Exercise 1
1. Present some types of network that are popular such as MAN,
WAN, LAN and so on
 What is a WAN?
A wide-area network (WAN) is the technology that connects your offices, data centers, cloud
applications, and cloud storage together. It is called a wide-area network because it spans beyond a
single building or large campus to include multiple locations spread across a specific geographic
area, or even the world. For example, businesses with many international branch offices use a WAN
to connect office networks together. The world’s largest WAN is the internet because it is a collection
of many international networks that connect to each other. This article focuses on enterprise WANs
and their uses and benefits.
 What is a metropolitan area network (MAN)?
A metropolitan area network (MAN) is a computer network that connects computers within a
metropolitan area, which could be a single large city, multiple cities and towns, or any given
large area with multiple buildings. A MAN is larger than a local area network (LAN) but smaller
than a wide area network (WAN). MANs do not have to be in urban areas; the term
"metropolitan" implies the size of the network, not the demographics of the area that it serves.
 What is a Local Area Network?
A LAN is a computer network that consists of access points, cables, routers, and switches that
enable devices to connect to web servers and internal servers within a single building, campus,
or home network, and to other LANs via Wide Area Networks (WAN) or Metropolitan Area
Network (MAN). Devices on a LAN, typically personal computers and workstations, can share
files and be accessed by each other over a single Internet connection.
A router assigns IP addresses to each device on the network and facilitates a shared Internet
connection between all the connected devices. A network switch connects to the router and
facilitates communication between connected devices, but does not handle Local Area Network
IP configuration or sharing Internet connections. Switches are ideal tools for increasing the
number of LAN ports available on the network.
2. Present some common protocols like: TCP/IP, HTTP, DNS, DHCP, ICMP
and so on

What is TCP/IP?
TCP/IP stands for Transmission Control Protocol/Internet Protocol and is a suite of
communication protocols used to interconnect network devices on the internet. TCP/IP is also
used as a communications protocol in a private computer network (an intranet or extranet).
 How does TCP/IP work?
TCP/IP uses the client-server model of communication in which a user or machine (a client) is
provided a service, like sending a webpage, by another computer (a server) in the network.
Collectively, the TCP/IP suite of protocols is classified as stateless, which means each client
request is considered new because it is unrelated to previous requests. Being stateless frees up
network paths so they can be used continuously.
3. What is HTTP?
 (HyperText Transfer Protocol) The communications protocol used to connect to Web
servers on the Internet or to servers on a local network if an intranet is used. The
primary function of HTTP is to establish a connection with the server and send HTML
pages back to the user's browser. It is also used to download data from the server either
to the browser or to any requesting application that uses HTTP .
 A Stateless Connection
HTTP is a "stateless" request/response system. The connection is maintained between
client and server only for the immediate request, and the connection is closed. After the
HTTP client establishes a TCP connection with the server and sends it a request command,
the server sends back its response and closes the connection.
The first version of HTTP caused considerable overhead. Each time a graphics file on the
page was requested, a new protocol connection had to be established between the browser
and the server. In HTTP Version 1.1, multiple files could be downloaded with the same
connection. It also improved caching and made it easier to create virtual hosts (multiple
websites on the same server). See HTTP/2, HTTP header and cookie.