Essential Foundations for Learning Computer Network: A Beginner’s Guide

What is Computer Network?

A computer network is a collection of interconnected computers, servers, devices, and other hardware components that are linked together to enable communication, resource sharing, and data exchange between them. These devices can be connected using wired or wireless connections and can be located in the same room or spread out over vast geographical areas.

Computer networks are used to facilitate communication and data exchange between devices and users, allowing them to share resources, data, and services. Networks can be used for a variety of purposes, such as accessing the internet, sharing files and printers, sending and receiving emails, and connecting to other devices and networks.

The internet is the largest and most widely used computer network in the world, connecting billions of devices across the globe. Other types of computer networks include local area networks (LANs), wide area networks (WANs), metropolitan area networks (MANs), and personal area networks (PANs).

Types of computer networks

LAN, WAN, MAN, and PAN are four different types of computer networks, each with unique characteristics and applications. Here are brief descriptions and examples of each:

Local Area Network (LAN): A LAN is a network that connects computers and devices within a limited geographical area, such as an office, building, or campus. A LAN is typically owned and operated by a single organization and is used for sharing resources such as printers, files, and internet connectivity.

Example: A LAN may connect all of the computers within a small business or school.

Wide Area Network (WAN): A WAN is a network that spans a large geographical area, such as a country or even the entire world. WANs connect LANs and other networks together, enabling communication and data exchange across long distances.

Example: The internet is the largest and most well-known WAN, connecting billions of devices across the globe.

Metropolitan Area Network (MAN): A MAN is a network that spans a large geographical area, such as a city or metropolitan area. A MAN typically connects multiple LANs together and provides high-speed connectivity within the area.

Example: A MAN may be used to connect multiple office buildings or campuses within a city.

Personal Area Network (PAN): A PAN is a network that connects personal devices, such as smartphones, laptops, and tablets, over a short distance. PANs are typically used for data exchange and communication between devices.

Example: Bluetooth is a common technology used to create PANs between devices, such as a smartphone and a wireless speaker or a laptop and a wireless mouse.

Hub

In computer networking, a hub is a simple networking device that is used to connect multiple devices in a network. It is a central connecting point for computers, printers, and other devices in a network.

When a device sends data to a hub, the hub forwards the data to all of the devices connected to it, regardless of whether the data is intended for a particular device or not. This is known as broadcasting. As a result, all devices connected to the hub receive the same data at the same time.

Hubs operate at the physical layer of the OSI model and are generally used in small networks. However, they have largely been replaced by more advanced networking devices such as switches and routers, which provide better performance and more advanced features.

It’s important to note that hubs can create network congestion as they forward all data to all devices on the network, which can cause unnecessary traffic and slow down network performance. For this reason, switches and routers are typically preferred over hubs in modern network design.

Switch

A switch is a networking device that is used to connect devices in a local area network (LAN). It works by forwarding data only to the device for which the data is intended, rather than broadcasting the data to all devices on the network like a hub.

A switch keeps track of the unique Media Access Control (MAC) addresses of the devices connected to it and uses this information to forward data only to the device it is intended for. This process is known as switching and it reduces unnecessary network traffic and improves network performance.

Switches are typically faster and more efficient than hubs because they only forward data to the devices that need it, whereas hubs broadcast all data to all devices. Switches can also provide additional features, such as Quality of Service (QoS) management, VLANs, and port mirroring.

Switches can be managed or unmanaged. Unmanaged switches are plug-and-play devices that require no configuration and are typically used in small networks. Managed switches are more advanced and offer more features, such as remote management, port configuration, and security options, making them suitable for larger, more complex networks.

Overall, switches are an essential component of modern computer networks and are used to connect computers, printers, servers, and other devices in a LAN, providing fast and efficient communication between them.

Router

A router is a networking device that is used to connect multiple networks together, such as LANs, WANs, and the internet. Its primary function is to forward data packets between networks based on the destination IP address, which makes it a key component of the internet and other large-scale networks.

Routers operate at the network layer of the OSI model and use routing tables and algorithms to determine the best path for data to take as it travels between networks. They can also provide additional features, such as network address translation (NAT), firewall protection, and virtual private network (VPN) connectivity.

When a device on one network sends data to a device on another network, the data is forwarded through the router. The router examines the destination IP address of the data packet and uses its routing table to determine the best path for the data to take. The router then forwards the data to the next network or router in the path until it reaches its final destination.

In addition to connecting different networks together, routers can also be used within a single network to create subnets, which can help to improve network performance and security by dividing the network into smaller, more manageable sections.

Overall, routers are an essential component of modern computer networks and are used to connect different networks together, enabling communication between devices on different networks and providing access to the internet.

Bridge

A bridge is a networking device that is used to connect two or more network segments together and selectively forward data between them. Bridges operate at the data link layer of the OSI model and are used to divide a large network into smaller, more manageable segments, which can improve network performance and security.

When a bridge receives a data frame from a device on one network segment, it examines the destination MAC address of the frame and compares it to its internal forwarding table, which contains a list of known MAC addresses and the network segment they belong to. If the destination MAC address is found in the forwarding table and belongs to a different network segment than the source MAC address, the bridge forwards the data frame to the appropriate network segment. If the destination MAC address is not found in the forwarding table, the bridge will flood the frame to all connected network segments.

Bridges can be used to create a variety of network topologies, including star, ring, and mesh. They can also be used in conjunction with other networking devices, such as switches and routers, to create more complex network architectures.

In modern networking, bridges have largely been replaced by switches, which offer more advanced features and better performance. However, bridges are still used in some legacy networks and can be useful in certain situations, such as connecting devices with different network protocols or extending the range of a network.

Gateway

A gateway is a networking device that connects two or more networks together and enables communication between them using different protocols. It is a key component of most computer networks and is essential for enabling communication between networks that use different protocols or architectures.

Gateways operate at the application layer of the OSI model and can provide a range of services, including protocol translation, address mapping, and network security. They are typically used to connect a local area network (LAN) to a wide area network (WAN), such as the internet.

When a device on a LAN sends data to a device on a remote network, the data is sent to the gateway, which then determines the best path for the data to take based on the destination network address. The gateway may need to perform protocol translation, such as converting TCP/IP packets to packets that are compatible with another protocol, in order to enable communication between the two networks. It may also need to perform address mapping, such as translating a private IP address used on the LAN to a public IP address that can be used on the internet.

In addition to enabling communication between networks, gateways can also provide network security by filtering and blocking unwanted traffic, such as malware or spam. They can also provide access control by requiring users to authenticate before accessing the network.

Overall, gateways are an essential component of modern computer networks and are used to enable communication between networks that use different protocols or architectures, provide network security, and control network access.

Repeater

A repeater is a networking device that is used to extend the range of a network by amplifying and regenerating signals that have degraded over distance. Repeaters operate at the physical layer of the OSI model and are used to increase the range of a network by boosting the strength of signals that have become weak due to attenuation, which is the loss of signal strength that occurs as signals travel over long distances.

When a signal is transmitted over a long distance, the signal strength decreases and the signal becomes weaker, which can result in errors and data loss. A repeater is used to regenerate the signal and boost its strength, so that it can be transmitted further over the network. Repeaters work by receiving the incoming signal, amplifying it, and then transmitting the amplified signal to the next segment of the network.

Repeaters are typically used in network architectures that rely on a bus topology, where all devices on the network share a single communication channel. In this type of network, the signal strength decreases as it travels down the communication channel, so repeaters are used to regenerate the signal and extend the range of the network.

It’s important to note that repeaters do not filter or modify the data that they transmit. They simply amplify and regenerate the signal, which means that any errors or data loss that occurred in the original signal will be present in the amplified signal. For this reason, repeaters are typically used in conjunction with other networking devices, such as switches and routers, which can filter and manage data as it travels through the network.

NIC

A Network Interface Card (NIC) is a hardware component that connects a computer to a network. It provides the physical connection between a computer and the network and allows the computer to communicate with other devices on the network. Here is a table that explains the difference between internal and external NICs:

Internal NICs are designed to be installed inside a desktop computer or server, and typically connect to the motherboard via a PCI or PCIe slot. They provide a dedicated, high-speed connection to the network and are often preferred for high-performance applications, such as servers or workstations.

External NICs, on the other hand, are designed to be connected to a computer via an external interface, such as USB or Ethernet port. They are commonly used in laptops or mobile devices, where internal NICs are not an option. They offer greater flexibility and portability and can be easily moved between devices. However, they may not provide the same level of performance as an internal NIC, especially for high-bandwidth applications.

Overall, both internal and external NICs serve the same basic purpose of connecting a computer to a network, but the choice between them depends on the specific requirements of the user and the device being used.

Modem

A modem (short for modulator-demodulator) is a device that converts digital signals from a computer into analog signals that can be transmitted over a phone line, cable line, or another communication channel. It also performs the reverse function of converting analog signals back into digital signals that can be understood by the computer. Here is a table that explains the functions of modulators and demodulators:

Modulators and demodulators are often combined into a single device known as a modem. The modulator is responsible for converting digital data into an analog signal that can be transmitted over a communication channel, such as a phone line or cable line. It does this by modulating a carrier signal, which is a continuous wave signal that is modified to represent the digital data.

The demodulator, on the other hand, is responsible for converting the analog signal back into digital data that can be understood by the receiving computer or device. It does this by demodulating the carrier signal, which involves extracting the original data from the modulated signal.

There are many different types of modulation and demodulation techniques used in modems, including amplitude modulation (AM), frequency modulation (FM), phase modulation (PM), and quadrature amplitude modulation (QAM). The specific technique used depends on the type of communication channel being used and the bandwidth requirements of the data being transmitted.

Examples of modems include cable modems, DSL modems, wireless modems, and dial-up modems. Cable and DSL modems are typically used for high-speed internet access, while wireless modems are used for mobile devices and remote locations. Dial-up modems are less common today, but are still used in some areas where high-speed internet access is not available.

Types of network topologies

In computer networking, topology refers to the physical or logical arrangement of devices on a network. There are several types of network topologies, including:

1. Bus topology: In a bus topology, all nodes are connected to a single communication line, known as a bus. Data is transmitted in both directions along the bus, and each node receives all transmissions but only processes the ones intended for it. This topology is easy to set up and inexpensive, but it can be prone to data collisions and is not as scalable as other topologies.
2. Star topology: In a star topology, all nodes are connected to a central hub or switch, which acts as a central point of communication. Data is transmitted between nodes through the hub or switch, and each node has its own dedicated connection to the hub or switch. This topology is highly reliable and scalable, but it can be more expensive to set up than other topologies.
3. Ring topology: In a ring topology, all nodes are connected to a single communication line in a closed loop or ring. Data is transmitted in one direction around the ring, and each node receives and processes the data intended for it before passing it on to the next node. This topology is highly reliable and can be very efficient, but it can be expensive to set up and is not as scalable as other topologies.
4. Mesh topology: In a mesh topology, all nodes are connected to each other in a fully interconnected network. Data can be transmitted directly between any two nodes in the network, and multiple paths can be used to transmit data, increasing reliability and fault tolerance. This topology is highly reliable and scalable, but it can be expensive to set up and can require significant network management.
5. Tree topology: In a tree topology, nodes are arranged in a hierarchical structure, with nodes branching off from a central root node. Each node in the tree can have its own subtree of nodes branching off from it. Data is transmitted between nodes through their parent nodes, and each node receives and processes data intended for it. This topology is highly scalable and efficient, but it can be expensive to set up and can be less reliable than other topologies if the root node fails.
6. Hybrid topology: A hybrid topology is a combination of two or more topologies. For example, a common hybrid topology is a star-bus topology, where multiple star topologies are connected to a central bus backbone. This topology can provide the benefits of both topologies, such as the reliability of a star topology and the scalability of a bus topology.

The choice of topology for a network depends on several factors, such as the number of nodes in the network, the distance between nodes, the bandwidth requirements of the network, and the level of fault tolerance and reliability needed.

Protocol

In computer networking, a protocol is a set of rules and procedures that govern how data is transmitted and received over a network. Protocols are necessary because different types of devices and software may use different methods to communicate with one another, and a standard set of protocols ensures that data can be exchanged reliably and efficiently.

There are many different protocols used in computer networking, each designed for a specific purpose. Some common protocols include:

1. TCP/IP (Transmission Control Protocol/Internet Protocol): This is the most commonly used protocol for transmitting data over the internet. TCP provides reliable, ordered, and error-checked delivery of data packets, while IP handles the routing of data between networks.
2. HTTP (Hypertext Transfer Protocol): This protocol is used to transfer web pages and other data over the World Wide Web.
3. FTP (File Transfer Protocol): This protocol is used to transfer files between computers on a network.
4. SMTP (Simple Mail Transfer Protocol): This protocol is used to send email messages between servers on the internet.
5. DNS (Domain Name System): This protocol is used to translate domain names into IP addresses, allowing users to access websites and other resources using human-readable names instead of numerical IP addresses.
6. DHCP (Dynamic Host Configuration Protocol): This protocol is used to automatically assign IP addresses and other network settings to devices on a network.

There are many other protocols used in computer networking, each designed for a specific purpose. By using standard protocols, devices and software from different vendors can communicate with one another and exchange data reliably and efficiently.

Data Transmission Modes

In computer networking, data transmission refers to the process of sending data from one device to another over a network. There are three primary modes of data transmission:

1. Simplex Mode: In simplex mode, data is transmitted in only one direction. For example, a TV signal is transmitted from a broadcast station to a TV set, but the TV set cannot send any data back to the station. Simplex mode is useful for applications where data needs to be transmitted in only one direction, and the receiver does not need to respond.
2. Half-Duplex Mode: In half-duplex mode, data can be transmitted in both directions, but only one device can transmit at a time. When one device is transmitting, the other device must listen and wait for its turn to transmit. Walkie-talkies and some two-way radio systems use half-duplex mode. Half-duplex mode is useful for applications where data needs to be transmitted in both directions, but only one device needs to transmit at a time.
3. Full-Duplex Mode: In full-duplex mode, data can be transmitted in both directions simultaneously. Both devices can transmit and receive data at the same time, allowing for more efficient communication. Most modern computer networks use full-duplex mode. Full-duplex mode is useful for applications where data needs to be transmitted in both directions, and both devices need to transmit data at the same time.

The choice of transmission mode will depend on factors like the application requirements, network topology, and available bandwidth. Simplex mode is useful for applications like broadcast TV or radio, where data only needs to be transmitted in one direction. Half-duplex mode is useful for applications like two-way radio communication, where both devices need to transmit data but not at the same time. Full-duplex mode is useful for applications like computer networking, where data needs to be transmitted in both directions simultaneously.

Parallel And Serial Transmission Mode

Data transmission can occur in either parallel or serial mode. Here is a comparison of the two modes in a table:

In parallel transmission, multiple bits of data are transmitted simultaneously over multiple wires. This allows for high data rates but requires more wires/cables and can have distance limitations due to synchronization issues. Parallel transmission is often used for transmitting data within a computer or between devices in close proximity, such as between a CPU and memory or between two devices connected by a parallel cable.

In serial transmission, data is transmitted one bit at a time over a single wire or channel. This allows for longer distances and is often used for transmitting data over a network or a communication link, such as over a telephone line. However, the data rate is lower than in parallel transmission, and it requires fewer wires/cables, making it less expensive.

Data Communication

Data communication in computer networks refers to the process of transmitting data from one device to another device over a network. It involves the following key elements:

1. Sender: The device that initiates the transmission of data is called the sender.
2. Receiver: The device that receives the transmitted data is called the receiver.
3. Transmission Medium: The physical medium that carries the transmitted data from the sender to the receiver is called the transmission medium. Examples of transmission media include wired media like copper wires, fiber optic cables, and wireless media like radio waves and microwaves.
4. Protocol: A protocol is a set of rules that governs the communication between devices. It defines the format of the data being transmitted, the method of transmission, and the procedures for error detection and correction.
5. Transmission Mode: The transmission mode refers to the direction in which data is transmitted. It can be simplex, half-duplex, or full-duplex.
6. Channel: A channel is a specific path through which data is transmitted. It can be a wired or wireless channel.

The process of data communication involves the following steps:

1. Data Generation: Data is generated by the sender device.
2. Encoding: The data is converted into a format that can be transmitted over the network.
3. Transmission: The encoded data is transmitted over the network through the transmission medium and the channel.
4. Decoding: The receiver device receives the transmitted data and converts it back to its original format.
5. Error Detection and Correction: The receiver checks the transmitted data for any errors and corrects them if necessary.
6. Delivery: The receiver delivers the correct data to the destination.

Data communication is a critical aspect of computer networks, and it allows for efficient communication and information exchange between devices. Different protocols and transmission modes are used depending on the specific application requirements and network topology.

IP (Internet Protocol)

IP (Internet Protocol) is a protocol that is used in computer networks to route data packets between devices. It is a layer 3 protocol in the OSI (Open Systems Interconnection) model and is responsible for the transmission of data packets across network boundaries.

IP is a connectionless protocol, which means that it does not establish a dedicated connection between devices before data transmission. Instead, it sends each data packet independently and uses the packet header to route the packet to its destination. The IP header contains important information such as the source and destination IP addresses, the protocol type, and other control information.

IP addresses are unique numerical identifiers assigned to devices on a network. They are used by the IP protocol to route data packets to their intended destination. There are two versions of IP in use today: IPv4 (Internet Protocol version 4) and IPv6 (Internet Protocol version 6). IPv4 uses 32-bit addresses, while IPv6 uses 128-bit addresses, allowing for a much larger number of unique addresses.

In addition to routing data packets, IP also provides some basic error detection and correction capabilities, such as checksums to verify the integrity of the data. However, it does not provide any mechanisms for ensuring the reliability or security of data transmission.

IP is a fundamental protocol in computer networking and is used in a wide range of applications, including the internet, local area networks (LANs), wide area networks (WANs), and other communication systems.

Addressing

Addressing in computer networking refers to the process of assigning unique identifiers to devices or applications on a network, which enables communication between them. In a network, every device and application must have a unique address to ensure that data is transmitted to the correct destination.

There are different types of addresses used in computer networking, including:

1. MAC Address: A Media Access Control (MAC) address is a unique hardware address assigned to a network interface controller (NIC) by its manufacturer. It is a 48-bit address and is used to identify devices on a local network.
2. IP Address: An Internet Protocol (IP) address is a unique numerical identifier assigned to a device on a network. It consists of a network address and a host address and is used to route data packets across networks.
3. URL: A Uniform Resource Locator (URL) is a string of characters that specifies the address of a resource on the internet, such as a webpage or file.
4. Email Address: An email address is a string of characters used to identify a user and their mailbox on an email system.
5. Port Number: A port number is a 16-bit number used to identify a specific process or application running on a device. It is used in conjunction with an IP address to enable communication between applications on different devices.

Addressing is a critical aspect of computer networking and is used in various applications, including web browsing, email, file sharing, and more. The assignment and management of addresses are typically performed by network administrators using different addressing schemes, such as Dynamic Host Configuration Protocol (DHCP) or manually configured static addressing.

Class of IP (Internet Protocol)

IP addresses are divided into classes based on their network prefix. There are five classes of IP addresses, which are as follows:

1. Class A: Class A IP addresses use the first octet to identify the network portion of the address, and the remaining three octets are used to identify hosts. The range of Class A addresses is from 1.0.0.0 to 126.0.0.0, and the default subnet mask is 255.0.0.0.
2. Class B: Class B IP addresses use the first two octets to identify the network portion of the address, and the remaining two octets are used to identify hosts. The range of Class B addresses is from 128.0.0.0 to 191.255.0.0, and the default subnet mask is 255.255.0.0.
3. Class C: Class C IP addresses use the first three octets to identify the network portion of the address, and the remaining octet is used to identify hosts. The range of Class C addresses is from 192.0.0.0 to 223.255.255.0, and the default subnet mask is 255.255.255.0.
4. Class D: Class D IP addresses are used for multicasting and use the range from 224.0.0.0 to 239.255.255.255.
5. Class E: Class E IP addresses are reserved for future use and are not currently used for general networking purposes.

The following table shows the address ranges and default subnet masks for each class of IP addresses:

Note that the address ranges and subnet masks are just the default values and can be changed by network administrators as needed.

IPV4 vs IPV6

IPv4 and IPv6 are two different versions of the Internet Protocol that are used to identify devices on a network. The main difference between them is the size of the IP address. IPv4 uses 32-bit addresses, while IPv6 uses 128-bit addresses, which allows for a much larger number of possible addresses.

The following table compares the features of IPv4 and IPv6:

In summary, IPv6 has a much larger address space, larger header size, supports extension headers, allows for sender-only fragmentation, supports both stateless address autoconfiguration and DHCPv6 for address assignment, has built-in support for Quality of Service (QoS), and mandates the use of IPSec for security.

ISP (Internet Service Provider)

An Internet Service Provider (ISP) is a company that provides access to the Internet for individuals, businesses, and other organizations. ISPs offer different types of Internet connections, such as dial-up, DSL, cable, fiber-optic, and satellite. They also provide various levels of service, such as different speeds, data caps, and customer support.

ISPs typically connect to the Internet backbone, which is a network of high-capacity, interconnected routers and switches that facilitate the flow of Internet traffic between different regions and countries. ISPs may also interconnect with each other through peering agreements, which allow them to exchange traffic directly instead of going through other networks.

In addition to providing Internet access, ISPs may offer other services such as email, web hosting, virtual private networks (VPNs), and cloud storage. They may also provide security services such as anti-virus and firewall protection.

ISPs are regulated by government agencies in many countries to ensure fair competition, consumer protection, and compliance with laws related to privacy, data retention, and censorship.

There are several categories of Internet Service Providers (ISPs) that provide access to the Internet:

1. Dial-up ISP: These ISPs offer Internet access through a telephone line using a modem. This type of connection is slow and becoming less common as newer technologies are developed.
2. DSL ISP: DSL (Digital Subscriber Line) ISPs provide Internet access over a telephone line, but with much higher speeds than dial-up. They use special equipment to separate voice and data traffic, allowing for simultaneous use of the phone line and the Internet.
3. Cable ISP: Cable ISPs provide Internet access over a cable television network. This type of connection offers higher speeds than DSL and is widely available in urban areas.
4. Fiber-optic ISP: Fiber-optic ISPs provide Internet access over a network of fiber-optic cables. This type of connection offers the highest speeds and is becoming more widely available.
5. Satellite ISP: Satellite ISPs provide Internet access through a satellite connection. This type of connection is available in areas where other types of Internet access are not available, but it can be expensive and may have limited bandwidth.
6. Wireless ISP: Wireless ISPs provide Internet access through a wireless connection, such as Wi-Fi or cellular networks. This type of connection is often used in rural areas where other types of Internet access are not available.

ISPs may also be categorized based on their size, such as national, regional, or local ISPs. Additionally, some ISPs may specialize in providing services to specific industries or types of customers, such as government agencies, schools, or small businesses.

Internet vs Intranet

In summary, the Internet is a global network that connects computers and devices around the world, while an intranet is a private network that is accessible only to authorized users within an organization. The Internet is public and less secure, while an intranet is owned by the organization and more secure. The Internet is used for communication and collaboration among individuals and organizations worldwide, while an intranet is used for communication, collaboration, and information sharing within an organization.

Network Architecture

In computer networking, network architecture refers to the design of a computer network and the way its components are arranged and interconnected. There are several common network architectures, including:

1. Peer-to-peer (P2P) network architecture: In this architecture, all devices are considered equal and can act as both clients and servers. Each device has its own resources, and users can access resources on other devices.
2. Client-server network architecture: In this architecture, there are dedicated servers that provide resources and services to client devices. Clients request resources from servers, which then respond to these requests. This architecture is commonly used in business environments.
3. Cloud-based network architecture: In this architecture, resources and services are provided through a cloud computing platform. Cloud providers host and manage the infrastructure, allowing users to access resources and services from anywhere with an internet connection.
4. Hybrid network architecture: This architecture combines different network architectures, such as a combination of P2P and client-server architectures. This allows organizations to take advantage of the benefits of different architectures while minimizing their disadvantages.

Network architecture can impact network performance, scalability, security, and management. Therefore, it’s important to choose the appropriate network architecture based on the organization’s needs and resources.

OSI Model

The OSI (Open Systems Interconnection) model is a conceptual framework that describes how communication happens between two computers over a network. The model is divided into seven layers, each of which performs a specific function in the communication process. Here is a brief overview of each layer:

1. Application layer: This layer provides access to network resources and services for end-users. It includes protocols such as HTTP, FTP, and SMTP.
2. Presentation layer: This layer is responsible for data representation and conversion between different data formats. It also handles data encryption and compression.
3. Session layer: This layer establishes and manages communication sessions between devices. It also provides services for synchronization, checkpointing, and recovery.
4. Transport layer: This layer provides reliable data transfer and error detection and recovery. It also handles flow control, segmentation and reassembly, and end-to-end communication.
5. Network layer: This layer is responsible for the logical addressing and routing of data packets between different networks. It determines the best path for data to travel between devices.
6. Data link layer: This layer provides error-free transfer of data frames between two devices on the same physical network. It also deals with flow control and provides access to the physical layer.
7. Physical layer: This layer deals with the physical connection between devices and the transmission of raw bits over a physical medium, such as wires or cables.

The OSI model provides a common language for describing and understanding network communication. By breaking down the communication process into distinct layers, it helps network engineers and developers to design, implement, and troubleshoot networks more effectively.

Guided vs unguided media

Guided and unguided media are two types of communication channels used in computer networks for transmitting data. Guided media use physical wires or cables to transmit signals, while unguided media use wireless signals to transmit data. Here is a comparison table of the two types of media:

Overall, the choice between guided and unguided media depends on various factors such as the required distance of transmission, desired data rates, and security concerns.

Transport layer and Datalink layer

Transport Layer and Data Link Layer are two different layers of the OSI Model in a computer network.

The main difference between the Transport Layer and Data Link Layer are:

In summary, the Transport Layer focuses on end-to-end communication between hosts and provides mechanisms to ensure reliability, while the Data Link Layer deals with communication between adjacent devices on the same network segment and provides error-checking and access control mechanisms.

Border Gateway Protocol (BGP)

Border Gateway Protocol (BGP) is a protocol used in computer networks to exchange routing information between different autonomous systems (ASes) on the internet. An autonomous system is a network under a single administrative domain with a common routing policy.

BGP is the protocol used by Internet Service Providers (ISPs) to connect their autonomous systems to the internet backbone. It is also used by large organizations with multiple networks and connections to other autonomous systems.

BGP is a path-vector protocol, which means that it uses a set of rules to determine the best path for packets to travel from one autonomous system to another. It considers factors such as the number of hops, bandwidth, and policies of the ASes involved in the routing decision.

BGP allows network administrators to control the flow of traffic between autonomous systems by setting policies for routing. This makes it a critical component of the internet’s infrastructure, as it allows networks to communicate with each other and ensures that traffic flows efficiently between different parts of the network.

One of the main challenges with BGP is ensuring its security, as it is vulnerable to attacks such as route hijacking and route leaks. To address these issues, security mechanisms such as Route Origin Validation (ROV) and Resource Public Key Infrastructure (RPKI) have been developed to improve the security of BGP routing.

FTP vs TFTP

FTP (File Transfer Protocol) and TFTP (Trivial File Transfer Protocol) are two protocols used for file transfer in computer networks. Here is a comparison of FTP vs TFTP:

FTP is a more feature-rich protocol that provides secure and reliable file transfer between hosts. It supports authentication and encryption and can transfer files of any size. However, it requires two separate connections for control and data, which can make it slower than TFTP.

TFTP, on the other hand, is a simpler protocol that is used mainly for transferring small files to or from a server. It does not provide authentication or encryption, which makes it less secure than FTP. It uses a single connection for both control and data, which makes it faster than FTP for small file transfers. However, it can only transfer files up to 32 MB in size and does not detect or correct transmission errors.

FDM vs TDM

FDM (Frequency Division Multiplexing) and TDM (Time Division Multiplexing) are two techniques used for transmitting multiple signals over a single communication channel in computer networks.

FDM is a technique that divides the frequency band of a communication channel into several smaller sub-bands, with each sub-band carrying a separate signal. Each signal is modulated onto its respective sub-band and transmitted simultaneously over the communication channel. FDM is commonly used in analog communications systems such as radio and television broadcasting.

TDM, on the other hand, divides the time interval of a communication channel into several smaller time slots, with each time slot carrying a separate signal. Each signal is transmitted in its respective time slot, and the signals are interleaved in time to form a composite signal that is transmitted over the communication channel. TDM is commonly used in digital communications systems such as telephone networks and digital subscriber lines (DSL).

The main difference between FDM and TDM is in the way they divide the communication channel. FDM divides the frequency band, while TDM divides the time interval. Both techniques have their advantages and disadvantages, and the choice between them depends on the specific application and the requirements of the communication system.

In summary, FDM divides the frequency band of a communication channel, allowing multiple signals to be transmitted simultaneously, while TDM divides the time interval of a communication channel, allowing multiple signals to be interleaved and transmitted over the same channel. The choice between FDM and TDM depends on the specific application and the requirements of the communication system.

RFC

RFC stands for “Request for Comments” and is a type of document used in computer networking to publish technical and organizational information, including protocols, procedures, and best practices. RFCs are typically written by engineers, researchers, and academics, and are used to document standards and specifications for computer networking technologies and protocols.

RFCs are published by the Internet Engineering Task Force (IETF) and other organizations, and are made available to the public for free. They are numbered sequentially, and the numbering system has been in use since the early days of the Internet. RFCs can be used to document new standards, update existing standards, and propose new protocols and technologies.

Many important networking protocols and technologies have been documented in RFCs, including the Transmission Control Protocol (TCP), the Internet Protocol (IP), the Simple Mail Transfer Protocol (SMTP), and the Domain Name System (DNS). The RFC process has played a critical role in the development of the Internet and has helped to ensure the interoperability and stability of the network.

TCP Reno and TCP Tahoe

TCP Reno and TCP Tahoe are two different versions of the TCP (Transmission Control Protocol) congestion control algorithm used in computer networking.

TCP Reno is an enhancement of the original TCP Tahoe algorithm and was introduced in 1990. It improves on TCP Tahoe by introducing the concept of fast recovery, which allows a TCP sender to recover more quickly from packet loss by sending new data packets without waiting for an acknowledgement of the lost packets. This can improve network performance in situations where packet loss is frequent, such as on congested networks.

TCP Tahoe, on the other hand, is the original TCP congestion control algorithm and was introduced in the 1980s. It uses a simple method to detect and respond to congestion by reducing the sender’s transmission rate when packets are lost or delayed. This algorithm is designed to be conservative, to prevent congestion from worsening and to ensure that the network remains stable.

Both TCP Reno and TCP Tahoe are widely used in computer networking today, and the choice between them depends on the specific requirements and characteristics of the network. TCP Reno is generally considered to be more aggressive in its approach to congestion control, while TCP Tahoe is more conservative.

Mastering DevOps: A Comprehensive Step-by-Step Guide to Elevate Your Skills and Enhance Your Workflow

1. Software Development Life Cycle (SDLC)

2. History Of DevOps

3. What is DevOps

4. DevOps LifeCycle

5. What is Git? — Git operation and command

6. What is Version Control System? — Git vs GitHub

7. The Most Important Linux Commands

8. Vagrant — The Complete Guide

9. The Power of Virtualization

10. Networking Guide

11. Bash Scripts: An In-Depth Tutorial

12. Architecture: Monolithic vs Microservices

13. CI/CD Workflow with Jenkins

14. Automating Your Infrastructure with Ansible

15. Docker Made Easy From Beginner to Advanced in One Guide

16. Creating a Custom Docker Image

17. Examples of Docker File With Various Application Stacks

18. Kubernetes A Beginner’s Tutorial

19. Kubernetes feature: Pods, Services, Replicasets, Controllers, Namespaces, Config, and Secrets

20. Terraform: Simplify Infrastructure Management

Level up your DevOps skills with our easy-to-follow tutorials, perfect for acing exams and expanding your knowledge. Stay tuned for more concepts and hands-on projects to boost your expertise!