CH 2.docx

Computer Network Architecture Computer Network Architecture is defined as the physical and logical design of the software, hardware, protocols, and media of the transmission of data. Simply we can say that how computers are organized and how tasks are allocated to the computer. **The two types of...

Computer Network Architecture Computer Network Architecture is defined as the physical and logical design of the software, hardware, protocols, and media of the transmission of data. Simply we can say that how computers are organized and how tasks are allocated to the computer. **The two types of network architectures are used:** Computer Network Architecture Advertisement - Peer-To-Peer network - Client/Server network Peer-To-Peer network - Peer-To-Peer network is a network in which all the computers are linked together with equal privilege and responsibilities for processing the data. - Peer-To-Peer network is useful for small environments, usually up to 10 computers. - Peer-To-Peer network has no dedicated server. - Special permissions are assigned to each computer for sharing the resources, but this can lead to a problem if the computer with the resource is down.  Advantages Of Peer-To-Peer Network: - - - Disadvantages Of Peer-To-Peer Network: - - - - - - Client/Server Network - Client/Server network is a network model designed for the end users called clients, to access the resources such as songs, video, etc. from a central computer known as Server. - The central controller is known as a **server** while all other computers in the network are called **clients**. - A server performs all the major operations such as security and network management. - A server is responsible for managing all the resources such as files, directories, printer, etc. - All the clients communicate with each other through a server. For example, if client1 wants to send some data to client 2, then it first sends the request to the server for the permission. The server sends the response to the client 1 to initiate its communication with the client 2. Computer Network Architecture Advantages Of Client/Server network: - - - - Disadvantages Of Client/Server network: - Client/Server network is expensive as it requires the server with large memory. - A server has a Network Operating System(NOS) to provide the resources to the clients, but the cost of NOS is very high. - It requires a dedicated network administrator to manage all the resources. - If the server fails, clients may lose access to services - Managing servers requires skilled personnel. - If anyhow server goes down or crashes, entire will be affected by this. **Computer networking** A computer network is a collection of two or more computer systems that are linked together. A network connection can be established using either [[cable]](https://www.geeksforgeeks.org/what-is-coaxial-cable/) or [[wireless media.]](https://www.geeksforgeeks.org/wired-and-wireless-networking/) Hardware and software are used to connect computers and tools in any network. **Uses of Computer Networks** - - - - - **Types of Computer Networks** There are mainly five types of Computer Networks 1. 1. 1. 1. 1.  *Types of Computer Networks* **1. Personal Area Network (PAN)** [[PAN]](https://www.geeksforgeeks.org/overview-of-personal-area-network-pan/) is the most basic type of computer network. It is a type of network designed to connect devices within a short range, typically around one person. It allows your personal devices, like smartphones, tablets, laptops, and wearables, to communicate and share data with each other. PAN offers a network range of 1 to 100 meters from person to device providing communication. Its transmission speed is very high with very easy maintenance and very low cost. This uses[[ Bluetooth]](https://www.geeksforgeeks.org/bluetooth/)**, **[[IrDA]](https://www.geeksforgeeks.org/irda-infrared-data-association/)**, **and [[Zigbee]](https://www.geeksforgeeks.org/introduction-of-zigbee/) as technology. Examples of PAN are USB, computer, phone, tablet, printer, PDA, etc. Personal Area Network (PAN) *Personal Area Network (PAN)* **Types of PAN** - - **Advantages of PAN** - - - - - **Disadvantages of PAN** - - - - **Applications of PAN** - - - - - **2. Local Area Network (LAN)** LAN is the most frequently used network. A [[LAN ]](https://www.geeksforgeeks.org/lan-full-form/)is a computer network that connects computers through a common communication path, contained within a limited area, that is, locally. A LAN encompasses two or more computers connected over a server. The two important technologies involved in this network are [[Ethernet]](https://www.geeksforgeeks.org/local-area-network-lan-technologies/)** **and [[Wi-fi]](https://www.geeksforgeeks.org/what-is-wi-fiwireless-fidelity/).  It ranges up to 2km & transmission speed is very high with easy maintenance and low cost. Examples of LAN are networking in a home, school, library, laboratory, college, office, etc.  *Local Area Network (LAN)* **Advantages of a LAN** - - - - **Disadvantages of LAN** - - - - - **4. Metropolitan Area Network (MAN) ** A [[MAN]](https://www.geeksforgeeks.org/man-full-form-in-computer-networking/) is larger than a LAN but smaller than a WAN. This is the type of computer network that connects computers over a geographical distance through a shared communication path over a city, town, or metropolitan area. This network mainly uses FDDI, CDDI, and ATM as the technology with a range from 5km to 50km. Its transmission speed is average. It is difficult to maintain and it comes with a high cost. Examples of MAN are networking in towns, cities, a single large city, a large area within multiple buildings, etc. Metropolitan Area Network (MAN) *Metropolitan Area Network (MAN)* **Advantages of MAN** - - - - - **Disadvantages of MAN** - - - - **5. Wide Area Network (WAN)** WAN is a type of computer network that connects computers over a large geographical distance through a shared communication path. It is not restrained to a single location but extends over many locations. [[WAN]](https://www.geeksforgeeks.org/wan-full-form/) can also be defined as a group of local area networks that communicate with each other with a range above 50km. Here we use Leased-Line & Dial-up technology. Its transmission speed is very low and it comes with very high maintenance and very high cost. The most common example of WAN is the Internet.  *Wide Area Network (WAN)* **Advantages of WAN** - - - - **Disadvantages of WAN** - - - - C:\\Users\\Dell\\Pictures\\Screenshots\\Screenshot (2).png ========================================================== **What is Network Topology?** Topology defines the structure of the network of how all the components are interconnected to each other. There are two types of topology: physical and logical topology. **Types of Network Topology** Physical topology is the geometric representation of all the nodes in a network. There are six types of network topology which are Bus Topology, Ring Topology, Tree Topology, Star Topology, Mesh Topology, and Hybrid Topology.  **1) Bus Topology** Computer Network Topologies - The bus topology is designed in such a way that all the stations are connected through a single cable known as a backbone cable. - Each node is either connected to the backbone cable by drop cable or directly connected to the backbone cable. - When a node wants to send a message over the network, it puts a message over the network. All the stations available in the network will receive the message whether it has been addressed or not. - The bus topology is mainly used in 802.3 (ethernet) and 802.4 standard networks. - The configuration of a bus topology is quite simpler as compared to other topologies. - The backbone cable is considered as a **\"single lane\"** through which the message is broadcast to all the stations. - The most common access method of the bus topologies is **CSMA** (Carrier Sense Multiple Access). **CSMA:** It is a media access control used to control the data flow so that data integrity is maintained, i.e., the packets do not get lost. There are two alternative ways of handling the problems that occur when two nodes send the messages simultaneously. - **CSMA CD:** CSMA CD (**Collision detection**) is an access method used to detect the collision. Once the collision is detected, the sender will stop transmitting the data. Therefore, it works on \"**recovery after the collision**\". - **CSMA CA:** **CSMA CA (Collision Avoidance)** is an access method used to avoid the collision by checking whether the transmission media is busy or not. If busy, then the sender waits until the media becomes idle. This technique effectively reduces the possibility of the collision. It does not work on \"recovery after the collision\". **Advantages of Bus topology:** - **Low-cost cable:** In bus topology, nodes are directly connected to the cable without passing through a hub. Therefore, the initial cost of installation is low. - **Moderate data speeds:** Coaxial or twisted pair cables are mainly used in bus-based networks that support upto 10 Mbps. - **Familiar technology:** Bus topology is a familiar technology as the installation and troubleshooting techniques are well known, and hardware components are easily available. - **Limited failure:** A failure in one node will not have any effect on other nodes. **Disadvantages of Bus topology:** - **Extensive cabling:** A bus topology is quite simpler, but still it requires a lot of cabling. - **Difficult troubleshooting:** It requires specialized test equipment to determine the cable faults. If any fault occurs in the cable, then it would disrupt the communication for all the nodes. - **Signal interference:** If two nodes send the messages simultaneously, then the signals of both the nodes collide with each other. - **Reconfiguration difficult:** Adding new devices to the network would slow down the network. - **Attenuation:** Attenuation is a loss of signal leads to communication issues. Repeaters are used to regenerate the signal. **2) Ring Topology**  - Ring topology is like a bus topology, but with connected ends. - The node that receives the message from the previous computer will retransmit to the next node. - The data flows in one direction, i.e., it is unidirectional. - The data flows in a single loop continuously known as an endless loop. - It has no terminated ends, i.e., each node is connected to other node and having no termination point. - The data in a ring topology flow in a clockwise direction. - The most common access method of the ring topology is **token passing**. - **Token passing:** It is a network access method in which token is passed from one node to another node. - **Token:** It is a frame that circulates around the network. **Working of Token passing** - A token moves around the network, and it is passed from computer to computer until it reaches the destination. - The sender modifies the token by putting the address along with the data. - The data is passed from one device to another device until the destination address matches. Once the token received by the destination device, then it sends the acknowledgment to the sender. - In a ring topology, a token is used as a carrier. **Advantages of Ring topology:** - **Network Management:** Faulty devices can be removed from the network without bringing the network down. - **Product availability:** Many hardware and software tools for network operation and monitoring are available. - **Cost:** Twisted pair cabling is inexpensive and easily available. Therefore, the installation cost is very low. - **Reliable:** It is a more reliable network because the communication system is not dependent on the single host computer. **Disadvantages of Ring topology:** - **Difficult troubleshooting:** It requires specialized test equipment to determine the cable faults. If any fault occurs in the cable, then it would disrupt the communication for all the nodes. - **Failure:** The breakdown in one station leads to the failure of the overall network. - **Reconfiguration difficult:** Adding new devices to the network would slow down the network. - **Delay:** Communication delay is directly proportional to the number of nodes. Adding new devices increases the communication delay. **3) Star Topology** Computer Network Topologies - Star topology is an arrangement of the network in which every node is connected to the central hub, switch or a central computer. - The central computer is known as a **server**, and the peripheral devices attached to the server are known as **clients**. - Coaxial cable or RJ-45 cables are used to connect the computers. - Hubs or Switches are mainly used as connection devices in a **physical star topology**. - Star topology is the most popular topology in network implementation. **Advantages of Star topology** - **Efficient troubleshooting:** Troubleshooting is quite efficient in a star topology as compared to bus topology. In a bus topology, the manager has to inspect the kilometers of cable. In a star topology, all the stations are connected to the centralized network. Therefore, the network administrator has to go to the single station to troubleshoot the problem. - **Network control:** Complex network control features can be easily implemented in the star topology. Any changes made in the star topology are automatically accommodated. - **Limited failure:** As each station is connected to the central hub with its own cable, therefore failure in one cable will not affect the entire network. - **Familiar technology:** Star topology is a familiar technology as its tools are cost-effective. - **Easily expandable:** It is easily expandable as new stations can be added to the open ports on the hub. - **Cost effective:** Star topology networks are cost-effective as it uses inexpensive coaxial cable. - **High data speeds:** It supports a bandwidth of approx 100Mbps. Ethernet 100BaseT is one of the most popular Star topology networks. **Disadvantages of Star topology** - **A Central point of failure:** If the central hub or switch goes down, then all the connected nodes will not be able to communicate with each other. - **Cable:** Sometimes cable routing becomes difficult when a significant amount of routing is required. Advertisement **4) Tree topology**  Advertisement - Tree topology combines the characteristics of bus topology and star topology. - A tree topology is a type of structure in which all the computers are connected with each other in hierarchical fashion. - The top-most node in tree topology is known as a root node, and all other nodes are the descendants of the root node. - There is only one path exists between two nodes for the data transmission. Thus, it forms a parent-child hierarchy. **Advantages of Tree topology** - **Support for broadband transmission:** Tree topology is mainly used to provide broadband transmission, i.e., signals are sent over long distances without being attenuated. - **Easily expandable:** We can add the new device to the existing network. Therefore, we can say that tree topology is easily expandable. - **Easily manageable:** In tree topology, the whole network is divided into segments known as star networks which can be easily managed and maintained. - **Error detection:** Error detection and error correction are very easy in a tree topology. - **Limited failure:** The breakdown in one station does not affect the entire network. - **Point-to-point wiring:** It has point-to-point wiring for individual segments. **Disadvantages of Tree topology** - **Difficult troubleshooting:** If any fault occurs in the node, then it becomes difficult to troubleshoot the problem. - **High cost:** Devices required for broadband transmission are very costly. - **Failure:** A tree topology mainly relies on main bus cable and failure in main bus cable will damage the overall network. - **Reconfiguration difficult:** If new devices are added, then it becomes difficult to reconfigure. **5) Mesh topology** Computer Network Topologies - Mesh technology is an arrangement of the network in which computers are interconnected with each other through various redundant connections. - There are multiple paths from one computer to another computer. - It does not contain the switch, hub or any central computer which acts as a central point of communication. - The Internet is an example of the mesh topology. - Mesh topology is mainly used for WAN implementations where communication failures are a critical concern. - Mesh topology is mainly used for wireless networks. - Mesh topology can be formed by using the formula:\ **Number of cables = (n\*(n-1))/2;** Where n is the number of nodes that represents the network. Advertisement **Advantages of Mesh topology:** **Reliable:** The mesh topology networks are very reliable as if any link breakdown will not affect the communication between connected computers. **Fast Communication:** Communication is very fast between the nodes. **Easier Reconfiguration:** Adding new devices would not disrupt the communication between other devices. **Disadvantages of Mesh topology** - **Cost:** A mesh topology contains a large number of connected devices such as a router and more transmission media than other topologies. - **Management:** Mesh topology networks are very large and very difficult to maintain and manage. If the network is not monitored carefully, then the communication link failure goes undetected. - **Efficiency:** In this topology, redundant connections are high that reduces the efficiency of the network. Advertisement **6) Hybrid Topology**  - The combination of various different topologies is known as **Hybrid topology**. - A Hybrid topology is a connection between different links and nodes to transfer the data. - When two or more different topologies are combined together is termed as Hybrid topology and if similar topologies are connected with each other will not result in Hybrid topology. For example, if there exist a ring topology in one branch of ICICI bank and bus topology in another branch of ICICI bank, connecting these two topologies will result in Hybrid topology. **Advantages of Hybrid Topology** - **Reliable:** If a fault occurs in any part of the network will not affect the functioning of the rest of the network. - **Scalable:** Size of the network can be easily expanded by adding new devices without affecting the functionality of the existing network. - **Flexible:** This topology is very flexible as it can be designed according to the requirements of the organization. - **Effective:** Hybrid topology is very effective as it can be designed in such a way that the strength of the network is maximized and weakness of the network is minimized. **Disadvantages of Hybrid topology** - **Complex design:** The major drawback of the Hybrid topology is the design of the Hybrid network. It is very difficult to design the architecture of the Hybrid network. - **Costly Hub:** The Hubs used in the Hybrid topology are very expensive as these hubs are different from usual Hubs used in other topologies. - **Costly infrastructure:** The infrastructure cost is very high as a hybrid network requires a lot of cabling, network devices, etc. Client-Server Model =================== Last Updated : 19 Apr, 2024 - - - The Client-server model is a distributed application structure that partitions tasks or workloads between the providers of a resource or service, called servers, and service requesters called clients. In the client-server architecture, when the client computer sends a request for data to the server through the internet, the server accepts the requested process and delivers the data packets requested back to the client. Clients do not share any of their resources. Examples of the Client-Server Model are Email, World Wide Web, etc. **How Does the Client-Server Model Work?** In this article, we are going to take a dive into the **Client-Server** model and have a look at how the **Internet** works via, web browsers. This article will help us have a solid WEB foundation and help us easily work with[[ WEB technologies]](https://www.geeksforgeeks.org/web-technology/). - - So, it is the **Client **requesting something and the **Server** serving it as long as it is in the database. C:\\Users\\Dell\\AppData\\Local\\Packages\\Microsoft.Windows.Photos\_8wekyb3d8bbwe\\TempState\\ShareServiceTempFolder\\Screenshot (3).jpeg *Client Server Model* **How the Browser Interacts With the Servers?** **There are a few steps to follow to interacts with the servers of a client.** - - - - - -  *Client Server Request and Response* **Advantages of Client-Server Model** - - - **Disadvantages of Client-Server Model** - - - - ### **What is a File Server?** The central server in a computer network that is responsible for the storage and management of data files is called a **File Server.** In a File Server, users access a central storage space that acts as a medium to store the internal data ### Working of File Server: Let's first talk about the best hardware suitable for the foundation of the authentic file server. The hardware should offer enough space, working memory, and processing power. This helps the users in convenient file sharing, processing, and accessing files more quickly as possible. File Server *File Server* File Servers don't make any changes to the existing files. This is because they store the data as a heap of binary data and files in the form of *blobs(Binary Large Object).* So they don't perform any additional filtering or processing of data(executables, documents, photos, and video). The only way of working with File Servers is to make a file system that is accessible to clients. ### **Features of File Server:** - - - - - ### **Advantages:** - - - - - - ### **Disadvantages:** - - - - - Web Server Architecture ----------------------- Web server architecture refers to the structure and design of web servers, outlining how they handle incoming requests and deliver web content. There are two main approaches to web server architecture: **Working of Web Servers** -------------------------- A web server works in the following ways: - - - - -  To understand clearly how a web server works refer to the [How do Web Servers work?](https://www.geeksforgeeks.org/web-servers-work/) article. Types of Web Servers Softwares: ------------------------------- There are several types of web servers, each designed for specific purposes: **a. Apache HTTP Server : **Apache is one of the most popular open-source web servers globally, known for its flexibility and robustness. It's highly customizable and supports a wide range of modules and extensions. **b. Nginx : **Nginx is another widely used web server known for its speed and efficiency in handling concurrent connections. **c. Microsoft Internet Information Services (IIS) : **IIS is a web server developed by Microsoft for Windows servers. It's commonly used for hosting websites and web applications built on Microsoft technologies like ASP.NET. **d. LiteSpeed : **LiteSpeed is a commercial web server known for its high performance and security features. It's often used in hosting environments where speed and security are paramount. Features of Web Servers ----------------------- Web servers offer a range of features, including: - - - - - Benefits of Web Servers ----------------------- Using web servers offers several advantages, including: - - - - Uses of Web Server: ------------------- - - - - - When to Use Web Servers? ------------------------ You should consider using a web server when: 1. 1. 1. Steps to Use Web Server ----------------------- - **Step 2: Install and Configure**\ Install the chosen web server software on your server or hosting environment. Configure it by specifying settings such as document root, security rules, and virtual hosts. - - -