Every network follows a set of rules or standards that govern the communication between two or more computers connected to that network. Such a set of rules is known as a protocol. SMTP is a protocol used for transfer of e-mails and other text messages over the internet. FTP is used for transferring files. TELNET is used for operating remote terminal sessions. There are many other protocols like HTTP, TCP/IP, UDP, ICMP.
2. Hierarchy of networks
LAN, MAN and WAN form the hierarchy of networks based on their size and the geographical area they cover.
3. Basic network topologies
There are many ways to classify computer networks. One way is by means of their topology. Some commonly used network topologies include the bus, star and ring.
4. Types of transmission media
Transmission media can broadly be categorized into two classes- guided media and unguided media. In guided media, a signal travels through a physical path like a coaxial cable or optical fiber cable whereas in unguided media, transmission is performed through wireless media by means of radio communication and satellite communication.
They determine the optimum path among many other possible paths available for the completion of transmission.
Repeaters connect different segments of a LAN and forward every frame that they receive. Thus, they act as regenerators.
They segregate a large network into smaller ones. They operate both in physical layer as well as data link layers.
8. Circuit switching
In circuit switching, a dedicated path is established. Data transmission is fast and interactive. There is no call set up delay in circuit switching.
9.Virtual circuit packet switching
In this type of switching, there is no dedicated path. Also, storage facility is required and it involves packet transmission delay.
10. Flow control
Flow control is a mechanism for controlling the flow of data from one device to another over a logical connection. This is extremely important because there should be a synchronization between the sender and the receiver.
11. Error control
Error control includes error detection as well as error correction. It ensures to provide reliable end to end communication by informing the sender of the damaged or lost frames and the sender responds by retransmitting the damaged or lost frames.
The Ethernet is a technology for connecting computers within a building using hardware running from machine to machine. Ethernet uses CSMA/CD in the transmission of packets.
They help in keeping networked computers safe from threats and attacks. Firewalls create barriers to attacks; they get in the way of someone trying to take control over your computer.