Lesson 1: Differentiate between LANs & WANs PDF

# Lesson 1: Differentiate between LANs & WANs ## 1.1 Ethernet:- ### 1.1.1 What is Ethernet? Ethernet is the traditional technology for connecting devices in a wired local area network (LAN) or wide area network (WAN). It enables devices to communicate with each other via a protocol, which is a set...

# Lesson 1: Differentiate between LANs & WANs ## 1.1 Ethernet:- ### 1.1.1 What is Ethernet? Ethernet is the traditional technology for connecting devices in a wired local area network (LAN) or wide area network (WAN). It enables devices to communicate with each other via a protocol, which is a set of rules or common network language. Ethernet describes how network devices format and transmit data so other devices on the same LAN or campus network can recognize, receive and process the information. An Ethernet cable is the physical, encased wiring over which the data travels. Compared to wireless LAN (WLAN) technology, Ethernet is typically less vulnerable to disruptions. It can also offer a greater degree of network security and control than wireless technology because devices must connect using physical cabling. ### 1.1.2Why is Ethernet used? Ethernet initially grew popular due to its inexpensive price tag when compared to the competing technology of the time, such as IBM's token ring. As network technology advanced, Ethernet ability to evolve and deliver higher levels of performance. Ethernet initially ran over coaxial cables. Early Ethernet connected multiple devices into network segments through hubs -- Devices responsible for transporting network data -- using either a daisy chain or star topology. Currently, a typical Ethernet LAN uses special grades of twisted-pair cables or fiber optic cabling. ### 1.1.3Advantages and disadvantages of Ethernet:- Ethernet has many benefits for users, which is why it grew so popular. However, there are a few disadvantages as well. #### Advantages of Ethernet 1. Relatively low cost. 2. Backward compatibility. 3. Resistant to noise. 4. Good data transfer quality. 5. Speed. 6. Reliability. 7. Data security, as common firewalls can be used. #### Disadvantages of Ethernet 1. Intended for smaller, shorter distance networks. 2. Limited mobility. 3. Use of longer cables can create crosstalk. 4. Does not work very well with real-time or interactive applications. 5. Troubleshooting is hard when trying to trace which specific cable or node is causing the issue. ### 1.1.4How Ethernet works? IEEE specifies in the family of standards called IEEE 802.3 that the Ethernet protocol touches both physical connectivity and the sent data. Ethernet defines two units of transmission: packet and frame. The frame includes the payload of data being transmitted as well as the physical media access control (MAC) addresses of both the sender and receiver. Like with other network types, involved computers must include a network interface card (NIC) to connect to Ethernet. ## 1.2NIC:- ### 1.2.1 What is NIC? A network interface card (NIC) is a hardware component without it the computer cannot be connected over a network. It is a circuit board installed in a computer that provides a dedicated network connection to the computer. It is also called network interface controller, network adapter or LAN adapter. - **Purpose** 1. NIC allows wired communications. 2. NIC allows communications between computers connected via local area network (LAN) as well as communications over large-scale network through Internet Protocol (IP). ### 1.2.2Types of NIC Cards:- NIC cards are of two types - **Internal Network Cards:** - In internal networks cards, motherboard has a slot for the network card where it can be inserted. - It requires network cables to provide network access. Internal network cards are of two types. - The first type uses Peripheral Component Interconnect (PCI) connection, while the second type uses Industry Standard Architecture (ISA). - **External Network Cards:** - In desktops and laptops that do not have an internal NIC, external NICs are used. ## 1.3 Local area network (LAN):- The term local area network (LAN) is commonly used to describe a network of devices in a limited area (a house, office, building...). This type of network is usually capable of achieving high data transfer rate (up to 10 Gbps!) at low cost. Examples of this type of network are a small office network inside a single building or your home network. - The following figure shows a typical LAN. [Image of LAN with connection to the internet.] > One of the most popular LAN technologies is Ethernet. Most LAN networks use two common connectivity methods Ethernet and wireless networks. Wireless LANs are also known as WLANS. ## 1.4 What Is WAN? And How Wide Area Networks Function? A wide area network (also known as WAN), is a large network of information that is not tied to a single location. WANs can facilitate communication, the sharing of information and much more between devices from around the world through a WAN provider. WANs can be vital for international businesses, but they are also essential for everyday use, as the internet is considered the largest WAN in the world. These networks are often established by service providers that then lease their WAN to businesses, schools, governments or the public. These customers can use the network to relay and store data or communicate with other users, no matter their location, as long as they have access to the established WAN. Access can be granted via different links, such as virtual private networks (VPNs) or lines, wireless networks, cellular networks or internet access. As organizations grow and become international, WANs allow them to communicate between branches, share information and stay connected. When employees travel for work, WANs allow them to access the information they need so they are able to carry out their essential daily functions without delay. Employees from anywhere can use a business's WAN to share data, communicate with coworkers or simply stay connected to the greater data resource center for that organization. WANs also help organizations share information with customers Students at universities might rely on WANs to access library databases or university research. And every day, people rely on WANs to communicate, bank, shop and more. ## 1.5 What's the Difference Between Wide Area Network (WAN) and Local Area Network (LAN)? Whereas WANs can exist globally, without ties to a physical location through the use of a leased network provider, LANs exist within a limited area. LANs can be used to access a greater WAN (such as the internet), but only within the area where the LAN's infrastructure can reach. ## 1.6 What Is MAN? The term metropolitan area network is used to describe a network in a single metropolitan area, hence the name. This type of network is usually bigger than a LAN and smaller than a WAN. An example of this type of network would be a network that connects two company offices inside the same city. # Lesson 2: troubleshoot data communications systems We to define some important network parameters ## 2.1 MAC & IP addresses:- ### MAC address:- A Media Access Control (MAC) address is a 48-bit (6 bytes) address that is used for communication between two hosts in an Ethernet environment. It is a hardware address, which means that it is stored in the firmware of the network card. Every network card manufacturer gets a universally unique 3-byte code called the Organizationally Unique Identifier (OUI). Manufacturers agree to give all NICs a MAC address that begins with the assigned OUI. The manufacturer then assigns a unique value for the last 3 bytes, which ensures that every MAC address is globally unique. MAC addresses are usually written in the form of 12 hexadecimal digits. For example, consider the following MAC address: D8-D3-85-EB-12-E3 Every hexadecimal character represents 4 bits, so the first six hexadecimal characters represent the vendor (Hewlett Packard in this case). ### IP address:- An IP address is a 32-bit number that identifies a host on a network. Each device that wants to communicate with other devices on a TCP/IP network needs to have an IP address configured. For example, in order to access the Internet, your computer will need to have an IP address assigned (usually obtained by your router from the ISP). An IP address is usually written in the form of four decimal numbers separated by periods (e.g., 10.0.50.1). The first part of the address represents the network the device is on (e.g., 10.0.0.0), while the second part of the address identifies the host device (e.g., 10.0.50.1). In contrast to MAC address, an IP address is a logical address. It can be configured manually or it can be obtained from a DHCP server. ## 2.2troubllshooting:- ### 2.2.1What is Network Troubleshooting? Network troubleshooting is the combined measures and processes used to identify, diagnose and solve problems within a computer network. It is a logical process that network engineers use to resolve network problems and improve network operations. Troubleshooting is an iterative process, the more data you collect and analyze, the higher the likelihood of developing a correct hypothesis ### 2.2.2 Troubleshooting Methodology:- A troubleshooting model to effectively address network issues that will arise and equip you in handling such problems. Cisco has broken down the process into eight methodical steps: 1. Define the problem. 2. Gather detailed information. 3. Consider probable cause for the failure. 4. Devise a plan to solve the problem. 5. Implement the plan. 6. Observe the results of the implementation. 7. Repeat the process if the plan does not resolve the problem. 8. Document the changes made to solve the problem. ### 2.2.3 Troubleshooting Methods:- Here are some other troubleshooting methods that can be used to efficiently isolate the root cause of the network issue and immediately implement the best solution to it. 1. **Compare Configurations** - A lot of network performance issues are usually caused by human errors, and the initial way to troubleshoot problems is to check if there are configuration changes that have been made in the network. 2. **Trace the Path** - One of the most used troubleshooting tools is sending a ping to your destination device. There is another ICMP-based tool that shows you where the ICMP packet stopped in the network, and that is the traceroute. 3. **Swap-out Components** - Usually, network outages are caused by hardware failures ranging from a simple ethernet cable wear and tear to full-on equipment failure. When this happens, we have no choice but to replace -