Network

This week was one of the best, the information and things we learned were important and helped get better and obvious information, I would share here important information about networking.
What is computer networking?
It is a simple group of interconnected computers that can connect two or more computers via hardware or software, and able to communicate with each other. the example of computer network are internet, school network, e-banking etc. computer network has three advantages by using it such as
(1) resource sharing (hardware , software)
(2) information sharing (easy accessibility from anywhere, search capability)
(3) promote communication and collaboration (Email, message broadcast)
What is the network components?
It is major components are

• communication media
• interconnecting devices
• computers
• networking software
• applications

Basic networking concepts
There are

1. topology (the physical layout of the network)
2. protocol (the rules in data communication)
3. architecture (hardware and software are integrated to form a working)

Data communication
computer network are communicating between data and computer. it exist at least three element to communicate such as sender, medium and receiver.

Data transmission characteristics
there are bandwidth(rate of transmission), analog or digital(type of signal) and serial or parallel(order of bits).
In Bandwidth that can transmitted measured by bits/sec and the range that medium can transmit data. And then, the signal changes is known as Baud rate.
 Analog and Digital signal transmission
Analog signal transmit along conventional telephone lines, that's also called radio signal.
Digital signal carries discrete between data and computer devices and it represent a pattern of bits.

Serial and Parallel transmission
Serial transmission are transmitted one bit at a time over a medium.
Parallel transmission are transmitted several bits together in one go over a medium.

Types of Network
There are three types of network ; LAN, MAN, and WAN. LAN stand for Local Area Network. It is a network of computer that are in the same physical location, or that spans a small area such as a building or an office. Two types of LAN are Intranet and Extranet. MAN stand for Metropolitan Area Network. It is a network of computer that usually spans a city or a large campus. A MAN usually interconnects a number of LANs. WAN stand for Wide Area Network. It is a network that spans a wide geographical area. The example of WAN are Ethernet and Aparnet.


Types of Topology:

1) In networking terms, the structure you are planning to connect the computers to, is called network topology.

2) Network topology is also referred to as the configuration of a network.

3) It usually refers to the physical arrangement of the computers and other networking devices that are linked together.

4) According to the needs, there are three main types of network topology.

They are bus topology, star topology and ring topology.

Bus Topology

1) In communications technology, you think of a bus as a common “highway” on which data is transmitted.

2) A bus refers to the main physical pathway or central cable where all other devices are connected to it. Like a major motor highway, all traffic flow will be affected if this main “road” is broken.

Ring Topology

1) A ring topology consists of all computers and other devices that are connected in a loop.

2) Ring topology is also known as a ring network. A ring network can be found in Local Area Networks. In a ring network each node directly connect to two neighboring nodes.

3) A server may exist in a ring network, but it will not connect to all the nodes in the network.

Star Topology

1) In the early days of computer networking, all computers were connected to a centralized mainframe computer.

2) All resources and management of information were centered in this main computer.

The idea of a centralized mainframe computer is where the basic concept of a star topology comes from.

3) A star topology consists of a central host which acts as the center, and all nodes connect to the host. A star topology is also known as star network.



The data can be transmitted or transferred from one computer to another and send the data  through the channel use by transmission media which may be either by physical or wireless.

Physical Media
There are

1. Twisted-pair cable that consists of two independently insulated wires twisted around each other.
2. Coaxial cable that consist of an insulated center wire grounded by a shield of braided wire.
3. Fiber-optic cable that contains hundreds of clear fiberglass of plastic fibers.
4. ISDN line, it is a special digital telephone that transmits and receives information at very high speed.

Twisted-pair cable

Fiber optic cable

ISDN line

Coaxial cable

Wireless Media

Microwave system that transmits data via high-frequency radio signals through the atmosphere.

Satellite system that receive transmitted signals, amplify and transmit the signals to the appropriate locations.

Cellular technology that uses antennae resembling telephone towers to pick up radio signals within a specific area.

Infrared technology that transmits data as infrared light waves from one device to another, providing wireless links between PCs and Peripherals.

There are three type of network such as

1.  LAN (local Area Network), this network used for same physical location or a small area such as building of an office. It has two type of LAN. That is

    a.    Intranet

    b.      Extranet

2.    MAN (Metropolitan Area Network), this is used in a city.

3.    WAN (Wide Area Network), it spans a wide geographical area. There are several types of WANS, that is

(a) Metropolitan Area Network(MAN)

(b) Public Access Network(PAN)

(c) Value Added  Network(VAN)

(d) Virtual Private Network(VPN)

Peer-to-peer network

In that network, the entire computers are considered equal and each controls its own information. These networks are not expensive and easy to install. It can use in home networks and in small companies. It has both advantages and disadvantages by using peer-to-peer network.

The advantages are easy to install and configure, no dedicated server, inexpensive to purchase and operate no additional equipment or software and no dedicated administrators.

The advantages are security applies and single resource at a time, users may have many difference passwords, machine sharing resources may suffers reduced performance and does not usually work well with more than 10 users and so on.

Server based network

     it is offer to centralize control and is designed for secure operations. sever responds to client request and may be dedicated, handling only requests from client communities. and then the server require faster CPUs, more memory, lager disk drives and extra peripherals. it also has advantages and disadvantages. simplifies network administration, more powerful equipment, single password for network log on, these are advantages. For disadvantages are server failure renders network unusable, more expensive, server failure causes loss of network resources and so on.

Client/Server Network

Network services are located in a dedicated computer whose only function is respond to the requests of clients. the sever contains the file, print, application, security and other services in a central computer that is available to respond to client requests.

Client Server network