cns1.pdf

MODULE 1: Fundamental of Computer Networking NETWORKS - A network is a collection of network-enabled devices and allows them to communicate, typically made up of computers, switches, routers, printers, and servers. Network types PERSONAL AREA NETWOR...

MODULE 1: Fundamental of Computer Networking NETWORKS - A network is a collection of network-enabled devices and allows them to communicate, typically made up of computers, switches, routers, printers, and servers. Network types PERSONAL AREA NETWORK (PAN) - provides networking needs around an individual. An example of a PAN is where a smartphone, smartwatch, tablet, and laptop all connect and share data without the need to connect to an access point or other third-party network services. PAN networks typically use Bluetooth to communicate because it provides a low- power, short-range data-sharing capability. The network standards associated with a PAN are Bluetooth and IEEE 802.15. LOCAL AREA NETWORK (LAN) - provides networking needs around a single location. This location might be an organization's office, a school, a university, a hospital, an airport, and many others. Typically, a LAN is privately owned and needs authentication and authorization to access. Of the different classifications of a network, a LAN is by far the most commonly used. METROPOLITAN AREA NETWORK (WAN) - provides networking capabilities between two different locations within a city or metropolitan area to provide a single extensive network. Typically, a MAN requires a dedicated and secure connection between each LAN joined to the MAN. WIDE AREA NETWORK (WAN) - provides networking capabilities between two different geographical locations locally or worldwide. For example, a WAN is used to connect an organization's head office with branch offices all over the region. A WAN links multiple LANs together to create one super network. With a WAN, you use a virtual private network (VPN) to manage the connection between different LANs. Example – PUP SIS Note: Access Points - An access point (AP) is a term used for a network device that bridges wired and wireless networks. Consumer APs are often called a “wireless routers” because they typically also serve as both internet routers and firewalls. IEEE 802.15.4 - is a technical standard which defines the operation of a low-rate wireless personal area network (LR-WPAN). IEEE (Institute of Electrical and Electronics Engineers) Differences between LAN and WAN networks LAN WAN A LAN is a privately operated network typically contained A WAN is used to connect geographically separate offices to in a single building. each other. Multiple organizations might operate WANs. A LAN operates at speeds of 10 Gbps or higher. A WAN typically operates at speeds of less than 1 Gbps. A LAN is less congested compared to other network A WAN is more congested compared to other network types. types. A WAN typically requires the use of a third party to configure A LAN can be managed and administrated in-house. and set up, which increases cost FAQ: Why does WAN operating speed is slower? As data needs to travel across longer distances, it encounters more latency and attenuation Where do LAN gets internet connection? ISP (Internet Service Provider) connected to WAN Why is WAN congested? As it covers a lot more scope of area. How can Lan provide more internet speed than wan if wan is the source? Think of it as your water system in the neighborhood, water is flowing in certain speed, but due to small pipes that is connected to your house the water pressure increases, it is literally the same logic. Same with circuits. Network Topologies - A network topology describes the physical and logical composition of a network. TOPOLOGY – study of space. TYPES OF NETWORK TOPOLOGY Bus topology – all is connected to a single cable, The longer it gets, the higher the chance of signal dropout. Devices have to be physically located near each other. If there's a break in the bus cable, the whole network fails. Ring Topology - each network device is connected to its neighbor to form a ring. More resilient than the bus topology. Neighbor – connected by edges Mesh Topology - each network device connects to every other network device in the network. Increases the resilience of a network, but has the physical overhead of connecting all devices. There's a subtle difference between a physical mesh network and a logical one. The perception is that most modern networks are mesh based, since each device can see and communicate with any other device on the network. However, this topology describes a logical mesh network, and is primarily made possible by using network protocols. Star Topology - the most commonly used network topology. Each network device connects to a centralized hub or switch. Switches and hubs can be linked together to extend and build more extensive networks. This type of typology is, by far, the most robust and scalable. Ethernet - Ethernet is the most widely used technology for wired LAN connections. It provides a reliable and high-performance way to connect devices and share resources within a network. Types of ethernet Fast Ethernet Gigabit Ethernet 10 Gigabit Ethernet Terabit Ethernet Fast Ethernet Gigabit Ethernet 10 Gigabit Ethernet Terabit Ethernet (IEEE 802.3u) (IEEE 802.3ab) (IEEE 802.3ae) 100BASE-TX standard. 1000BASE-T 100 Mbps 10 times faster than the 10 Gbps 800 Gbps and 1.6 Tbps in the 100BASE-TX future. Stream media fiber optics Backward compatible  MODULE 2: Types of networks devices Types of network devices to use when you build a network A network can't exist unless each of the devices has the means of communicating with another. This fact applies whether it's your organization's network or more extensive networks, like the web. All networks are built on the same principles. (IEEE, ITU) Network Protocol A network protocol is basically a set of rules that devices on a network use to communicate with each other. Imagine it like a common language that allows these devices, even if they're made by different companies or run on different software, to understand each other and exchange information. Network Standards Network standards are essentially the agreed-upon rules that govern how devices communicate on a network. These rules ensure that different devices, regardless of manufacturer, operating system, or software, can understand each other and exchange information. Difference of Network protocol and Network standard? Think of it this way: Network standards are the established grammar rules, while protocols are like specific sentences that follow those rules. Standards provide the overall framework, ensuring different protocols can coexist and communicate effectively. Analogy: PROTOCOL – Law STANDDARD – law makers Network standards While network protocols provide a unified method for communication, network standards govern the hardware and software that uses them. Today, there are hundreds of thousands of hardware suppliers, yet all of their technology seamlessly integrates with your computer or network with minimal effort. Network standards provide a framework that enables the interoperability -ability of system between devices. Network standards improve the interoperability of different network-enabled devices and provide backward compatibility between product revisions and differing vendors. Official bodies that publish regulated standards are the International Telecommunication Union (ITU), the American National Standards Institute (ANSI), and the Institute of Electrical and Electronics Engineers (IEEE). It would be impossible to build networks and connect network-enabled devices reliably without network standards. The 802 family of standards The 802 specification covers all the physical networking standards for both Ethernet and wireless. Infrastructure Infrastructure – Facilities and facilitators Network infrastructure - refers to all the physical components and software that work together to enable communication and data exchange within a network. Network infrastructure There are several network standard-compliant devices that make up the structure of your networks. Depending on the network's size, you might use several of these devices to build the backbone of your network. These devices are: Repeaters Hubs Bridges Switches Routers Nearly all of these devices depend on a media access control or an Internet Protocol (IP) address to deliver data on the network. Media Access Control Address (MAC) – possibly not connected to internet The media access control (MAC) address is a unique identifier assigned to every network-enabled device at the time of manufacture. It's sometimes referred to as the burned-in address, the Ethernet hardware address, or a physical address. Hexadecimals Symbols: Hexadecimal uses 16 symbols: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, and then A, B, C, D, E, and F. Letters A-F represent values from 10 (A) to 15 (F). MAC The MAC address has a standard composition of six hexadecimal numbers separated by a colon or dash. The first three numbers of the MAC address define the manufacturer's organizationally unique identifier (OUI), The remaining three numbers uniquely identify the device. o For example, if the MAC address is AA-6A-BA-2B-68-C1 ▪ The OUI is AA-6A-BA ▪ The device ID is 2B-68-C1 IP address – connected to internet An IP address is a unique identifier assigned to a device on a network that uses the Internet Protocol (IP) for communication. In simpler terms, it's like an address for your device on the internet, allowing other devices to find and connect to you. IP Version IPv4: The older version, consisting of four numbers separated by dots (e.g., 192.168.1.1). IPv6: The newer version, designed to handle the growing number of internet-connected devices. It uses eight groups of hexadecimal digits separated by colons (e.g., 2001:0db8:85a3:0000:0000:8a2e:0370:7334). Function Identification: They uniquely identify devices on a network. Location: They can be used to determine the general location of a device (although not necessarily the exact physical address). Routing: They enable devices to send and receive data packets across networks. Difference of MAC and IP address IP addresses provide a logical way to identify devices for internet communication, while MAC addresses act as unique hardware identifiers for network interface cards within a local network. They work together to ensure efficient and secure data flow on a network. Data Packets - Data packets, also referred to as network packets or datagrams, are the fundamental units of information that travel across computer networks. DEVICES Repeater - A repeater is a two-port device that repeats network signals. Repeaters are used when network devices are some distance from each other. The repeater doesn't modify or interpret data packets before it resends them, and it doesn't amplify the signal. Instead, it regenerates the data packet at the original strength, bit by bit. Bridge - A bridge divides a network into network segments, and can filter and forward data packets between these segments. Bridges use the network device's MAC address to decide the data package's destination. Typically, a bridge is used to improve network performance by reducing unnecessary network traffic on network segments. Hub - A hub acts as a multiport repeater on a network. Hubs are used to connect more than one device and structure the layout of a network. For example, you can cascade hubs to create network branches, or as an endpoint to create a  star layout with multiple-user-type devices. Hubs contain multiple ports that act as an input/output Ethernet connection between the hub and a network device. A hub can operate at only one speed, which is the speed of the slowest network device on the network. It doesn't interpret or filter data packets, and sends copies of each data packet to all attached devices. Types of hubs Fast Ethernet: This hub is used for 100-Mbps networks and comes as Class I and Class II type hubs. The primary difference between the two is the amount of delay in data transmission. A Class I hub introduces a signal delay of up to 140-bit times. A Class II hub has a delay of up to 96-bit times. The delay allows for the transcoding of data between different base types. Only Class II hubs can be used in a hub-based network. Class II hubs increase the likelihood of packet collisions because of their higher speeds. Dual speed: With a traditional hub network, the slowest attached device governs the speed of the network. For example, if you had 10-Mbps and 100-Mbps devices connected to a network, the speed of the whole network was only 10 Mbps. Dual-speed hubs solve the problem by acting as a bridge between the two different-speed devices. Hubs are used for small ad-hoc networks of a few devices, but they're rarely used at an enterprise level. DEVICES Switch - A switch combines the functionality of a bridge and a hub. It segments networks and can interpret and filter packet data to send it directly to an attached network device. Switches use the network device's MAC address to decide the data package's destination. A switch operates in full-duplex mode, which means it can send and receive data to and from network devices at the same time. Features of switch Modern Ethernet-based switches offer more functionality and capabilities than an Ethernet hub. An Ethernet switch can adjust the connection speed of an inbound packet to match the connection speed of the destination network. Many switches now support Power over Ethernet (PoE). PoE enables network devices like Voice over IP (VoIP) phones to get power from the switch without needing a separate power supply. Other modules can be attached to the switch to enable functions like port mirroring, packet sniffers, and intrusion- detection systems. Types of Ethernet switch Unmanaged - This type of switch has no configuration capability, and is designed for small-office or home-office environments. Packet switching occurs automatically. Managed - This type of switch offers the means to adjust the configuration, behavior, and operation of the switch. Access to the switch configuration is either through a command-line interface (CLI) that uses Telnet or Secure Shell (SSH), Remote Console, or via a web interface. Access through CLI.  Definition of terms: VoIP - It's a technology that lets you make phone calls using your internet connection instead of a traditional landline. A Virtual LAN (VLAN) - is a logical grouping of devices on a physical network that can communicate with each other as if they were on a separate physical LAN. Imagine a large office building with a single network switch. VLANs allow you to create multiple virtual networks within that physical network, separating devices by department, function, or security needs. Bandwidth refers to the maximum amount of data that can be transferred across a network connection in a given amount of time. Bandwidth is typically measured in bits per second (bps), often represented in megabits per second (Mbps) or gigabits per second (Gbps). SNMP stands for Simple Network Management Protocol. It's a widely used protocol that allows network devices to communicate and share information with a network management system. SNMP is a fundamental tool for network management, providing a standardized way to collect valuable data from network devices for monitoring, troubleshooting, and maintaining network health. Managed Switch Features Quality of Service: Manage LAN traffic so that critical systems are given higher priority. An example is voice-data packets, which need to be delivered quickly. Virtual LANs: Create logical groups of devices in their own virtual LAN. Traffic in one virtual LAN doesn't cross over into another virtual LAN. This logical group of devices can improve the security and performance of the network. Spanning Tree Protocol (STP): Build resilience into your network by defining alternative network routes in case a cable or device fails. Port mirroring: Use with a network analyzer to diagnose network issues and problems. During setup, the switch exports a copy of the network traffic to a single port. Bandwidth rate-limiting: Allow fine control of the bandwidth used by specific ports. For example, allowing a high bandwidth for ports handling database or VoIP, and lower bandwidths for email. MAC address filtering: Control which network devices can be used or have access through the switch. SNMP client: Set up and configure SNMP with your network monitoring tools. Two subtypes of managed switches Smart: A smart switch is a halfway point between an unmanaged and a managed switch. They tend to offer only a web-based interface to manage the configuration. The available options are virtual LANs, port mirroring, and bandwidth rate limiting. Enterprise: The fully managed switch service previously described. With company. DEVICES Router - Routers link networks with different ranged addresses together. They can interpret and filter data packets, and then forward them to the correct network. Routers use the network device's IP address information to route the data package to its destination. Most routers can now detect issues with data traffic that flows to any attached network and route or reroute it around the issue. A router is also called a gateway. When you configure network devices, you usually configure them with a default gateway IP address. Interconnectivity Routers in an interconnected network maintain a routing table that lists the preferred route between each of the networks. The router acts as the start of authority for all the network devices on its network. Routing information is shared between routers by using a routing protocol like the Border Gateway Protocol (BGP). Border Gateway Protocol (BGP) The Border Gateway Protocol (BGP) is the workhorse routing protocol that keeps the internet running smoothly. It's a complex protocol, but here's a simplified explanation: Imagine the internet as a giant highway system. Each network is like a city, and BGP acts as the traffic director at the intersections, deciding which route data packets should take to reach their destination. Types Access routers: These routers tend to be low-cost devices with a simple routing need. They're typically used in a home or small satellite offices. Distribution routers: These routers compile traffic routing data from multiple routers. Distribution routers come with more significant memory and processing power. This type of router is designed to hold vast quantities of routing information. It's often used to manage and control the quality of service across a WAN. Edge routers: An edge router operates at the boundary between your network and other networks; for example, your local network and the internet. They act as gateways to filter traffic and route it internally or forward it based on the packet header. An edge router often comes with access control or firewalls to improve the security. It might also handle DHCP and DNS services. Core routers: Sometimes called enterprise routers, these routers are designed for higher bandwidths. They're used to connect different buildings or geographic locations together. Core routers tend to have fewer features than edge routers because their primary focus is on minimizing packet loss and preventing congestion. They tend to do packet forwarding to edge routers. Wireless router - This network device provides all the routing capabilities of a regular access router, but it also offers wireless access point functions. A wireless router or wireless access point is designed to provide a non-wired connection to your network. An edge router associated with your network handles any provision to access the internet or other networks. A wireless router lets you build a different type of network called a wireless local area network. A wireless router shouldn't be confused with a wireless modem. A wireless modem is what you receive from your ISP for your home or office. Wireless modems are typically combined with routers to allow you to create a private home or office network.  MODULE 3: Basic Addressing and OSI IP Address (IPv4) *It’s easier to communicate if you know your IP Address. Every node in the computer network is identified with the help of IP address Logical address Because IP address is assigned by a software or services, which makes it logical than fixed, unlike MAC address Can change based on the location of the device IP Address is assigned by: Manually – IP address is set manually by the user. Dynamically – IP address that changes automatically. Static – IP address that is constant. STATIC IP Usage Servers: Web servers, mail servers, game servers, or any server that needs to be accessible by other devices at all times benefit from static IPs. This ensures they have a permanent address that clients can always find. Remote access: If you need to remotely access a device on your network, like a security camera system or a computer you work from home on, a static IP makes it easier to establish a secure connection. Port forwarding: For applications that require incoming connections on specific ports (e.g., online gaming), a static IP is often required for proper configuration of port forwarding on your router. Business needs: Businesses might use static IPs for various purposes, such as managing VPN connections for remote employees or running internal applications that require consistent accessibility. Device monitoring: If you have critical devices on your network that need constant monitoring or management, a static IP simplifies the process of keeping track of them and ensuring they're always online. Represented in decimal and it has 4 octets Octet: An octet is a fundamental unit of digital information in computing. It consists of eight bits. Each bit can hold a value of either 0 or 1. (x.x.x.x) Collection of four octets: When referring to four octets together, it often signifies a specific data structure or value that uses 32 bits (4 x 8 bits). 0.0.0.0 to 255.255.255.255(32 bits) 255 is the maximum value representable by an 8-bit binary number. An 8-bit binary number consists of 8 bits (0s or 1s). With 8 bits, you have 2 possibilities for each bit (0 or 1), resulting in 2 ^ 8 (2 multiplied by itself 8 times) which equals 256 possible combinations. Since counting starts from 0, the usable range goes from 0 to 255. How to see IP address in real device? Open terminal Type “ ipconfig” Hit enter You’ll see IPv4 ANALOGY: IP Address – Location of the city MAC Address – Location of your house address MAC addressing  MAC stands for media access control Every node in the LAN is identified with the help of MAC address. Physical Address or Hardware Address. Unique Cannot be changed Assigned by the Manufacturer Represented in Hexadecimal Example: 70-20-84-00-ED-FC (48bits) Separator: hyphen (-) period(.), and colon (:) HEXA decimal Hex is a base-16 number system that uses digits 0-9 and letters A-F to represent values. 48 bits: A MAC address is comprised of 48 bits. Each bit can be either 0 or 1, representing the most basic unit of data in a computer. One hexadecimal digit can represent four binary bits (0s and 1s) So, for a 48-bit MAC address, we need 12 hexadecimal digits (48 bits / 4 bits/digit = 12 digits). This makes it more compact and easier to read than a long string of 0s and 1s. Putting it Together: Imagine a MAC address with the following binary representation (just an example, not a real MAC address) 00101101 01001010 10110100 11001001 00111111 10000001 Converted to hex format 0010 1101 0100 1010 1011 0100 1100 1001 0011 1111 1000 0001 2 D 4 A B 4 C 9 3 F 8 1 MAC ADDRESS: 2D-4A-BB-C9-3F-81 Much more readable for humans Possible combinations 2 raise to 48 making it a very large number and providing a vast addressing space for network devices. IP Address vs mac address IP ADDRESS MAC ADDRESS Needed for communication Needed for communication 32 bits 48 bits Represented in decimal Represented in hexadecimal Router needs IP Address to forward Data Switch needs MAC address to forward data Example: 10.10.23.56 Example: 70-20-84-00-ED-FC How to see MAC ADDRESS Desktop Environment Open terminal Type “ ipconfig/all” Hit enter Smartphones Open settings Under about phone Port Addresses ANALOGY Supposed you placed an order from a China shop in Lazada, and the parcel will reach your apartment within 3 days. How can you create an analogy of IP, MAC and port addresses here? Derivations from analogy Reaching your city = reaching our network (IP address) Reaching your Apartment = Reaching the host (MAC address) Reaching the right person/room = Reaching the right process (Port address) Port address or port number In a node many processes will be running. Data which are sent/received must reach the right process Every process in a node is uniquely identified using port numbers. Port = communication endpoint TYPES of PORT Number: Fixed port numbers Dynamic port Number (0 – 65535) Examples: Fixed Port Numbers: 25,80, etc. Dynamic Port Numbers: 62414 How to see port number Search in window: resmon Resmon stands for resource monitoring Observe there are many port numbers Try to open a lot of google chrome 3 key points to ponder Before sending the data, any node must Attach source IP address and destination IP address Attach source MAC address and destination MAC address Attach source port number and destination port number.