COMPUTER NETWORKING FOR CCNA BEGINERESS

INTRODUCTION

WHAT IS A COMPUTER NETWORK?

A computer network is a group of interconnected computers and other devices that communicate with each other to share resources and information. These devices can be connected through wired or wireless connections and can range from personal computers to servers, routers, switches, printers, and other network devices.

Computer networks allow individuals and organizations to share data and resources, including files, printers, and internet connectivity. They can be used for a variety of purposes, such as accessing remote resources, communicating with others, sharing data and information, and collaborating on projects.

TYPES OF COMPUTER NETWORK

• LAN:- Local Area Network

• WAN:- Wide Area Network

• MAN:- Metropolitan Area Network

• PAN:- Personal Area Network

Each type of network has its own unique characteristics, advantages, and limitations, and can be configured and managed in different ways to meet specific requirements.

DIFFERENCE B/W NETWOR AND NETWORKING?

A network refers to a group of interconnected devices and systems, such as computers, servers, switches, routers, and other network devices that can communicate with each other to share resources and information.

Networking, on the other hand, is the process of designing, implementing, and managing networks. Networking involves setting up and configuring network devices, connecting them together, and establishing communication protocols and standards to ensure that the devices can communicate effectively. Networking also involves managing the security, performance, and reliability of the network.

In essence, a network is a physical or virtual infrastructure of interconnected devices, while networking is the process of establishing and maintaining that infrastructure to ensure efficient and effective communication between devices.

( As you can see they are co-related with each other )

DIFFRENCE B/W NETWORK AND THE INTERNET?

A network refers to a collection of computers, servers, and other devices that are connected together to share resources such as files, printers, and internet connectivity. Networks can be small, such as a home network, or they can be very large, such as a corporate network spanning multiple locations.

The Internet, on the other hand, is a global network of interconnected networks that use the standard Internet Protocol (IP) to communicate with each other. The internet allows people all over the world to communicate with each other, share information, and access online services such as email, social media, and e-commerce.

In other words, a network is a localized system that connects devices within a specific geographic area, while the internet is a global system that connects networks all around the world.

WHAT IS THE INTERNET?

The term "internet" refers to a system of linked, globally distributed computer networks that communicate with one another via the IP protocol. It's a vast network of networks that enables people all over the world to communicate with each other, share information, and access a wide range of online services.

The Internet was originally developed in the 1960s as a way for government researchers to communicate with each other. Over time, it grew into a global network that connected universities, corporations, and eventually individuals around the world.

Today, the internet has become an essential part of modern life, connecting billions of people to each other and to a wealth of information and services. With the internet, people can communicate instantly with anyone in the world, access vast amounts of information on any topic, and conduct business and commerce from virtually anywhere

WHAT IS NETWORK (BRIEF)

A network refers to a group or system of interconnected entities, such as computers, devices, or people, that can communicate and share information with each other. In the context of technology, a network typically refers to a collection of devices or computers that are connected together to enable communication and the sharing of resources, such as files, printers, or internet access.

There are many different types of networks, including local area networks (LANs) that connect devices in a specific geographic area, wide area networks (WANs) that connect devices over a larger geographic area, and wireless networks that allow devices to connect without the need for physical cables. Networks can also be classified based on their topology, which describes the physical or logical arrangement of devices and connections within the network.

• NETWORK PACKET

Protocols based on packet-mode transmission are used by the majority of current computer networks. A structured data unit known as a network packet is transported via a packet-switched network.

Control information and user data (payload) are the two forms of data that make up packets. Control information gives the network the data it needs to send user data to users, such as source and destination network addresses, error-detection codes, and sequencing details. Control data is often contained in packet headers and trailers, with payload data sandwiched in between.

Compared to a circuit-switched network, users can more effectively share the bandwidth of the transmission medium when using packets. If more than one user doesn't utilize the link at once, it can be filled with packets from other users when one user isn't sending any, allowing the cost to be shared and interference to be minimal. The path that a packet must take through a network is frequently not immediately available. The packet is then queued and waits for a free link in such a scenario.

The maximum transmission unit (MTU) of packet networks' physical link technologies often sets a restriction on the size of packets. A lengthy message might be divided into smaller packets before being transported, then after the packets arrive, they are put back together to form the original message.

• Network Topology

Network topology refers to the physical or logical arrangement of devices and connections within a network. There are several common types of network topology:

a. Bus Topology

b. Star Topology

c. Ring Topology

d. Mesh Topology

e. Hybrid Topology

The choice of network topology depends on factors such as the size of the network, the number of devices that need to be connected, the type of data being transmitted, and the level of redundancy and fault tolerance required.

a)BUS TOPOLOGY

Bus topology is a type of network topology in which all devices in the network are connected to a single communication cable, called a bus. Data is transmitted along the bus to all devices connected to it.

In a bus topology, each device is connected to the bus through a T-connector, which splits the signal into two parts, allowing it to flow in both directions. This arrangement provides a simple and inexpensive way to connect multiple devices in a network, as only one cable is required.

One of the advantages of bus topology is that it is easy to add new devices to the network, as they can be connected to the bus by simply plugging them into the T-connector. However, the disadvantage is that a fault in the cable or a problem with one of the T-connectors can cause the entire network to go down.

Additionally, because data is transmitted to all devices on the network, bus topology can suffer from data collisions and congestion, which can degrade network performance. For this reason, bus topology is generally used for small networks with low traffic volume.

b)STAR TOPOLOGY

All of the devices in the network are linked to a single hub or switch in a network structure known as a star topology. The hub acts as a central point of communication, receiving data from each connected device and forwarding it to the intended recipient.

In a star topology, each device is connected to the hub using a separate cable or link. This arrangement allows for easy identification and isolation of faults or problems in individual devices or cables, making it easier to troubleshoot and repair the network.

Data transmission in a star topology is typically faster and more reliable than in a bus topology, as each device has its own dedicated link to the hub, which minimizes the risk of data collisions and congestion.

However, star topology can be more expensive to set up than other topologies, as it requires additional cabling and hardware for each device to connect to the hub. Additionally, the hub itself can become a single point of failure, as a malfunctioning hub can cause the entire network to go down.

c)RING TOPOLOGY

Ring topology is a type of network topology in which all devices in the network are connected in a closed loop, with each device connected to its neighboring devices. Data is transmitted around the loop in one direction, with each device receiving the data and forwarding it to the next device until it reaches its intended recipient.

In a ring topology, there is no central hub or switch, and each device acts as a repeater, amplifying and forwarding the data signal to the next device. This arrangement provides a more balanced load on the network than a bus topology, as each device contributes to the transmission of data around the loop.

Ring topology can be more fault-tolerant than other topologies, as a break in the loop at any point will only affect the devices on either side of the break, and The network as a whole can continue operating. However, if too many devices are added to the network or if the loop is too long, signal degradation can occur, leading to reduced network performance.

Additionally, because data transmission in a ring topology is dependent on the successful transmission of data through each device in the loop, the failure of a single device can cause the entire network to go down.

d)MESH TOPOLOGY

Mesh topology is a type of network topology in which every device in the network is connected to every other device in the network, forming a fully connected network. In a mesh topology, data can be transmitted through multiple paths, which creates redundancy and fault tolerance in the network.

Both complete mesh and partial mesh topologies exist. In a full mesh topology, every device is connected to every other device, while in a partial mesh topology, some devices are connected to all other devices, while others are only connected to some devices.

Mesh topology provides the highest level of redundancy and fault tolerance of any network topology, as multiple paths are available for data transmission, ensuring that the network can continue to function even if one or more devices or links fail. Additionally, mesh topology can provide high bandwidth and low latency, as there are multiple paths available for data transmission, which reduces congestion and improves network performance.

However, mesh topology can be expensive and complex to implement, as it requires a large number of cables and ports, and configuration and management can be challenging.

e)HYBRID TOPOLOGY

An example of a hybrid topology is a star-bus or ring-mesh topology, which mixes two or more different network topologies. A hybrid topology can provide the benefits of multiple topologies while minimizing their limitations.

For example, a hybrid topology combining a star and bus topology can create a network with the centralized management and fault tolerance of a star topology, while also allowing for the expansion and scalability of a bus topology. Similarly, a hybrid topology combining a ring and mesh topology can create a network with the redundancy and fault tolerance of a mesh topology, while also providing the simplicity and ease of configuration of a ring topology.

A hybrid topology can be tailored to meet the specific needs of a network, based on factors such as the size of the network, the types of devices being used, the amount of traffic on the network, and the level of redundancy and fault tolerance required.

However, hybrid topologies can be more complex to design and manage than single-topology networks, and the use of multiple topologies can increase the cost of hardware and maintenance.

• OVERLAY NETWORK

A sort of computer network known as an overlay network is constructed on top of an existing network, typically the Internet. A virtual network that is independent of the physical network architecture can be formed by running software on top of the underlying network infrastructure to create an overlay network.

In an overlay network, virtual links or tunnels—created by the software running on top of the underlying network—are used to connect nodes (devices) to one another. These connections can be made between nodes regardless of where they are physical, enabling the construction of a dispersed network that can cross geographical boundaries.

Applications like peer-to-peer file sharing, virtual private networks (VPNs), and content distribution frequently use overlay networks. To distribute the material to end users from many places and decrease latency and increase performance, a content delivery network (CDN) can, for instance, use an overlay network.

Data transferred through overlay networks is often encrypted and can be routed across numerous nodes, making it harder to intercept or eavesdrop on communications. As a result, overlay networks can also boost security and privacy.

• NETWORK LINKS

In computer networking, a network link is a communication channel that allows data to be transmitted between devices in a network. Network links can be physical or logical, and are typically classified by their data transfer rate, distance, and transmission medium.

Physical network links refer to the actual physical connections between devices in a network, such as copper or fiber-optic cables, wireless links, or satellite links. These links are typically categorized by their data transfer rate, which can range from kilobits per second (kbps) to gigabits per second (Gbps), and their maximum distance, can be anywhere between a few meters and thousands of km.

Logical network links, on the other hand, refer to the virtual connections that are created between devices in a network using networking protocols such as TCP/IP or OSI. Logical links allow data to be transmitted between devices that are not physically connected, such as devices on different networks or connected to different routers.

The performance and reliability of a network link can have a significant impact on the overall performance and reliability of a network. Factors that can affect network links include signal degradation, interference, distance, and the quality of the cabling or equipment used to create the link. As a result, network administrators need to carefully monitor and manage network links to ensure that they are operating correctly and efficiently.

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