Basic Networking
- 1. System AD PROF. LUCITA C. GAMBOA, MIT
- 4. What Is Computer Networking? Computer networking is the practice of interfacing two or more computing devices with each other for the purpose of sharing data. Computer networks are built with a combination of hardware and software.
- 5. Computer Network Classification and Area Networks Computer networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans. Local area networks (LANs), for example, typically span a single home, school, or small office building, whereas wide area networks (WANs), reach across cities, states, or even across the world. The internet is the world's largest public WAN.
- 6. Network Design The two basic forms of network design are called client-server and peer-to- peer. Client-server networks feature centralized server computers that store email, web pages, files, and applications accessed by client computers and other client devices. Peer-to-peer network, conversely, all devices tend to support the same functions. Client-server networks are common in business and peer-to-peer networks are common in homes.
- 7. To establish network Access 1. Have a network interface that connects to your network access point. 2. Run your network services 3. Have access to network-broadcast device
- 8. Network Devices 1. Switch – A switch is a multiport bridge with a buffer and a design that can boost its efficiency(a large number of ports imply less traffic) and performance. A switch is a data link layer device. The switch can perform error checking before forwarding data, that makes it very efficient as it does not forward packets that have errors and forward good packets selectively to correct port only. In other words, switch divides collision domain of hosts, but broadcast domain remains same. Stright thru – A -A
- 9. Straight through A –A 568A colors WG G WO B WB 0 WBr Br 568B colors WO O WG B WB G WBr Br
- 10. LAN Switch Local area network switches or LAN switches are usually used to connect points on a company’s internal LAN. It is also known as a data switch or an Ethernet switch. It blocks the overlap of data packets running through a network by the economical allocation of bandwidth. The LAN switch delivers the transmitted data packet before directing it to its planned receiver. These types of switches reduce network congestion or bottlenecks by distributing a package of data only to its intended recipient Unmanaged Switch Unmanaged network switches are frequently used in home networks, small companies and businesses. It permits devices on the network to connect with each other, such as computer to computer or printer to computer in one location. An unmanaged switch does not necessarily need to be configured or watched. It is simple and easy to set up. If you want to add more Ethernet ports, you can use these plug and play types of switches in networking. Managed Switch
- 11. Managed Switch Compared to unmanaged switches, the advantage of managed switches is that they can be customized to enhance the functionality of a certain network. They offer some features like QoS (Quality of Service), Simple Network Management Protocol (SNMP) and so on. These types of switches in networking can support a range of advanced features designed to be controlled by a professional administrator. In addition, there is smart switch, a type of managed switch. It has some features that managed switch has, but are more limited. Smart network switch is usually used for the networking devices such as VLANs. PoE Switch PoE Gigabit Ethernet switch is a network switch that utilizes Power over Ethernet technology. When connected with multiple other network devices, PoE switches can support power and data transmission over one network cable at the same time. This greatly simplifies the cabling process. These types of switches in networking provide greater flexibility and you will never have to worry about power outlet when deploying network devices.
- 12. Stackable Switch Stackable switches provide a way to simplify and increase the availability of the network. For example, instead of configuring, managing, and troubleshooting eight 48-port switches individually, you can manage all eight like a single unit using a stackable Switches. With a true stackable switch, those eight switches (total 384 ports) function as a single switch—there is a single SNMP/RMON agent, single Spanning Tree domain, single CLI or Web interface. There are valuable operational advantages to use these types of switches in networking, such as you can create link aggregation groups spanning across multiple units in the stack, port mirror traffic from one unit in the stack to another, or setup ACLs/QoS spanning all the units.
- 13. 2. Hub – A hub is basically a multiport repeater. A hub connects multiple wires coming from different branches, for example, the connector in star topology which connects different stations. Hubs cannot filter data, so data packets are sent to all connected devices. In other words, collision domain of all hosts connected through Hub remains one. Also, they do not have intelligence to find out best path for data packets which leads to inefficiencies and wastage.
- 14. Types of Hub Active Hub:- These are the hubs which have their own power supply and can clean, boost and relay the signal along with the network. It serves both as a repeater as well as wiring centre. These are used to extend the maximum distance between nodes. Passive Hub :- These are the hubs which collect wiring from nodes and power supply from active hub. These hubs relay signals onto the network without cleaning and boosting them and can’t be used to extend the distance between nodes. Intelligent Hub :- It work like active hubs and include remote management capabilities. They also provide flexible data rates to network devices. It also enables an administrator to monitor the traffic passing through the hub and to configure each port in the hub.
- 15. 3. Routers – A router is a device like a switch that routes data packets based on their IP addresses. Router is mainly a Network Layer device. Routers normally connect LANs and WANs together and have a dynamically updating routing table based on which they make decisions on routing the data packets. Router divide broadcast domains of hosts connected through it.
- 16. 4. Gateway – A gateway, as the name suggests, is a passage to connect two networks together that may work upon different networking models. They basically work as the messenger agents that take data from one system, interpret it, and transfer it to another system. Gateways are also called protocol converters and can operate at any network layer. Gateways are generally more complex than switch or router.
- 17. 5. Brouter – It is also known as bridging router is a device which combines features of both bridge and router. It can work either at data link layer or at network layer. Working as router, it is capable of routing packets across networks and working as bridge, it is capable of filtering local area network traffic.
- 19. TCP/IP (Transmission Control Protocol/Internet Protocol) TCP/IP, or the Transmission Control Protocol/Internet Protocol, is a suite of communication protocols used to interconnect network devices on the internet. TCP/IP can also be used as a communications protocol in a private computer network (an intranet or an extranet).
- 20. A Network Address Translator (NAT) is the virtualization of Internet Protocol addresses. NAT helps improve security and decrease the number of IP addresses an organization needs Common protocols of TCP/IP include the following: •HTTP (Hyper Text Transfer Protocol) handles the communication between a web server and a web browser. •HTTPS (Secure HTTP) handles secure communication between a web server and a web browser. •FTP (File Transfer Protocol) handles transmission of files between computers. •IP Address •198.162.1.1 •ping
- 21. TCP/IP Model (Transmission Control Protocol- Internet Protocol) and OSI (Open System Interconnection) model help us in conceptualizing and standardizing so that computers can communicate over networks. These models help us in laying the theoretical and foundational basis of modern communication systems. The four layers of the TCP/IP model are: 1.Application Layer – to allow access to network resources. 2.Transport Layer – to provide reliable methods to process message delivery and error delivery. 3.Internet Layer – to move packets from source to destination and to provide networking. 4.Network Interface Layer – Responsible for the transmission between two devices on the same network.
- 22. 1.Application Layer: This layer helps in interacting with the Application program or the software which the user uses. Thus, it becomes closest to the end-user. It allows users to interact with other software applications. This layer interacts with software applications to implement a communicating component. How the data is interpreted by the end-user application program is not the concern or outside the scope of the TCP/IP model.
- 23. Some of the protocols used in the application layer are TELNET (Telecommunications Network), FTP (File Transfer Protocol), TFTP (Trivial File Transfer Protocol), NFS (Network File System), SMTP (Simple Mail Transfer Protocol), LPD (Line Printer Daemon), SNMP (Simple Network Management Protocol), DNS (Domain Name Service), etc.
- 24. 1.HTTP and HTTPS – HTTP stands for Hypertext transfer protocol. It is used by the World Wide Web to manage communications between web browsers and servers. HTTPS stands for HTTP-Secure. It is a combination of HTTP with SSL(Secure Socket Layer). It is efficient in cases where the browser need to fill out forms, sign in, authenticate and carry out bank transactions. 2.SSH – SSH stands for Secure Shell. It is a terminal emulations software similar to Telnet. The reason SSH is more preferred is because of its ability to maintain the encrypted connection. It sets up a secure session over a TCP/IP connection. 3.NTP – NTP stands for Network Time Protocol. It is used to synchronize the clocks on our computer to one standard time source. It is very useful in situations like bank transactions. Assume the following situation without the presence of NTP. Suppose you carry out a transaction, where your computer reads the time at 2:30 PM while the server records it at 2:28 PM. The server can crash very badly if it’s out of sync.
- 25. 2.Transport Layer: This layer helps in maintaining end-to-end communication across the network. It handles communication between hosts and provides multiplexing and reliability. This layer is built on the message which is received from the application layer. This layer determines data quantity and rates be sent over the network; it also sees to it that the data units are delivered in an error-free and sequential manner. The transport layer ensures that the message is received without any error; otherwise, the entire message is retransmitted again. Core Protocols: 1. Transmission Control Protocol (TCP) 2. User Datagram Protocol (UDP)
- 26. The two main protocols present in this layer are : 1.Transmission Control Protocol (TCP) – It is known to provide reliable and error-free communication between end systems. It performs sequencing and segmentation of data. It also has acknowledgment feature and controls the flow of the data through flow control mechanism. It is a very effective protocol but has a lot of overhead due to such features. Increased overhead leads to increased cost. 2.User Datagram Protocol (UDP) – On the other hand does not provide any such features. It is the go-to protocol if your application does not require reliable transport as it is very cost-effective. Unlike TCP, which is connection-oriented protocol, UDP is connectionless.
- 27. 3.Internet layer: This layer parallels the functions of OSI’s Network layer. It defines the protocols which are responsible for logical transmission of data over the entire network. The main functions of the internet layer are: Transmitting data packets to the link layer Optimal routing of data packets in an independent way from source to destination. Re-assembling out of order packets when they reach the destination. The errors which happen in the transmission of data packets and fragmentation is handled by this layer.
- 28. The main protocols residing at this layer are : 1.IP – stands for Internet Protocol and it is responsible for delivering packets from the source host to the destination host by looking at the IP addresses in the packet headers. IP has 2 versions: IPv4 and IPv6. IPv4 is the one that most of the websites are using currently. But IPv6 is growing as the number of IPv4 addresses are limited in number when compared to the number of users. 2.ICMP – stands for Internet Control Message Protocol. It is encapsulated within IP datagrams and is responsible for providing hosts with information about network problems. 3.ARP – stands for Address Resolution Protocol. Its job is to find the hardware address of a host from a known IP address. ARP has several types: Reverse ARP, Proxy ARP, Gratuitous ARP and Inverse ARP. 4. IGMP – responsible for the management of IP multicast groups
- 29. 4.Network Interface layer: This layer deals with the network on the physical level. It looks out for hardware addressing. The physical transmission of data is allowed due to the protocols present in this layer. It also includes how bits should optically be signalled by hardware devices (which directly interfaces with a network medium), like coaxial, optical fiber, or twisted-pair cables. A network layer is a combination of the data line and defined in the OSI reference model. How the data should be sent physically through the network, is decided by the network layer. When the transmission of data takes place between two devices on the same network, this layer is responsible for it.
- 30. OSI LAYER
- 31. o The OSI Model we just looked at is just a reference/logical model. It was designed to describe the functions of the communication system by dividing the communication procedure into smaller and simpler components. o But when we talk about the TCP/IP model, it was designed and developed by Department of Defense (DoD) in 1960s and is based on standard protocols. It stands for Transmission Control Protocol/Internet Protocol. The TCP/IP model is a concise version of the OSI model. It contains four layers, unlike seven layers in the OSI model.
- 32. In the Seven Layers Model, the networking system is divided into 7 layers with each layer interacting with the layer below and providing the functions to be used by the above layer. 7.Application – The Seventh layer is of application which the users can see and interact with directly, apps and browser are the prime examples of this. The more simplified way to understand is to know that this layer enables humans and software to interact. 6.Presentation – The sixth layer is for translating or formatting the data based either on the syntax or semantics based on what the application is programmed to accept and respond to. 5.Session – The fifth layer which is called the session layer is for starting and ending conversations between applications. You must have noticed how authentication is needed before you’re connected to a Wi-Fi network. That’s the work assigned to this layer. 4.Transport – The fourth layer is responsible for data transfer between the applications and across the network and also determining the amount of data that is to be sent and where it gets sent. 3.Network – The function of the third layer is to pack data along with the network address and hand it over to the transport layer which is the 4th 2.Data Link – Transmission errors are handled by the second layer and to stop the overwhelming of the data transfer from harming the receiver and sender. 1.Physical – The first layer is called the physical layer as it establishes the physical connection to the network using either electrical or mechanical interfaces.
- 35. While there are differences between the TCP-IP and the OSI Model, there are a few similarities: Both models are logical. They help in defining standards for networking. Since both models are based on layered architecture; in implementation, they divide the whole communication process into various layers. In both the models, a single layer stands for specific functionality, and that layer defines standards related to that specific functionality only. The protocols are defined in a layer-wise manner. The common standards and protocols are defined already by both models. This helps the manufacturers and operators to make and set up devices and network components. These devices and network components can coexist and work with devices and components made by other manufacturers.
- 36. Both help in dividing the communication network logically and physically into well-defined levels. This helps in making the troubleshooting process easier, as the complex functions now would be broken into simpler components. In many cases, there were already defined standards and protocols. In such cases, both these models adopt those existing standards instead of defining a new standard. For instance, IEEE had already defined Ethernet standards before the formal inception or adoption of both of these models. In that case, both these models adopted the IEEE Ethernet standards.
- 37. The layers of both these models are comparable to each other. The Physical and Data Link Layers of the OSI model corresponds to the Link Layer of the TCP/IP model. The application layer of the TCP/IP model is represented by the Session Layer, Presentation Layer, and the Application layer of the OSI model. Finally, in both the models, the Network and Transport Layers are at the same. The data is divided into packets, in both these models. Each of the packets may take the individual route from the source to the destination
- 38. Knowing how to configure and display network settings is essential when installing an Ubuntu server or desktop. It is also useful for troubleshooting problems with your Internet connection. The basic network configuration includes setting the IP address, the subnet mask for internal communication, and a gateway for connecting to external networks. I will give you examples of the basic configuration you need to set up a network in Ubuntu by either using the Command line or the Ubuntu Network Manager GUI. The steps have been tested on Ubuntu 18.04 LTS and Ubuntu 20.04 LTS but will work on newer Ubuntu versions too.
- 39. Networking Commands o Ping o traceroute o IP o netstat o ftp o wget o ssh
- 40. Basic network setup requires: Setting/Changing an IP address Setting up/Changing Hostname Editing a hosts file
- 41. Thank You