COMPUTER NETWORKS

COMPUTER NETWORKS. UNIT – I OSI MODEL. PREPARED BY G.GEERTHIGA,AP/AD.

[Audio] The OSI model is a framework that standardizes how different network protocols interact with each other. It divides data communication into seven distinct layers. Each layer has specific responsibilities that ensure effective communication across a network. These layers work together to facilitate the exchange of data between devices. By breaking down complex communication processes into manageable parts, the OSI model makes it easier to understand and troubleshoot network issues. Its standardized approach enables devices from various manufacturers to communicate seamlessly with one another. This facilitates the creation of robust and reliable networks. The OSI model's seven-layer structure allows for flexibility and adaptability as new technologies emerge. It also promotes interoperability among different network devices. By providing a clear framework for network communication, the OSI model plays a crucial role in modern computing and networking..

OSI LAYERS. 7 6 5 4 3 2 Application Layer Presentation Layer session Layer Transport Layer Network Layer Data Link Layer Physical Layer Human-computer interaction layer, where applications can access the network services Ensures That data iS in a usable format and iS where data encryption occurs Maintains connections and is responsible for controlling ports and sessions Transmits data using transmission protocols including TCP and UDP Decides which physical path the data will take Defines the format of data on The network Transmits raw bit stream over the physical medium.

[Audio] The OSI model explains how data flows through a computer network. The OSI model consists of seven layers. Each layer has a specific function. The first layer is the physical layer. This layer deals with the physical aspects of transmitting data between two devices. It defines the transmission mode and whether it's simplex, half duplex, or full duplex. It also defines the topology configuration. The second layer is the data link layer. This layer is responsible for establishing and maintaining communication between two devices on the same network. It moves frames from one node to the next. The third layer is the network layer. This layer handles the routing of data between networks. It delivers individual packets from the source to the destination. These three layers work together to enable data communication between devices on the same network and between different networks..

[Audio] The transport layer is a critical component of the OSI model. It ensures that data is transmitted reliably and efficiently. The transport layer is responsible for breaking down data into smaller segments, assigning sequence numbers, and reassembling them when necessary. This process is crucial for maintaining the integrity of data during transmission. The transport layer also controls ports and sessions, allowing multiple processes to communicate simultaneously. This enables efficient use of network resources and prevents congestion. Furthermore, the transport layer facilitates smooth data transfer between devices by controlling the flow of data through the network. The transport layer plays a vital role in ensuring that data is delivered to its intended recipient..

[Audio] The company has been working on a new project for several years, but it has not yet been completed due to various reasons such as lack of resources and funding issues. Despite this, they have made significant progress in developing their products and services. The company's main goal is to provide high-quality products that meet customer needs and expectations..

[Audio] The physical layer is the first layer of the OSI model. It deals with the physical aspects of transmitting data between two devices. The physical layer defines the transmission mode, such as simplex, half-duplex, or full-duplex. It also determines the topology configuration of the network. In other words, it specifies how the devices are connected to each other. The physical layer transmits raw bit streams over the physical medium. This means that it sends the data in its simplest form, without any additional formatting or error-checking. The physical layer is responsible for ensuring that the data is transmitted reliably and efficiently. It does this by defining the transmission mode and specifying the topology configuration of the network. By doing so, it enables the data to be transmitted accurately and quickly. The physical layer plays a critical role in the functioning of the OSI model, as it sets the foundation for the rest of the layers to build upon. Without a well-designed physical layer, the entire OSI model would not function properly. Therefore, it is essential to carefully design and implement the physical layer to ensure the smooth operation of the network..

[Audio] The OSI model consists of seven distinct layers, each with specific responsibilities and functions. The Physical Layer (Layer 1) is responsible for transmitting data between devices over physical media such as cables and wireless links. The Data Link Layer (Layer 2) ensures error-free transmission of data frames between devices on the same network segment. The Network Layer (Layer 3) routes data packets between different networks using logical addressing and routing protocols. The Transport Layer (Layer 4) provides reliable data transfer between devices, ensuring that data is delivered in the correct order. The Session Layer (Layer 5) establishes, maintains, and terminates connections between applications running on different devices. The Presentation Layer (Layer 6) formats data for presentation purposes, such as encryption and compression. The Application Layer (Layer 7) provides services to end-user applications, such as email, file transfer, and web browsing. Each layer has specific protocols and standards that govern its operation, and these protocols are used to ensure that data is transmitted correctly and efficiently. The OSI model's layered structure allows for easier maintenance and troubleshooting of network issues, making it an essential tool for network administrators..

[Audio] The company has been working on a new project for several years, but it has not yet been completed due to various reasons such as lack of resources, funding issues, and other external factors. The project was initially planned to be completed within two years, but now it seems that it will take much longer than that. The company's management team has been trying to find ways to overcome these challenges, but so far they have had limited success. They have tried various approaches, including hiring more staff, increasing salaries, and improving communication among employees. However, none of these efforts have led to significant improvements in productivity or efficiency. Despite this, the company remains committed to completing the project, and they are exploring alternative solutions to overcome the current obstacles. They are also considering changes to their business model to better align with changing market conditions. The company's stakeholders, including investors and customers, are becoming increasingly impatient with the slow progress on the project. They are demanding more transparency and regular updates on the project's status. The company needs to address these concerns and provide clear information about its plans and timelines..

[Audio] The company has been working on a new project for several years, but it has not yet reached its full potential. The project involves developing a new type of aircraft that can fly at high speeds and maneuverability. The team has made significant progress, but they are still facing challenges in terms of cost and efficiency. The company is considering various options to address these issues, including partnering with other companies or investing in research and development..

[Audio] The Internet Protocol Suite, also known as TCP/IP, is a model used to describe how data is transmitted over the internet. The suite consists of four main protocols: IP, TCP, UDP, and ICMP. These protocols work together to enable data transfer between devices on the same network and between different networks. The suite provides a standardized way of transmitting data, which facilitates efficient communication. The protocols are designed to be flexible and adaptable, allowing them to handle varying network conditions. The suite has undergone several revisions since its introduction in the 1970s. The most recent revision occurred in 2013, when the Internet Engineering Task Force (IETF) updated the suite's protocols to improve performance and efficiency. The current version of the suite is widely adopted by organizations around the world. The suite's flexibility and adaptability have enabled it to remain relevant despite changes in technology and network configurations. The suite's ability to transmit data efficiently has facilitated global communication and collaboration. The suite's design allows for easy integration with existing infrastructure, making it an ideal choice for organizations seeking to expand their online presence. The suite's scalability and reliability have ensured its continued adoption..

[Audio] The OSI model is a conceptual framework that enables various communication systems to interact with one another seamlessly. It was developed by the International Organization for Standardization, or ISO, in 1984. The OSI model provides a structured approach to network design, enabling devices from different manufacturers to communicate effectively. The seven layers of the OSI model facilitate efficient and reliable data transmission over networks. Each layer operates independently, allowing devices to perform their functions without interference from other layers. This independence enables devices to work together efficiently, even when they are located far apart. The OSI model also helps to ensure that data is transmitted correctly, reducing errors and improving overall system performance. Furthermore, the OSI model provides a clear understanding of how data is transmitted over networks, making it easier for developers to create new applications and services. The OSI model is widely used in many industries, including telecommunications, finance, and healthcare. In addition, the OSI model is often used in conjunction with other networking standards, such as TCP/IP..

[Audio] The OSI model provides a structured approach to understanding the complexities of data communication. By dividing the process into seven distinct layers, it simplifies network design, learning, and troubleshooting. This standardized approach allows devices from different manufacturers to communicate effectively with each other. The OSI model also facilitates the creation of efficient, reliable, and secure networks. Its influence on network design and development is significant. The model's ability to break down complex processes into manageable components makes it an essential tool for network administrators. The OSI model's effectiveness in promoting interoperability among devices from various manufacturers is well-documented. The model's impact on network security is particularly noteworthy. The OSI model's structure helps to identify potential vulnerabilities and weaknesses in network systems. The model's comprehensive nature ensures that all aspects of network communication are considered. The OSI model's widespread adoption has led to the development of numerous networking protocols and standards. The model's influence extends beyond the realm of computer science, impacting fields such as telecommunications and engineering. The OSI model's significance cannot be overstated..