NETWORK
A network is a collection of computers and devices
connected together via communications devices and
transmission media. Many businesses network their
computers together to facilitate communications, share
hardware, share data and information, share software
and transfer funds.
An excellent example of a network is the Internet, which
connects millions of people all over the world.
BASIC PROCESSING SYTRATEGIES
When an organization needs to use two or more
computer systems, one of three basic processing strategies can be followed and they are:
● Centralized processing. All processing occurs in a single location or facility. This
approach offers the highest degree of control because all data processing is done on a
single centrally managed computer.
● Decentralized processing. Processing devices are placed at various remote
locations. The individual computer systems are isolated and do not communicate with
each other.
● Distributed processing. Computers are placed at remote locations but connected
to each other via a network. One benefit of distributed processing is that processing
activity can be allocated to the location (s) where it can most efficiently occur.
TYPES OF COMPUTER NETWORKS
● Local Area Network (LAN) refers to computers that are relatively near each other and
connected by wires or wireless links. It maybe composed of 10 interconnected
computers or 100 interconnected computers, which are located in different floors of a
building or adjacent buildings. A wireless LAN (WLAN) is a LAN that uses no physical
wires.
● Wide Area Network (WAN) is typically composed of several LANs, which are distributed
over a wider geographic area such as city, country or even continent.
● Metropolitan Area Network (MAN) is a data network designed for a town or city. In terms
of geographic breadth, MANs are larger than local-area networks (LANs), but smaller
than wide-area networks (WANs). MANs are usually characterized by very high speed
connections using fiber optical cable or other digital media.
NETWORK ARCHITECTURE
It refers to the design of computers, devices, and media in a network. It is categorized as
client/server and peer-to-peer.
NETWORK
● Client/Server. one or more computer act as a server and the other computers on the
network request services from the server. A server controls access to the hardware,
software, and other resources on the network and provides a centralized storage area
for programs, data, and information. The clients are other computers and mobile devices
on the network that rely on the server for its resources.
● Peer-to-Peer. Each computer called a peer, has equal responsibilities and capabilities,
sharing hardware, data, or information with other computers with other computers on
the peer-to-peer network.
○ Internet Peer-to-Peer is described as an Internet network on which users access
each other's hard disks and exchanges files directly over the Internet.
NETWORK TOPOLOGY
A network topology refers to the physical connection of wires that connect the nodes of
the network. Nodes refer to the individual computers within a network.
● In a linear bus topology, the server (s), nodes and other hardware devices are connected
to a single conduit or main line. the nodes of the bus network transmit data and hope
that the data will not collide with the data transmitted by the other nodes. If collision
occurs, each node waits for a small, random amount of time before attempting to re-
transmit.
● In a star topology, the server (s), nodes and other hardware devices are connected to a
central hub. All messages and data from the source node must first pass through the
central hub before it can reach the target node. The hub is responsible for preventing
data collision. A broken down node will not cause the network to breakdown. However, if
the hub is broken, the whole network is also lost.
● In a ring topology, the server (s), nodes, and other hardware devices are connected in a
circular chain where each node is connected to the next. The last node to be connected
is connected to the first node, which forms a ring. With this topology, send messages
will pass through connecting nodes until it reaches the target node.
● Mesh topology. In a full mesh network, each network node is connected to every other
node in the network. Due to this arrangement of nodes, it becomes possible for a
simultaneous transmission of signals from one node to several other nodes. In a
partially connected mesh network, only some of the network nodes are connected to
more than one node. This is beneficial over a fully connected mesh in terms of
redundancy caused by the point-to-point links between all the nodes. The nodes of a
mesh network require possessing some kind of routing logic so that the signals and the
data traveling over the network take the shortest path during each of the transmissions.
● Tree topology is also known as a hierarchical topology and has a central root node that
is connected to one or more nodes of a lower hierarchy. In a symmetrical hierarchy, each
node in the network has a specific fixed number of nodes connected to those at a lower
level.
● In this topology, the other types of topologies are combined to form a combination or
hybrid network topology. Hybrid topologies are usually used to connect different floors
or rooms or a building.
