An introduction to networking
Why use networks?
•More productive and efficient than stand-alone computer (A computer that is
not connected to other computers)
•Sneakernet: people where sneakers hwile walking computer to computer to
Types of networks
Every computer can communicate directly with every other computer. No
computer has more authority than the other.
• Simple to configure
•Less expensive to set up
•Not very flexible, as a p2p network grows larger adding or changing
elements may be difficult
•Not secure data can be easily discovered by unauthorized people
•Not practical for connecting more than a handful of computers
Uses a central computer to facilitate communication and resource sharing between
other computers knows as clients
Clients: take the form of personal computers aka as workstations
Client/server network: a network that uses a server to allow clients to share data,
data storage space and devices.
NOS (network operating system)
•Access to multiple shared resources can be centrally granted to s single
user or group of users
•Problems on the network can be monitored and fixed from one location
•Can handle heavy processing loads, fast response
•Servers can connect more than a handful of computers on a network
Lan (local area connection
A network of devices confined to a small space such as a building or office
Wan (wide area network)
A network that connects 2 or more geographically distinct LANs
Connects computers in different countries
Man (metropolitan area network)
Connects computers in different buildings
Elements common to a Client/server network
•Client: a computer on the network that requests resources or services from
another computer on a network (a client can sometimes also act as a server)
•Server: a computer on the network that manages shared resources; servers
usually have more processing power, memory and hard disc space than clients.
They run network operating systems (NOS) that can mange data, users, groups,
security and applications
•Workstation: a personal computer (desktop or laptop) which may or may not be
connected to a network most clients are work station computers
•NIC (network interface card): the device inside a computer that connects a
computer to the network media, thus allowing it to communicate with other
•NOS (network operating system): a software that runs on a server and enables it
to manage data, users, groups, security and applications and other networking
functions (Microsoft windows, LINUX and MAC)
•Host: A computer that enables resource sharing by other computers on the same
•Node: a client, server or other device that can communicate over a network and is
identified by a unique number, known as its network address
•Connectivity device: a specialized device that allows multiple networks or
multiple parts of one network to connect and exchange data.
•Segment: A part of a network composed of a group of nodes that use the same
communications channel for all their traffic.
•Backbone: The part of the network to which segments and significant shared
devices (such as routers switches and servers) connect.
•Topology: The physical layout of a computer network, networks can be arranged
in a ring, bus, or start formation
•Protocol: A standard method or format for communication between networked
•Packet: A distinct unit of data exchanged between nodes on a network. Breaking
a large stream of data into many packets allows a network to deliver that data
•Addressing: The scheme for assigning a unique identifying number to every node
on the network. The type of addressing used depends on the networks protocols
and network operating system. Each network device must have a unique address
so that data can be transmitted reliably to and from that device.
•Transmission media: The means through which data are transmitted and
received. Transition media may be physical such as a wire or cable, or
atmospheric (wireless) such as radio waves.
How networks are used
File and Print services
•Network services: functions provided by a network
•File services: refers to a server’s ability to share data files, applications (word
processing or spreadsheet), and disc storage space.
•File server: A server that provides file services
•Print Services: to share printers across a network also saves time and money.
A central printer, instead of each computer getting its own, a central printer
saves money on maintenance and can handle the printing needs of everyone.
•Allow remote users to connect to the network.
•Remote users: Refers to a person working on a computer on a different
network or in a different geographical location from the Lan’s server.
•Remote access server (access server): allows remote users to log on to the
network, and take advantage of the network just as if they wee logged on to a
work station on the office LAN.
•Convergence: Using the same network to deliver multiple types of
•Unified communications: refers to the centralized management of multiple
network-based communications. Using 1 software program to manage in-
office phone calls, long distance phone calls, cell phones, voice mails, faxes
and text messages.
•Mail services: The oldest network communications services, which
coordinates the storage and transfer of e-mail between users on a network. The
computer responsible for mail services is called a mail server.
•Web server: A computer installed with the appropriate software to supply
web pages to many different clients upon demand.
•Internet Services: include file transfer capabilities, internet addressing
schemes, security filters, and a means for directly logging on to other
computers on the internet.
•Network management services: centrally administer management tasks on the
network, such as ensuring that no more than 20 work stations are using adobe
Photoshop at one time in an organization that purchased a 20-user license for