can be a server for some functions
and a client for other functions.
Connecting to the Internet
ISPs (Internet service providers) are companies that give access to the Internet through network con-
nections. Bandwidth is the rate at which a network connection can send data: for example, 3 megabits
per second (Mbps).
A high-speed Internet connection, such as a cable modem or a DSL (Digital Subscriber Line), is known
as a broadband connection. Broadband connections are much faster than dial-up connections. The
bandwidth of a dial-up connection is less than .1 Mbps, while a cable modem can be 5 Mbps or more.
Typical speeds for cable modems are usually lower than the maximum speeds, because each computer
in a neighborhood is a member of a LAN. Each computer in that LAN uses some of the bandwidth.
Because of this "shared-medium" system, cable modem connections can become slow when more
users are on the network.
DSL connections supply constant bandwidth, but they are usually slower than cable modem connec-
tions. Also, the bandwidth is only constant between your home or office and the DSL central office. The
DSL central office cannot guarantee a constant connection bandwidth to a web site or network.

Protocols

A protocol is a group of rules that allow computers to connect across a network. Protocols are the
"grammar" of the language that computers use when they speak to each other across a network.
The standard protocol when you connect to the Internet is the IP (Internet Protocol). This protocol is
the usual language of computers on the Internet.
A protocol also tells how data is sent through a network. The most frequently used protocols are TCP
(Transmission Control Protocol) and UDP (User Datagram Protocol).
TCP/IP is the basic protocol used by computers that connect to the Internet. You must know some set-
tings of TCP/IP when you set up your Firebox® X Edge. For more information on TCP/IP, see "Finding
your TCP/IP properties" on page 15.

How Information Travels on the Internet

The data that you send through the Internet is cut into units, or packets. Each packet includes the Inter-
net address of the destination. The packets that make up a connection can use different routes
through the Internet. When they all get to their destination, they are assembled back into the original
2 Firebox X Edge e-Series