A computer network connects two or more devices to share files, video chat, surf the web, use instant messaging, email, voice calls, and transmit multiple forms of traffic. The network has physical hardware components, software services, end devices that interface with users, intermediary devices that connect individual networks, and transmission media like copper, fiber optic, or wireless cables. Servers provide information to clients using software like web servers and browsers, email servers and mail clients, and file servers accessed by software such as Windows Explorer.

2.  Defining a Network
 A (computer) network is an interconnection of two or more computing devices.
 It can serve a variety of purposes including:
 File sharing between two computers
 Video chatting across different parts of the world
 Surfing the Web
 Instant messaging (IM) between computer with IM software installed.
 E-mail
 Voice over IP (VoIP)
 A converged network is one that transports multiple forms of traffic (video, voice,
and data)

4. The network components are:
• The physical elements, or hardware such as a laptop, switch, router,
wireless access point, the cabling used to connect the devices, … etc.
• The services,called software, that provide information in response to
a request like email hosting
services and web hosting services.

5. • End Devices or Hosts: These devices form the interface between users and the underlying
communication network. Examples of end devices are Computers (work stations, laptops, file
servers, web servers), Network printers, VoIP phones, Mobile handheld devices, and … etc.
– A host device is either the source or destination of a message transmitted over the network.
• Intermediary Network Devices: Intermediary devices connect the individual hosts to the
network and can connect multiple individual networks to form an internetwork. Examples of
intermediary devices are switches, wireless access points, routers, firewalls, and … etc.
– These devices use the destination host address to determine the path that messages should
take
through the network.
• Network Media: The medium provides the channel over which the message travels from
source to destination. The three types of media are Copper, Fiber Optic, and Wireless.

17.  Servers are computers
with software that
enable them to provide
information, like email
or web pages, to other
end devices on the
network. Each service
requires separate server
software.

18.  Clients are computer with software installed
that enable them to request and display the
information obtained from the server.

19.  Web Client and Servers: The Web Server
runs web server software and clients use
their browser software , such Windows
Internet Explorer, to access web pages on
the server.

20.  Email Client and Server: The Email Server runs
email server software and clients use their
mail client software, such as Microsoft
Outlook, to access email on the server.

21.  File Client and Server: The File Server stores
corporate and user files in a central location.
The client devices access these files with
client software such as Windows Explorer.