Computer Network
Network Topology
Network topology is the arrangement of the elements of a communication network. Network topology can be used to define or describes the arrangements of various types of telecommunication networks, including command and control radio networks, industrial field because and computer networks.
Different Types of Topologies
a. Mesh Topology
A mesh topology is a type of computer network in which each node(computer or other device) is connected to every other node in the network. This type of network is often used in large organizations or companies it can be handle a large amount of data traffic and can be easily expanded.
b. Star Topology
A star topology is a topology for a Local Area Network(LAN) in which all nodes are individually connected to a central connection point, like a hub or a switch. A star takes a more cable than e.g. a bus, but the benefit is that if a cable fails, only one node will be brought down.
c. Bus Topology
Bus topology is a type of network topology in which all device are connected to a single cable called a 'bus'. This cable serves as a shared communication medium, allowing all devices on the network to receive the same signal simultaneously.
d. Ring Topology
Ring topology is a type of network configuration where devices are connected in a circular manner, forming a closed loop. In this setup, each device is connected to exactly two other devices, creating a continuous pathway for data transmission.
e. Hybrid Topology
Hybrid Topology is a type of network topology in which two or more different topologies are integrated or combined to lay out a network. In layman's terms, hybrid topology is the combination of two or more networks. The network type could be Star, Ring, Bus or Mesh.
Open System Interconnection(OSI) Reference Model
The Open System Interconnection model is a conceptual model from the International Organization for Standardization that "provides a common basis for the coordination of standards development for the purpose of systems interconnection.
Various Types of OSI Layers
a. Application Layer
The application layer is used by end-user software such as web browsers and email clients. It provides protocols that allow software to send and receive information and present meaningful data to users. Example: HTTP, FTP, POP, SMTP and DNS etc.
b. Presentation Layer
The presentation layer prepares data for the application layer. It defines how two devices should encode, encrypt, and compress data so it is received correctly on the other end.
c. Session Layer
The session layer creates communication channels, called sessions, between devices. It is responsible for opening sessions, ensuring they remain open and functional while data is being transferred, and closing them when communication ends.
d. Transport Layer
The transport layer takes data transferred in the session layer and breaks it into "segments" on the transmitting end. It is responsible for reassembling the segments on the receiving end, turning it back into data that can be used by the session layer.
e. Network Layer
The network layer has two main functions. One is breaking up segments into network packets, and reassembling the packets on the receiving end. The other is routing packets by discovering the best path across a physical network.
f. Data Link Layer
The data link layer establishes and terminates a connection between two physically-connected nodes on a network. It breaks up packets into frames and sends from source to destination. This layer is composed of two parts- Logical Link Control(LLC), Media Access Control(MAC)
g. Physical Layer
The physical layer is responsible for the physical cable or wireless connection between network nodes. It defines the connector, the electrical cable or wireless technology connecting the devices, and is responsible for transmission of the raw data, which is simply a series of 0s and 1s, while taking care of bit rate control.
Comparison Between TCP/IP and OSI Model
a. Both are logical models.
b. Both define standards for networking.
c. Both provide a framework for creating and implementing networking standards and devices.
d. Both divide the network communication process into layers.
e. In both models, a single layer defines a particular functionality and sets standards for that functionality only.
f. Both models simplify the troubleshooting process by dividing complex functions into similar components.
IP Address
An Internet Protocol Address(IP Address) is a numerical label such as 192.0.2.1 that is connected to a computer network that uses the Inernet Protocol for communication. An IP address servers two main functions: network interface identification and location addressing.
Subnet Mask
A subnet mask is defined as a 32-bit address that segregates an IP address into network bits that identify the network and host bits that identify the host device operating on that network.
Difference Between Static and Dynamic IP Address
| Static IP Address | Dynamic IP Address |
|---|---|
| It is provided by ISP(Internet Service Provider). | While it is provided by DHCP(Dynamic Host Configuration Protocol). |
| Static ip address is difficult to designate. | While dynamic ip address is easy to designate. |
| Static ip address is more stable than dynamic ip address. | While dynamic ip address is less stable than static ip address. |
| The cost to maintain the static ip address is higher than dynamic ip address. | While the maintaining cost of dynamic ip address is less than static ip address. |
| It is used where computational data is less confidential. | While it is used where data is more confidential and needs more security. |
E-mail
E-mail(Electronic Mail): is a messages transmitted and received by digital computers through a network. An E-mail system allows computer users on a network to send text, graphics, sounds, and animated images to other users.
Email has existed in some form since the 1970s, when programmer Ray Tomlinson created a way to transmit messages between computer systems on the Advanced Research Projects Agency Network(ARPANET). Modern forms of email became available for widespread public use with the development of email client software(e.g. Outlook) and web browsers, the latter of which enables users to send and receive message over the Internet using web-based email clients(e.g. Gmail).
Internet
The Internet is a vast network that connects computers all over the world. Through the Internet, people can share information and communicate from anywhere with an Internet connection.
Advantages of Internet
Entertainment: The internet provides people to access endless entertainment. With the internet, you can watch movies, videos, play games online, listen to music etc. There are many sites available on the internet which contain different entertainment material like music, videos, and more.
Social Network: Social networking is the sharing of data with people across the planet. Aside from being an entertainment website, it's many uses. The internet has given a massive gain in these social networking sites as it connects people who are far away in just a few seconds.
Learning: The web has now become a neighborhood of education. Education like homeschooling is definitely administered using the web. Teachers can upload their teaching videos on the web and nowadays many more platforms have come to teach students because of the accessibility of the internet.
Internet Banking: Internet Banking is one of the main advantages of the internet as it helps people nowadays in using banks in a digital way which helps in people not going to banks, not standing in queues in banks, etc. People can use banking services at their fingertips with the help of the internet.
Cloud Computing: One of the biggest advantages of the Internet offers connectivity to your computer and Internet enabled devices to connect with cloud services, such as cloud storage and cloud computing. A device can have access to more powerful computers to perform complex tasks with cloud computing whereas your business work on other tasks.
Internetwork
An internetwork is defined as two or more computer network LANs or WAN or computer network segments are connected using devices, and they are configured by a local addressing scheme. This process is known as internetworking.
Types of Internetwork
The types of internetwork are:
a. Extranet: An extranet is a communication network based on the internet protocol such as Transmission Control Protocol and Internet Protocol. It is used for information sharing. The access to the extranet is restricted to only those users who have login credentials. It can be categorized as MAN, WAN or other computer networks. An extranet cannot have a single LAN, at least it must have one connection to the external network.
b. Intranet: An intranet is a private network based on the internet protocol such as Transmission Control Protocol and Internet Protocol. An Intranet belongs to an organization which is only accessible by the organization's employee or members. The main aim of the intranet is to share the information and resources among the organization employees.
WWW
The World Wide Web(WWW), commonly known as the Web, is an information system where documents and other web resources are identified by Uniform Resource Locators, which may be interlinked by hypertext, and are accessible over the Internet. World Wide Web was invented in 1989 by Tim Berners Lee.
