Lvl_3_ComputerNetwork_lec_03&04.pdf

Computer Networks Network Classifications, Transmission Media, and Devices Dr. Amr A. Alammari Lecture (3&4) Network Classification Network Classifications- Introduction Network Classification ▪ There are several types of computer networks, each designed...

Computer Networks Network Classifications, Transmission Media, and Devices Dr. Amr A. Alammari Lecture (3&4) Network Classification Network Classifications- Introduction Network Classification ▪ There are several types of computer networks, each designed to serve specific purposes and cover different geographical areas. ▪ Today when we speak about networks, we are generally referring to two primary categories: Local Area Networks Wide Area Networks ▪ However, it's important to note that there are also specific categories of networks with their own characteristics and purposes. ▪ These include networks such as PANs, CANs, SANs, etc. Network Classifications 02/03/2023 Network Classifications- LAN Local Area Network (LAN) ▪ LAN is a small and single-site network. - It connects devices inside a single building or inside buildings close to each other. - LAN size is limited to either the same building or within a small geographical area (a few kilometers), and this can be achieved using LAN extension devices, fiber optic cabling, wireless LANs and etc. ▪ Design and Management - LANs are typically owned, controlled, and managed by a single individual or organization. - LANs are designed to allow resources to be shared between computers. The resources to be shared can include, hardware (such as printers), and Software such as an application program. - One of the computers may be given a large-capacity disk and may become a server for clients. The software can be stored on this central server and used as needed by the whole group. Network Classifications- LAN Local Area Network (LAN) ▪ LANs can use various types of wired or wireless connections to interconnect devices. - Wired connections, such as Ethernet cables, are commonly used for high-speed and reliable connectivity. - Wireless connections, such as Wi-Fi, provide flexibility and mobility for devices within the network. ▪ LANs are widely used in various environments, including: - Home Networks. - Office Networks. - School/University Networks - Hospital Networks - Manufacturing Networks - Internet Cafe ▪ They enable efficient communication, resource sharing, and collaboration among devices and users within a localized area. Network Classifications WAN Wide Area Network Network Classifications- WAN Wide Area Network (WAN) ▪ WAN is a computer network that spans a large geographical area. - WAN is a geographically dispersed collection of LANs, data centers, remote offices, and other network sites. - It provides long-distance transmission over large geographic areas that may comprise a country, a continent, or even the whole world. - A WAN like the Internet spans most of the world. ▪ Design and Management - A network device called a router connects LANs to a WAN. - WANs often rely on telecommunications service providers or internet service providers (ISPs) to establish and maintain the connectivity between locations. - WANs utilize a combination of public and private communication links to establish connections between locations. These links can include leased lines, fiber optic cables, satellite connections, microwave links, and internet-based connections. Network Classifications- WAN Wide Area Network (WAN) ▪ WANs allow organizations to connect their various sites, such as headquarters, branch offices, data centers, and remote locations, into a unified network. ▪ WANs often employ redundant links and backup connections to ensure high availability and fault tolerance. ▪ In general, any organization or industry that requires connectivity, communication, and resource sharing between geographically dispersed locations can benefit from implementing a WAN infrastructure. ▪ Some examples include: - Research and Academic Networks - Government Networks - Healthcare Facilities - Educational Institutions - Corporate Networks Network Classifications MAN Metropolitan Area Network Network Classifications- MAN Metropolitan Area Network (MAN) ▪ A MAN is a network that interconnects users in a geographic area larger than that covered by LAN but smaller than the area covered by a WAN. - It provides connectivity to multiple locations within a defined geographic region, normally covering the area inside a town or a city. - The size of a MAN can vary depending on the specific requirements and the size of the city or metropolitan area it serves. ▪ Design and Management - A network device called a bridge can be used to interconnect multiple LANs or network segments within the MAN. - MANs use various wired and wireless connection technologies to interconnect different locations. - MANs can be owned and operated by telecommunication service providers or by private organizations that require dedicated connectivity for their operations. - Local ISPs often deploy MANs to provide high-speed internet connectivity to businesses and residential areas within a city. Network Classifications- MAN Metropolitan Area Network (MAN) ▪ MANs often serve as the intermediate layer between LANs and WANs. - They connect LANs within a specific metropolitan area or city and provide a gateway to connect with larger regional or global WAN infrastructures. ▪ MANs are designed to provide data communication services, such as internet connectivity, file sharing, and resource access, to organizations, institutions, or businesses within a defined geographical region. Some other examples include: - Cable broadband - MANs in Educational Institutions - A network of fire stations - A network of community colleges - A network of government agencies - Corporate MANs Network Classifications- Comparison Difference between LAN, MAN, and WAN Parameters LAN MAN WAN Acronym Local Area Network Metropolitan Area Network Wide Area Network Speed Up to 10 Mbps or 100 Mbps Up to 34 Mbps or 155 Mbps Up to 1 Gbps to 100 Gbps Transmission Media Twisted pair, Coaxial cable Fiber optics Microwave, Radio, Satellite Connecting Devices Hub, Switch Bridge Router, Multi-layer Switches Location office or groups of buildings Covers the area of a single city Network of Networks, Across the country or around the world. Topology Bus, Ring Distributed Queue Dual Bus (DQDB) ATM, Frame Relay, SONNET Cost Less costly More costly Costlier Advantage Software and resources can MAN can cover a wider area than a WAN can connect the computer be centrally managed LAN to a wider area geographically Disadvantage Area covered is limited It includes the cost of the cutting- WAN network is more edge technology employed complicated and complex 02/03/2023 Network Classifications PAN Personal Area Network Network Classifications- PAN Personal Area Network (PAN) ▪ PAN refers to a small network of communication. - These are used in a limited range, which is in reachability of individual person. - It is designed for personal use and typically covers a small area, such as within a room or within the range of a person's immediate surroundings. ▪ Design and Management - PANs interconnect electronic devices, such as smartphones, tablets, laptops, wearable devices, and peripherals, within an individual person's workspace in a wireless or wired manner. - A wired PAN connecting devices using USB cables or Ethernet cables within a limited area. - Wireless PANs, also known as WPANs, use wireless technologies like Bluetooth or Zigbee to establish connections between devices. Network Classifications- PAN Personal Area Network (PAN) ▪ While devices within a PAN can exchange data with each other, PANs typically do not include a router and thus do not connect to the Internet directly. - A device within a PAN, however, can be connected to a local area network (LAN) that then connects to the Internet. ▪ Examples: - Wireless Keyboards and Mice - Health and Fitness Monitoring (Fitness Trackers) - Home Automation (smart lighting systems, security cameras) - Personal Device Interactions (Smartwatches, Bluetooth Headsets) - Gaming Controllers Transmission Media Transmission Media- Introduction Transmission Media ▪ How data transmitted across the network? - The transmission media of a computer network describes the material substances that carry energy waves, which include the data being transferred. - The two main categories are wired, or guided, which uses physical cables, and wireless, or unguided, which uses electromagnetic waves that can travel through a vacuum or a medium, such as air. Physical Media Types ▪ The most commonly used wired connections use: - Twisted-pair cables - Coaxial cables - Fiber optic cables Transmission Media Twisted-Pair Cables ▪ Consist of individual copper wires that are twisted into pairs. The wires are wrapped in an insulation material. ▪ Twisted-pair cables are usually categorized into shielded cables (STP) and unshielded cables (UTP) based on their construction. ▪ UTP cables: - More susceptible to electromagnetic interference (EMI) and crosstalk, less costly, easier to install, and generally sufficient for many common network applications, especially in office environments with lower levels of interference. ▪ STP Cables: - The shielding is typically made of metallic foil or braided copper, which helps to reduce electromagnetic interference (EMI) and crosstalk between adjacent pairs. The shielding protects the signals from external sources of interference, such as electrical noise or electromagnetic radiation, improving the overall signal quality and reducing the risk of data corruption or signal degradation. 02/03/2023 Transmission Media Twisted-Pair Cables- Example ▪ Cat7's pairs are individually shielded in addition to a shielded jacket over the whole cable, allowing it to operate at much higher frequencies with less interference. - Cat is short for "Category." The transmission rate of an Ethernet cable is measured by frequency (in Hz) and divided into Classes of performance. These "Classes" are served by "Categories" of cable. - Each version is more robust, better shielded, and capable of faster data transmission than its predecessor. Transmission Media Coaxial Cables 1 ▪ Coaxial cable is a very robust shielded copper cable. - The center conductor is much thicker than a twisted-pair conductor and 2 is surrounded by an outer shield/conductor that serves to greatly improve signal strength and integrity. 3 - A layer of dielectric material, either foam or solid, generally separates the two conductors. - The center conductor carries the carrier signal and the outer conductor generally is used only for electrical grounding and is maintained at 0 volts. ▪ Specific types of coaxial cables often are referred to by RG number (e.g., RG-6, RG-8, and RG-58). 4 - RG referring to Radio Guide which is the original military specification for coaxial cables. 1: Center Conductor - RG number refers to the cable's diameter. However, 2: Dielectric 5 measurements do vary. 3: Foil Shield - Generally, a higher RG numbers means a thinner central 4: Braded Shield conductor, and vice versa. 5: Outer Jacket 02/03/2023 Transmission Media Coaxial Cables RG Cable example - RG-6/U is a common type of coaxial cable. It's used in a wide variety of residential and commercial applications, including cable television, home internet, and more. ▪ LMR (Land Mobile Radio) Coaxial Cable - LMR is the newer generation of RF coaxial cables. They provide greater flexibility, ease of installation, and lower cost. They're used as transmission lines for antennas on missiles, airplanes, satellites, and communications. - The LMR number is a rough estimate of the cable’s thickness. LMR cable example - LMR 240 is an outdoor-rated flexible low-loss communications coax. It's designed for short feeder runs for applications like GPS, WLAN, and mobile antennas. 02/03/2023 Transmission Media Fiber Optic Cables 1 ▪ A fiber optic cable consists of a central fiberglass core surrounded by several layers of protective material - This type of cable transmits light rather than electronic signals. A light-emitting diode (LED) or laser is used to create the light pulses. 2 - The transmission speed of a fiber optic cable is much faster 3 compared to the other cables. ▪ There are several different types of fiber optic cables, each with its own characteristics and applications. 4 5 - Single-Mode Fiber (SMF): have a small core size and are designed to carry a single mode of light. They provide high bandwidth and are 1: Core capable of transmitting data over long distances with low signal loss. 2: Cladding - Multimode Fiber (MMF): has a larger core size and can carry multiple 3: Coating modes of light. They are suitable for shorter-distance transmissions, 4: Strength Member such as within buildings or campuses. 5: Outer Jacket Transmission Media Wireless Connections ▪ Wireless connections rely on the transmission of signals through the air using EM waves. - No physical medium is necessary for wireless signals, making them a very versatile way to build a network. ▪ The most commonly used wireless connections use radio waves, microwaves, and infrared waves. - Other hardware for the transmission of wireless signals through the air is required. ▪ Radio Waves - EM waves ranging in frequencies between 3 kHz and 1 GHz are normally called radio waves. - This makes radio waves a good candidate for long- distance communication. - Radio waves are used for multicast communications, such as radio and television, and paging systems. Transmission Media Wireless Connections ▪ Microwave - EM waves having frequencies between 1 and 300 GHz are called microwaves. Due to their unidirectional properties, microwaves are very useful when unicast (one-to-one) communication is needed. - Unicast communication such as cellular telephones, satellite networks, and wireless LANs. ▪ Infrared - Infrared waves, with frequencies from 300 GHz to 400 THz can be used for short-range communication. - Infrared waves, having high frequencies, cannot penetrate walls. This advantageous characteristic prevents interference between one system and another. - Infrared signals can be used for short-range communication in a closed area using line-of-sight propagation. Transmission Media Wireless and physical Media Comparison ▪ Wireless and physical media have distinct characteristics and advantages. - Some of these characteristics (Bandwidth, distance, and price) are compared in the table below. ▪ Wireless communication offers mobility and flexibility but has limitations in range, coverage, and potential for interference. ▪ Physical media communication provides higher data rates, greater range, and improved reliability but lacks the mobility and flexibility of wireless connections. - The choice between the two depends on the specific requirements, environment, and application. Network Devices Network Devices Modem and NIC Network Devices- Modem Modems ▪ A modem is used to modulate and demodulate data signals. - A modem (short for modulator-demodulator) is a device that converts digital signals from a computer or network into analog signals suitable for transmission over analog communication channels. - It modulates digital data into analog signals for transmission and demodulates received analog signals back into digital data. - Modems operate at the physical layer (Layer 1) and the data link layer (Layer 2) of the OSI model. - Modems are commonly used to connect computers or networks to the internet via telephone lines, cable lines, or other communication mediums. - While all computer data is digital, signals over certain types of connections are analog. A modem is used to encode digital information onto an analog carrier signal and to decode the transmitted information back to digital. Network Devices- Modem Video Network Devices- NIC Network Interface Card ▪ A network interface card (NIC), also known as a network adapter, is a piece of hardware that allows individual computers to physically connect to a network. - An NIC contains the electronic circuitry required for a wired connection (Ethernet) or a wireless connection (Wi-Fi). ▪ It provides the physical interface between the device and the network, allowing data to be transmitted and received. - NIC operates at the data link layer (Layer 2) of the OSI model. - It encapsulates data into frames and sends them over the network. The NIC also receives incoming frames, extracts the data, and delivers it to the appropriate higher-layer protocols or applications running on the computer/device. Network Devices- NIC Video Network Devices- Modem vs NIC Modem vs NIC ▪ While the Network Interface Card (NIC) is a device used to connect a computer/device to a local area network (LAN). The modem is a device used to connect a computer/device to a wide area network (WAN), such as the internet, and performs digital- to-analog and analog-to-digital conversion for data transmission over communication channels. Network Devices Repeaters, Hubs, Bridges, and Switches Network Devices- Repeater Repeaters ▪ A repeater is a device that receives electronic signals, cleans them, and retransmits them at a higher power level. - Signals transmitted over cable tend to degrade over long distances. - Repeaters are used o regenerate or amplify the signal in long-distance transmission. ▪ Repeaters operate at the physical layer of the network and are used to overcome the limitations of signal attenuation and loss over long distances in wired networks. ▪ A repeater receives a weak or degraded signal, cleans it up, and retransmits it at a higher power level to extend the network's range. Network Devices- Hub Hub ▪ A hub is a networking device used to connect multiple devices directly to the network using cables. - A hub is a simple wired networking device that operates at the physical layer of the network. - When the hub receives data at one of its ports, it distributes the data to the other ports in the network. Typically, a hub sends all the data it receives to all the other ports. ▪ Hub serves as a central connection point for multiple devices in a network, allowing them to communicate with each other. - However, when a device sends data to a hub, it broadcasts the data to all other connected devices, regardless of the intended recipient. - This makes hubs inefficient for larger networks and prone to collisions. As a result, hubs have become less common in modern networks. Network Devices- Hub Video Network Devices- Bridges Bridges ▪ Bridges are networking devices that divide up the network into different segments to manage the amount of traffic. - This prevents unnecessary traffic from entering other parts of the network and reduces congestion. - As a network becomes more complex, bridges make sure your network speed doesn’t drop dramatically. ▪ A bridge is a networking device that operates at the data link layer of the network. It connects two or more network segments or LANs (Local Area Networks) and forwards data packets between them. - Bridges examine the MAC addresses (Media Access Control) of incoming data packets and make forwarding decisions based on the destination MAC address. - They help to segment and isolate network traffic, improving overall network performance and reducing congestion. Network Devices- Bridge Video Network Devices- Switch Switches ▪ Switch is an intelligent hub that knows the addresses of the connected devices. It contains many ports to connect different network segments. - They are similar to hubs but offer greater performance. - When a network contains a large number of devices, switches are needed instead of hubs to make sure the communications between devices do not slow down. - Contrary to hubs, switches send the data it receives only to specific ports. ▪ A switch is a more advanced networking device that operates at the data link layer. - It connects multiple devices in a network and uses MAC addresses to forward data packets selectively. - Switches are commonly used in modern Ethernet networks. Network Devices- Switch Video Network Devices- Switch vs Bridge Switches vs Bridges ▪ While bridges and switches both connect network segments, switches offer more advanced features, such as higher port density, VLAN support, and improved performance through full- duplex operation. ▪ Switches are widely used in modern networks, providing greater flexibility, scalability, and management capabilities compared to traditional bridges. Network Devices Routers and Gateways Network Devices- Router Routers ▪ Routers are communication devices used to connect two different networks. - A router sorts incoming data and distributes it to the correct destination. - It connects multiple networks, such as LANs or the Internet, and forwards data packets between them based on IP addresses. Routers examine the destination IP address of incoming packets and make routing decisions to determine the best path for the data to reach its destination. ▪ A router is a networking device that operates at the network layer of the network. - The Internet uses numerous routers to direct all the traffic taking place. - While routers are used to connect different networks, they only work if the network protocols are the same. Network Devices- Router Video Network Devices- Gateway Gateways ▪ A gateway interfaces networks that use different protocols. - A gateway is a networking device that acts as an interface between different networks that use different protocols or technologies. - It translates data between these networks to enable communication. Gateways can be hardware devices, software applications, or a combination of both. - They are commonly used to connect local networks to the internet, translating between the protocols used in the local network (such as Ethernet) and the protocols used on the internet (such as TCP/IP). ▪ You can think of a gateway as a router that includes protocol translators. - The terms 'router' and 'gateway' are often used interchangeably, but it is important to remember that only gateways make it possible to connect networks using different protocols. Network Devices- Gateway Video Network Devices Firewalls Network Devices- Firewalls Firewalls ▪ A firewall is a network security device that monitors incoming and outgoing network traffic and decides whether to allow or block specific traffic based on a defined set of security rules. - The primary purpose of a firewall is to protect a computer network from unauthorized access, malicious activities, and potential threats. ▪ A firewall can be hardware, software, software-as- a-service (SaaS), public cloud, or private cloud. ▪ At its most basic, a firewall is essentially the barrier that sits between a private internal network and the public Internet. ▪ When properly configured, a firewall allows users to access any of the resources they need while simultaneously keeping out unwanted users, hackers, viruses, worms or other malicious programs trying to access the protected network. Network Devices- Firewalls Video Network Devices Server Network Devices- Server Server ▪ A server is a dedicated computer equipped with specific programs and/or hardware that enables it to offer services to other computers (clients) on its network. - Servers play a critical role in network infrastructure, providing essential services and resources to clients. ▪ Servers are designed to handle and respond to client requests, allowing users to access shared resources, run applications, store and retrieve data, and perform various network-related tasks. ▪ They handle complex server processes, from managing multiple user queries every second, hosting content-heavy websites, and setting up a shareable drive for network devices. Network Devices- Server Video Textbooks ▪ Data Communications and Networking Behrouz Forouzan.