Definition of a
Network
When you have two or more computers connected to each other, you have a
network. The purpose of a network is to enable the sharing of files and
information between multiple systems. The Internet could be described as a
global network of networks. Computer networks can be connected through cables,
such as Ethernet cables or phone lines, or wirelessly, using wireless
networking cards that send and receive data through the air.
Advantages &
Disadvantages of Networking
·
Advantages of Computer Networking
1. Easy Communication and Speed
It is very easy to communicate through a
network. People can communicate efficiently using a network with a group of
people. They can enjoy the benefit of emails, instant messaging, telephony,
video conferencing, chat rooms, etc.
2. Ability to Share Files, Data and Information
This is one of the major advantages of
networking computers. People can find and share information and data because of
networking. This is beneficial for large organizations to maintain their data
in an organized manner and facilitate access for desired people.
3. Sharing Hardware
Another important advantage of networking is
the ability to share hardware. For an example, a printer can be shared among
the users in a network so that there’s no need to have individual printers for
each and every computer in the company. This will significantly reduce the cost
of purchasing hardware.
4. Sharing Software
Users can share software within the network
easily. Networkable versions of software are available at considerable savings
compared to individually licensed version of the same software. Therefore large
companies can reduce the cost of buying software by networking their computers.
5. Security
Sensitive files and programs on a network can
be password protected. Then those files can only be accessed by the authorized
users. This is another important advantage of networking when there are
concerns about security issues. Also each and every user has their own set of
privileges to prevent them accessing restricted files and programs.
6. Speed
Sharing and transferring files within networks
is very rapid, depending on the type of network. This will save time while
maintaining the integrity of files.
·
Disadvantages of Networking
1. Breakdowns and Possible Loss of Resources
One major disadvantage of networking is the
breakdown of the whole network due to an issue of the server. Such breakdowns
are frequent in networks causing losses of thousands of dollars each year.
Therefore once established it is vital to maintain it properly to prevent such
disastrous breakdowns. The worst scenario is such breakdowns may lead to loss
of important data of the server.
2. Expensive to Build
Building a network is a serious business in
many occasions, especially for large scale organizations. Cables and other
hardware are very pricey to buy and replace.
3. Security Threats
Security threats are always problems with large
networks. There are hackers who are trying to steal valuable data of large
companies for their own benefit. So it is necessary to take utmost care to
facilitate the required security measures.
4. Bandwidth Issues
In a network there are users who consume a lot
more bandwidth than others. Because of this some other people may experience
difficulties.
Although there are disadvantages to networking,
it is a vital need in today’s environment. People need to access the Internet,
communicate and share information and they can’t live without that. Therefore
engineers need to find alternatives and improved technologies to overcome
issues associated with networking. Therefore we can say that computer
networking is always beneficial to have even if there are some drawbacks.
Network Classifications – LAN, MAN, and WAN
LAN
A local area network is a computer network that interconnects computers
within a limited area such as a home, school, computer laboratory, or office
building, using network media.
MAN
A metropolitan area network is a computer network in which two or more computers
or communicating devices or networks which are geographically separated but in
same metropolitan city and are connected to each other are said to be connected
on MAN.
WAN
A wide area network (WAN) is a network that covers a broad area (i.e.,
any telecommunications network that links across metropolitan, regional,
national or international boundaries) using leased
telecommunication lines. Business
and government entities utilize WANs to relay data among employees, clients,
buyers, and suppliers from various geographical locations.
Network Topologies
What is a network topology? In communication networks, a topology is a usually
schematic description of the arrangement of a network, including its nodes and
connecting lines. There are two ways of defining network geometry: the physical
topology and the logical (or signal) topology.
Bus Topology
In the bus network topology, every workstation is connected to a main
cable called the bus. Therefore, in effect, each workstation is
directly connected to every other workstation in the network.
Star Topology
In the star network topology, there is a
central computer or server to which all the workstations are directly
connected. Every workstation is indirectly connected to every other through the
central computer.
Ring Topology
In the ring network topology, the workstations
are connected in a closed loop configuration. Adjacent pairs of workstations
are directly connected. Other pairs of workstations are indirectly connected,
the data passing through one or more intermediate nodes.
Mesh Topology
The mesh network topology employs either of
two schemes, called full mesh and partial mesh. In the full mesh topology, each
workstation is connected directly to each of the others. In the partial mesh
topology, some workstations are connected to all the others, and some are
connected only to those other nodes with which they exchange the most data.
Wireless Topology
In any network setup, network topology
plays an important role without which
network cannot be established whatsoever. In other words, whenever two or more
machines are connected to each other, a topology is automatically formed.
Unlike wired networks that have multiple topologies, wireless networks have only two
topologies namely Infrastructure and Ad Hoc.
Since wireless networks work on unguided media, it makes sense to have limited
number of topologies while configuring the wireless network setups. Moreover,
since wireless networks are a bit complicated configure as compared to the
wired networks, it is essential for the administrators to have complete and in-depth
knowledge of wireless networking before they finally start establishing
wireless networks in production environments.
Hybrid Topology
Before starting about Hybrid topology, we saw that a network
topology is a connection of various links and
nodes, communicating with each other for transfer of data.
Now let’s discuss what Hybrid Network topology is and why it finds its
application in Wide Area Networks. Hybrid, as the name suggests, is mixture of
two different things. Similarly in this type of topology we integrate two or
more different topologies to form a resultant topology which has good points (as
well as weaknesses) of all the constituent basic topologies rather than having
characteristics of one specific topology. This combination of topologies is
done according to the requirements of the organization.
For example, if there exist a ring topology in one office department while a
bus topology in another department, connecting these two will result in Hybrid
topology. Remember connecting two similar topologies cannot be termed as Hybrid
topology. Star-Ring and Star-Bus networks are most common examples of hybrid
network.
Basic Administration Network Models
Client/Server Network
An architecture in which the user's PC (the client) is the requesting
machine and the server is the supplying machine, both of which are connected
via a local area network (LAN) or a wide area network (WAN) such as the
Internet. Throughout the late 1980s and early 1990s, client/server was the hot
buzzword as applications were migrated from minicomputers and mainframes with
input/output terminals to networks of desktop computers.
With ubiquitous access to company LANs and the Internet, almost everyone works
in a client/server environment today. However, to be true client/server, both
client and server must share in the business processing. To understand this
principle, follow the examples below of a query to a hypothetical database of a
million records, each 1,000 bytes long. Notice the amount of data flowing over
the network.
Network operating systems can be based on a client/server architecture in which a server enables multiple clients to share
resources.[1] Client/server network operating systems
allow the network to centralize functions and applications in one or more
dedicated file servers. The server is the center of the system, allowing access
to resources and instituting security. The network operating system provides
the mechanism to integrate all the components on a network to allow multiple
users to simultaneously share the same resources regardless of physical
location.[3][4]
·
Examples:
Advantages
·
Centralized servers are more stable.
·
Security is provided through the server.
·
New technology and hardware can be easily
integrated into the system.
·
Servers are able to be accessed remotely from
different locations and types of systems.
Disadvantages
·
Cost of buying and running a server are high.
·
Dependence on a central location for operation.
·
Requires regular maintenance and updates.
Peer-to-Peer Network
A peer-to-peer
(P2P) network is a type of decentralized and distributed network architecture in which individual nodes in the network (called"peers") act as both
suppliers and consumers of resources, in contrast to centralized client–server model where client nodes request access to resources
provided by central servers.
Networks in
which all computers have equal status are called peer-to-peer or P2P networks.
In a
peer-to-peer network, tasks (such as searching for files or streaming
audio/video) are shared amongst multiple interconnected peers who each make a
portion of their resources (such as processing power, disk storage or network bandwidth) directly available to other network participants, without
the need for centralized coordination by servers.[1]
In a peer-to-peer network operating system users are
allowed to share resources and files located on their computers and access
shared resources from others. This system is not based with having a file
server or centralized management source. A peer-to-peer network sets all
connected computers equal; they all share the same abilities to use resources
available on the network.[3]
·
Examples:
·
AppleShare used for networking connecting Apple
products.
Network Operating Systems (NOS)
·
Cisco
IOS (formerly "Cisco Internetwork
Operating System").
·
VRP (Versatile Routing Platform), used in
routers from Huawei.
