What is computer
A computer is an electronic device which receiving information and then perform a sequence of operations according to user input. Or we can say that it’s an electronic machine which makes calculations. Basically if we talking about current timing computer make with two parts. The actual machine with wire, circuits and transistor which we call Hardware. And set of instructions and data which we call Software.
What is network
Basic meaning of network is connected each other, which can access data from one side to another side. It’s a welled arrangement of system in horizontal or vertical views. Or we can say that it’s an inter connected system.
What is Computer Network
Basic mean of computer network is, it’s an inter connect with two or more systems. And their purpose to share their resources. And we talking about now days then that resources mean internet. Other resources may be file server, printer etc.
Need of Computer Network:
- File sharing across the network.
- Internet Sharing.
- Make information exchange easier.
- Sharing of software.
- Sharing Operating-system on remote.
- Multiple users shared single hardware (like printer) at that time.
- Instant messaging.
- Video Conferencing.
- Communication via E-mail.
There are many types of networks but widely used only three type of networks.
- Local Area Network (LAN)
- Metropolitan Area Network (MAN)
- Wide Area Network (WAN)
LOCAL AREA NETWORK (LAN)
LAN is an any communication network for connecting computer systems within a short place like in a building or small group of buildings. Even if two computers are connected from a closed circuit. The first Ethernet had capacity only 2mbps but now a day its 10 to 100 mbps to sharing data.
METROPOLITAN AREA NETWORK (MAN)
MAN is also communicating medium network of computer system but its capacity is larger than LAN. MAN established like in large universities. A recent trend is the installation of wireless MANs.
Mainly used for connecting different branches of an Organization, Office in a city.
WIDE AREA NETWORK(WAN)
WAN is interconnect with broader telecommunication structure from LAN. WAN may be privately owned or rented. It’s like name it is wide area and share anything across in wide area.
Modem is a device which used to converting to signals such as Modem modulates an analog carrier signal, and also demodulates carrier signal to decode the received information.
A router is a device that forwards data packets between computer networks in its own path to destinations system. It is control to routes of packets from source to destination.
A network switch or switching hub is a computer networking device that connects network several segments. It is connecting different types of system or device to the router.
It is defined as applications-specific or process-specific communications endpoint in a computers host operating system.
Ports are divided in two parts:
Physical ports: Computer ports have many uses like connect to printer, monitor, mouse, keyboard, LAN wire with power supply cable. Physical ports are used to connect two hardware or other resources and other part of computer for exchange their information. Such as you want to connect your pen drive then you have to plug-in in only USB port, because its reserved for USB.
Virtual/Internal Ports: Virtual ports are used to connect two application. Virtual or internal ports are part of TCP/IP and through this two application communicate with each other. Management of ports are in under computer and router. Computer and Router decide port number. Basically Virtual ports are virtual path to communicate from computer.
Internal ports are further divided into three ranges:
- Well known ports (0-1023)
- Registered Ports (1024-49151)
- Dynamic Ports (49152-65535)
What is Protocol:
A Protocol is a set of rules that governs the communications between computers on a network. And it makes two or more systems to communicate with each other. Sometimes protocol referred as an access method. One of the most common protocol is HTTP (Hyper Text Transfer Protocol). Other example of ports and protocols:
- 21 – FTP (File Transfer Protocol)
- 22 – SSH (Secured Shell)
- 23 – Telnet
- 25 – SMTP
- 53 – DNS (Domain Name System)
- 80 – HTTP (Hyper Text Transfer Protocol)
- 109 – POP2 (Post Office Protocol v2)
- 110 – POP3 (Post office Protocol v3)
- 443 – HTTPS (Hypertext Transfer Protocol over SSL/TLS)
- 995 – POP3S (Post Office Protocol 3 over TLS/SSL)