Welcome All In My Website RizTalk & Yaha se Hamare Networking Course ka 1st Cahpter Shuru Hota hai. Introducing Networking
Chapter 1 - Introducing Networking
Isme ham total 12 topic badi aasani se cover karne wale hai, to shuru karte hai pehle topic se....
1. Computer Network
A computer network is a group of two or more computers interconnected via cables or wireless mode. For sharing hardware and software resources. These resources can be printers, files, CDs, or any software interconnect computers are able to exchange information between each other.
Some example of a computer are:
- Computer in lab are interconnected using a network to share a single printer or software.
- Files shared between computers within a building through a computer network.
- The internet.
2. Network Criteria
i. Performance
It is measured in terms of transit time and response time. Transit time is the time for a message to
travel from one device to another. Response time is the elapsed time between an inquiry and a response.
Performance is dependent on the following factors:
- The number of users
- Type of transmission medium
- Capability of connected network
- Efficiency of software
ii. Reliability
> It is measured in terms of
- Frequency of failure
- Recovery from failures
- Robustness during catastrophe
iii. Security
- It means protecting data from unauthorised access.
3. Benefits of Computer Network File sharing
It provides access to digital media, such as a computer, programs, electronic book or documents. Common methods of storage and transmission include manual sharing utilizing removable media, centralised servers on computer networks.
Application sharing
It enables two or more users to access a shared application or software over the network with the help of the client/server application.
Hardware sharing
In hardware, sharing users can access hardware devices like Printer, Hard disk, Ram, etc. with the help centralised computer or device.
Voice over/IP
Voice over Internet Protocol (IP) is a revolutionary change in telecommunication that allows to send telephone calls (voice data) using standard Internet Protocol (IP) rather than by traditional PSTN.
Time
It reduces the time of sending any information anywhere in the world as it delivered the information faster than any physical transportation.
Distance
We can send any information across the world even you are sitting at a place in the world just you need a network and this enables you to send any information anywhere in the world.
Cost
It is very cheaper than the physical transportation of any information but with the help of the internet, it can be transmitted in a very small amount.
4. Drawback of Computer Network
High Installation Coast
It is expensive to set up deploy a network. Only a trainer person can manage a large network and its maintenance is also costly deal.
Risk of Hacking
A computer network is susceptible to virus attacks and can be hacked Security procedures and robust firewalls need to be setup to prevent such attacks.
Hardware Damages
The hardware and cables used to set up a network are subject to damage and can assault the normal functioning of a network.
5. Network Terminology
Network Nodes
Computer system connected to a network are termed as network nodes
Network Device
A network device is a hardware component that is required for connecting computers in a network. It links the network together to enable communication and controls the data traffic between the network nodes. Bridge, Hub, Switch and Router are some of the examples of such network devices
Network Interface Card
Network Interface Card (NIC) is an electronic circuit card that is required to connect to any computer to a network. It controls data communication between the network nodes and the Internet. It is required for both wired and wireless networks.
MAC Address
The NIC manufacturer assigns MAC addresses into the Local Area Network (LAN) card for wired networks and Wi-Fi card for Wireless networks, Ethernet is an example of a wired network and hence, MAC address is also termed as Ethernet address on an Ethernet LAN
Uniform Resource Locator (URL)
URL is a Web address assigned to a resource. It specifies its location on the network of networks
IP Address
IP address is 32 - bit address assigned to each node or computer in a Transfer Control Protocol / Internet Protocol (TCP / IP) network. IP address helps in identifying a particular node in a network of nodes for data communication
World Wide Web
World Wide Web or WWW is a database of information on the Internet where Web pages are interconnected with hypertext links
Protocol
Protocol is defined as a set of communication rules required for data transmission over the Internet.
Coaxial cable is a type of copper cable specially built with a metal shield and other components engineered to block signal interference. It is primarily used by cable TV companies to connect their satellite antenna facilities to customer homes and businesses. It is also sometimes used by telephone companies to connect central offices to telephone poles near customers. Some homes and offices use coaxial cable, too, but its widespread use as an Ethernet connectivity medium in enterprises and data centres has been supplanted by the deployment of twisted pair cabling.
Twisted-Pair Cable
One of the earliest guided transmission media is twisted pair cables. A twisted pair cable comprises of two separate insulated copper wires, which are twisted together and run in parallel. The copper wires are typically 1 mm in diameter. One of the wires is used to transmit data and the other is the ground reference.
Fibre-optic cable
A fibre optic cable is a network cable that contains strands of glass fibers inside an insulated casing. They're designed for long-distance, high-performance data networking, and telecommunications. Compared to wired cables, fiber optic cables provide higher bandwidth and transmit data over longer distances. Fiber optic cables support much of the world's internet, cable television, and telephone systems.
Radio wave attributes
A radio wave is a type of electromagnetic signal designed to carry information through the air over relatively long distances. Sometimes radio waves are referred to as radio frequency (RF) signals. These signals oscillate at a very high frequency, which allows the waves to travel through the air similar to waves on an ocean. Radio waves have been in use for many years. They provide the means for carrying music to FM radios and video to televisions. In addition, radio waves are the primary means for carrying data over a wireless network.
Infrared communications span only short distances. When networking two infrared devices, they must be within a few feet of each other.
Unlike Wi-Fi and Bluetooth technologies, infrared network signals cannot penetrate walls or other obstructions and work only within a direct line of sight. Anything that blocks that direct line between two IR devices also blocks IR communication.
7.Classification of network Based on size
Types of Computer Network
There are several different types of computer networks. Computer networks can be characterised by their size as well as their purpose.
On the size of a network
The size of a network can be expressed by the geographic area they occupy and the number of computers that are part of the network. Networks can cover anything from a handful of devices within a single room to millions of devices spread across the entire globe.
Some of the different networks based on size are :
- Personal area network, or PAN
- Local area network, or LAN
- Metropolitan area network, or MAN
- Wide area network, or WAN
PAN
PAN (Personal Area Network) is a computer network formed around a person. It generally consists of a computer, mobile, or personal digital assistant. PAN can be used for establishing communication among these personal devices for connecting to a digital network and the internet.
A Local Area Network (LAN) is a group of computer and peripheral devices which are connected in a limited area such as school, laboratory, home, and office building. It is a widely useful network for sharing resources like files, printers, games, and other application. The simplest type of LAN network is to connect computers and a printer in someone’s home or office. In general, LAN will be used as one type of transmission medium. It is a network which consists of less than 5000 interconnected devices across several buildings.
MAN
A Metropolitan Area Network or MAN is consisting of a computer network across an entire city, college campus, or a small region. This type of network is large than a LAN, which is mostly limited to a single building or site. Depending upon the type of configuration, this type of network allows you to cover an area from several miles to tens of miles.
WAN
(Wide Area Network) is another important computer network that which is spread across a large geographical area. WAN network system could be a connection of a LAN which connects with other LAN’s using telephone lines and radio waves. It is mostly limited to an enterprise or an organization.
8.Classification of network Based on Topology
What is Topology ?
Geometric representation of how the computers are connected to each other is known as topology. There are five types of topology – Bus, Star, Ring, Mesh and Hybrid.
BUS
As it uses less cable, it is simple to build and less expensive compared to the other network topologies. Adding new nodes to the network is easier and can be achieved by simply joining additional cables with connectors.
Advantages of bus topology
1. Easy installation, each cable needs to be connected with backbone cable.
2. Less cables required than Mesh and star topology
Disadvantages of bus topology
1. Difficultly in fault detection.
2. Not scalable as there is a limit of how many nodes you can connect with backbone cable.
Star
A star topology is the one in which each peripheral node is connected to a central hub or switch. It is probably the most commonly used network topology for LAN because it is considered the easiest topology to design and implement. The central hub functions as the server for the peripheral nodes or clients. All the network traffic passes through the central hub and this is the only requirement for the topology to be classified as a star topology; the network doesn’t have to resemble a star in the physical arrangement.
Advantages of Star topology
1. Less expensive because each device only need one I/O port and needs to be connected with hub with one link. 2. Easier to install 3. Less amount of cables required because each device needs to be connected with the hub only. 4. Robust, if one link fails, other links will work just fine.
Disadvantages of Star topology
1. If hub goes down everything goes down, none of the devices can work without hub. 2. Hub requires more resources and regular maintenance because it is the central system of star topology.
Ring
As we mentioned earlier, the ring topology is similar to a daisy chain topology but with the loop closed so that the nodes are arranged in a ring or circle. Each node has exactly two peers and the data travels in one direction passing through each intermediate node on the ring until it reaches the destination node. Data can be made to pass in both directions by adding a second connection between the network nodes, creating a dual ring topology.
Advantages of Ring Topology
1. Easy to install.
2. Managing is easier as to add or remove a device from the topology only two links are required to be changed.
Disadvantages of Ring Topology
1. A link failure can fail the entire network as the signal will not travel forward due to failure.
2. Data traffic issues, since all the data is circulating in a ring.
Mesh
A mesh topology is one in which the nodes connect directly and dynamically to many other nodes. It consists of an elaborate structure of point-to-point interconnections among the nodes. You can have a partial mesh topology, where some nodes have two or more connections, or a full mesh topology, where all nodes are fully connected to every other node.
Advantages of Mesh topology
1. No data traffic issues as there is a dedicated link between two devices which means the link is only available for those two devices.
2. Mesh topology is reliable and robust as failure of one link doesn’t affect other links and the communication between other devices on the network.
3. Mesh topology is secure because there is a point to point link thus unauthorized access is not possible.
4. Fault detection is easy.
Disadvantages of Mesh topology
1. Amount of wires required to connected each system is tedious and headache.
2. Since each device needs to be connected with other devices, number of I/O ports required must be huge.
3. Scalability issues because a device cannot be connected with large number of devices with a dedicated point to point link.
Hybrid
A hybrid topology is one in which two or more distinct typologies are combined to build a network in such a way that it doesn’t exhibit any of the standard typologies. Hybrid typologies are commonly found in larger organizations where individual departments can have personalized network typologies based on their needs and network requirements.
Advantages of Hybrid topology
1. We can choose the topology based on the requirement for example, scalability is our concern then we can use star topology instead of bus technology.
2. Scalable as we can further connect other computer networks with the existing networks with different typologies.
Disadvantages of Hybrid topology
1. Fault detection is difficult.
2. Installation is difficult.
3. Design is complex so maintenance is high thus expensive.
9.Transmission mode
These are explained as following below.
1. Simplex Mode
In Simplex mode, the communication is unidirectional, as on a one-way street. Only one of the two devices on a link can transmit, the other can only receive. The simplex mode can use the entire capacity of the channel to send data in one direction.
Example: Keyboard and traditional monitors. The keyboard can only introduce input, the monitor can only give the output.
2. Half-Duplex Mode 
In half-duplex mode, each station can both transmit and receive, but not at the same time. When one device is sending, the other can only receive, and vice versa. The half-duplex mode is used in cases where there is no need for communication in both directions at the same time. The entire capacity of the channel can be utilized for each direction.
3. Full-Duplex Mode
In full-duplex mode, both stations can transmit and receive simultaneously. In full duplex mode, signals going in one direction share the capacity of the link with signals going in another direction, this sharing can occur in two ways: 
Either the link must contain two physically separate transmission paths, one for sending and the other for receiving.
Or the capacity is divided between signals travelling in both directions. 
Full-duplex mode is used when communication in both directions is required all the time. The capacity of the channel, however, must be divided between the two directions.
Example: Telephone Network in which there is communication between two persons by a telephone line, through which both can talk and listen at the same time.
10.Network architecture
A Computer Architecture is a design in which all computers in a computer network are organized. A architecture defines how the computers should get connected to get the maximum advantages of a computer network such as better response time, security, scalability etc. The two most popular computer architectures are P2P (Peer to Peer) and Client-Server architecture.
(1)Peer to Peer Architecture
In peer to peer architecture all the computers in a computer network are connected with every computer in the network. Every computer in the network use the same resources as other computers. There is no central computer that acts as a server rather all computers acts as a server for the data that is stored in them.
12.Consideration for implement a network
Advantages of a Peer to Peer Architecture
1. Less costly as there is no central server that has to take the backup.
2. In case of a computer failure all other computers in the network are not affected and they will continue to work as same as before the failure.
3. Installation of peer to peer architecture is quite easy as each computer manages itself.
Disadvantages of a Peer to Peer Architecture
1. Each computer has to take the backup rather than a central computer and the security measures are to be taken by all the computers separately.
2. Scalability is a issue in a peer to Peer Architecture as connecting each computer to every computer is a headache on a very large network.
(2)Client Server Architecture
In Client Server architecture a central computer acts as a hub and serves all the requests from client computers. All the shared data is stored in the server computer which is shared with the client computer when a request is made by the client computer.
All the communication takes place through the server computer, for example if a client computer wants to share the data with other client computer then it has to send the data to server first and then the server will send the data to other client.
Advantages of Client Server Architecture
1. Data backup is easy and cost effective as there is no need to manage the backup on each computer.
2. Performance is better as the response time is greatly improves because the server is more powerful computer than the other computers in the network.
3. Security is better as unauthorized access are denied by server computer and all the data goes through the server.
4. Scalability is not an issue in this Architecture as large number of computers can be connected with server.
Disadvantages of Client Server Architecture
1. In case of server failure entire network is down.
2. Server maintenance cost is high as the server is the main component in this Architecture
3. Cost is high as the server needs more resources to handle that many client requests and to be able to hold large amount of data.
11. Network Management System
What Does Network Management System (NMS) Mean?
A network management system (NMS) is an application or set of applications that lets network administrators manage a network's independent components inside a bigger network management framework. NMS may be used to monitor both software and hardware components in a network. It usually records data from a network's remote points to carry out central reporting to a system administrator.
The key benefit to NMS is that it permits users to monitor or
manage their entire business operations using a central computer.
Explains Network Management System (NMS)
- A network management system is useful in:
- Network device discovery
- Network device monitoring
- Network performance analysis
- Network device management
- Intelligent notifications, or customizable alerts
12.Consideration for implement a network
Consideration for implement a network
- Change default username and password
- Enable MAC filtering
- Assign static IP address
- Firewall settings
- Port forwarding/mapping
- Disabling ports
- Content filtering/Parent control
- Update Firewall
- Physical security
