Host, Workstation, and Server

Host, Workstation, and Server

Networks are made up of lots of different components, but the three most common network

entities are the host, workstation, and server. For the Network+ exam, you need a good understanding

of these three primary components of a network. Each one of these items can be found

on most networks.

Understanding Workstations

In the classic sense, a

workstation

is a powerful computer used for drafting or other math-intensive

applications. The term is also applied to a computer that has multiple central processing

units (CPUs) available to users. In the network environment, the term

workstation

normally

refers to any computer that is connected to the network and used by an individual to do work.

It is important to distinguish between workstations and clients. A

client

is any network entity

that can request resources from the network; a workstation is a computer that can request

resources. Workstations can be clients, but not all clients are workstations. For example, a

printer can request resources from the network, but it is a client, not a workstation.

Understanding Servers

In the truest sense, a server does exactly what the name implies: It provides resources to the clients

on the network (“serves” them, in other words). Servers are typically powerful computers

that run the software that controls and maintains the network. This software is known as the

network operating system.

Servers are often specialized for a single purpose. This is not to say that a single server can’t

do many jobs, but, more often than not, you’ll get better performance if you dedicate a server

to a single task. Here are some examples of servers that are dedicated to a single task:

•  File Server

Holds and distributes files.

•  Print Server

Controls and manages one or more printers for the network.

•  Proxy Server 

Performs a function on behalf of other computers. (Proxy means “on behalf of.”)

•  Application Server

Hosts a network application.

•  Web Server

Holds and delivers web pages and other web content using the Hypertext Transfer Protocol (HTTP).

• Mail Server

Hosts and delivers e-mail. It’s the electronic equivalent of a post office.

•   Fax Server 

Sends and receives faxes (via a special fax board) for the entire network without the need for paper.

•  Remote Access Server 

Listens for inbound requests to connect to the network from the outside.
Remote access servers provide remote users (working at home or on the road) with a connection
to the network, either via modems or an IP connection.

• Telephony Server

 Functions as a “smart” answering machine for the network. It can also perform

call center and call-routing functions.

Notice that each server type’s name consists of the type of service the server provides (remote

access, for example) followed by the word server, which, as you remember, means to serve.

Regardless of the specific role (or roles) these servers play, they should all have the following

in common:

_ Hardware and/or software for data integrity (such as backup hardware and software)

_ The capability to support a large number of clients

Figure 1.1, earlier in this chapter, shows a sample network. Physical resources, such as harddrive

space and memory, must be greater in a server than in a workstation because the server

needs to provide services to many clients. Also, a server should be located in a physically secure

area. Figure 1.2 shows a sample network that includes both workstations and servers. Note that

there are more workstations than servers because a few servers can serve network resources to

hundreds of users simultaneously.

Example:

A sample network including servers and workstations

Understanding Hosts

The term host covers pretty much every other networking device, but it can also refer to a workstation

and server and is most commonly used when discussing TCP/IP-related services and

functions. In fact, a host, in TCP/IP terms, is any network device that has an IP address. Workstations,

servers, and any other network device (as long as it has one or more IP addresses) can

all be considered hosts. In conversation, you may also hear the word host used to describe any

minicomputer or server. For the Network+ exam, however, you should stick to the classic definition

used here (i.e., workstations, servers, and other network devices).

The term host comes from the era when the only intelligent devices on the network were

mainframes, which were commonly referred to as hosts regardless of TCP/IP functionality.

Nearly all other devices were known as dumb terminals, but no other device had intelligence,

only the mainframe. As TCP/IP came into the picture, only the mainframes, or hosts, received

IP addresses. This is the same era that produced the term gateway to refer to any layer 3 intermediate

device, such as a router. Just as the term gateway remains in common use today, such

as in the very common term default gateway, the term host is still used, but its use is much

broader now that nearly every end and intermediate device is intelligent and has at least one IP

address, making them hosts.