Tools for teaching computer networking and hardware concepts / Nurul Sarkar, . learn computer networking and hardware fundamentals better and feel more. Lauren has decided to review basic network concepts with her coworkers as hardware or software failure that causes information or applications to be. Networking concepts and hardware. Basic Communications Model Standards are needed at all Layers. User Layer. Application Layer. Computer (Transport).
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Technology Education. Network Basics Figure: The definition of a computer network: a set of transmission paths . Network Hardware. • Network interface. Physical (Hardware) Networking Components. to familiarize the reader with the fundamentals of computer architecture, networking, and computer. HARDWARE & NETWORKING (6 WEEKS). 1. COMPUTER HARDWARE. Introduction to basic electronics, subassembly of PC. Subassembly of Motherboard.
Main article: Node networking Apart from any physical transmission media there may be, networks comprise additional basic system building blocks, such as network interface controllers NICs , repeaters , hubs , bridges , switches , routers , modems , and firewalls. Any particular piece of equipment will frequently contain multiple building blocks and perform multiple functions.
Network interfaces[ edit ] An ATM network interface in the form of an accessory card. A lot of network interfaces are built-in. A network interface controller NIC is computer hardware that provides a computer with the ability to access the transmission media, and has the ability to process low-level network information.
For example, the NIC may have a connector for accepting a cable, or an aerial for wireless transmission and reception, and the associated circuitry. In Ethernet networks, each network interface controller has a unique Media Access Control MAC address—usually stored in the controller's permanent memory.
The size of an Ethernet MAC address is six octets. The three most significant octets are reserved to identify NIC manufacturers. These manufacturers, using only their assigned prefixes, uniquely assign the three least-significant octets of every Ethernet interface they produce.
Repeaters and hubs[ edit ] A repeater is an electronic device that receives a network signal , cleans it of unnecessary noise and regenerates it. The signal is retransmitted at a higher power level, or to the other side of an obstruction, so that the signal can cover longer distances without degradation.
In most twisted pair Ethernet configurations, repeaters are required for cable that runs longer than meters. With fiber optics, repeaters can be tens or even hundreds of kilometers apart. A repeater with multiple ports is known as an Ethernet hub. Repeaters work on the physical layer of the OSI model.
Repeaters require a small amount of time to regenerate the signal. This can cause a propagation delay that affects network performance and may affect proper function. As a result, many network architectures limit the number of repeaters that can be used in a row, e. Hubs and repeaters in LANs have been mostly obsoleted by modern switches. Bridges[ edit ] A network bridge connects and filters traffic between two network segments at the data link layer layer 2 of the OSI model to form a single network.
This breaks the network's collision domain but maintains a unified broadcast domain. Network segmentation breaks down a large, congested network into an aggregation of smaller, more efficient networks.
Remote bridges, where the connecting link is slower than the end networks, largely have been replaced with routers.
Switches[ edit ] A network switch is a device that forwards and filters OSI layer 2 datagrams frames between ports based on the destination MAC address in each frame.
It can be thought of as a multi-port bridge.
If an unknown destination is targeted, the switch broadcasts to all ports but the source. Switches normally have numerous ports, facilitating a star topology for devices, and cascading additional switches. Routers[ edit ] A typical home or small office router showing the ADSL telephone line and Ethernet network cable connections A router is an internetworking device that forwards packets between networks by processing the routing information included in the packet or datagram Internet protocol information from layer 3.
The routing information is often processed in conjunction with the routing table or forwarding table. A router uses its routing table to determine where to forward packets. A destination in a routing table can include a "null" interface, also known as the "black hole" interface because data can go into it, however, no further processing is done for said data, i. Modems[ edit ] Modems MOdulator-DEModulator are used to connect network nodes via wire not originally designed for digital network traffic, or for wireless.
To do this one or more carrier signals are modulated by the digital signal to produce an analog signal that can be tailored to give the required properties for transmission. There are a great number of protocols in use extensively in networking, and they are often implemented in different layers.
Port: A port is an address on a single machine that can be tied to a specific piece of software. It is not a physical interface or location, but it allows your server to be able to communicate using more than one application.
Firewall: A firewall is a program that decides whether traffic coming into a server or going out should be allowed. A firewall usually works by creating rules for which type of traffic is acceptable on which ports.
Generally, firewalls block ports that are not used by a specific application on a server. It is a way to translate requests that are incoming into a routing server to the relevant devices or servers that it knows about in the LAN. This is usually implemented in physical LANs as a way to route requests through one IP address to the necessary backend servers.
It is a means of connecting separate LANs through the internet, while maintaining privacy. This is used as a means of connecting remote systems as if they were on a local network, often for security reasons.
Networking Basics: Part 1 - Networking Hardware
There are many other terms that you may come across, and this list cannot afford to be exhaustive. We will explain other terms as we need them. At this point, you should understand some basic, high-level concepts that will enable us to better discuss the topics to come. Network Layers While networking is often discussed in terms of topology in a horizontal way, between hosts, its implementation is layered in a vertical fashion throughout a computer or network.
What this means is that there are multiple technologies and protocols that are built on top of each other in order for communication to function more easily. Each successive, higher layer abstracts the raw data a little bit more, and makes it simpler to use for applications and users. It also allows you to leverage lower layers in new ways without having to invest the time and energy to develop the protocols and applications that handle those types of traffic.
The language that we use to talk about each of the layering scheme varies significantly depending on which model you use. Regardless of the model used to discuss the layers, the path of data is the same. As data is sent out of one machine, it begins at the top of the stack and filters downwards.
At the lowest level, actual transmission to another machine takes place. At this point, the data travels back up through the layers of the other computer. Each layer has the ability to add its own "wrapper" around the data that it receives from the adjacent layer, which will help the layers that come after decide what to do with the data when it is passed off.
This model defines seven separate layers. The layers in this model are: Application: The application layer is the layer that the users and user-applications most often interact with. Network communication is discussed in terms of availability of resources, partners to communicate with, and data synchronization. Presentation: The presentation layer is responsible for mapping resources and creating context. It is used to translate lower level networking data into data that applications expect to see.
Session: The session layer is a connection handler. It creates, maintains, and destroys connections between nodes in a persistent way.
Transport: The transport layer is responsible for handing the layers above it a reliable connection. In this context, reliable refers to the ability to verify that a piece of data was received intact at the other end of the connection.
Top 100 Networking Interview Questions & Answers
This layer can resend information that has been dropped or corrupted and can acknowledge the receipt of data to remote computers. Network: The network layer is used to route data between different nodes on the network. It uses addresses to be able to tell which computer to send information to.
This layer can also break apart larger messages into smaller chunks to be reassembled on the opposite end. Data Link: This layer is implemented as a method of establishing and maintaining reliable links between different nodes or devices on a network using existing physical connections.
Physical: The physical layer is responsible for handling the actual physical devices that are used to make a connection. This layer involves the bare software that manages physical connections as well as the hardware itself like Ethernet. As you can see, there are many different layers that can be discussed based on their proximity to bare hardware and the functionality that they provide.
It defines the four separate layers, some of which overlap with the OSI model: Application: In this model, the application layer is responsible for creating and transmitting user data between applications. The applications can be on remote systems, and should appear to operate as if locally to the end user. The communication is said to take place between peers.
Transport: The transport layer is responsible for communication between processes. This level of networking utilizes ports to address different services.
It can build up unreliable or reliable connections depending on the type of protocol used. Internet: The internet layer is used to transport data from node to node in a network. This layer is aware of the endpoints of the connections, but does not worry about the actual connection needed to get from one place to another.
IP addresses are defined in this layer as a way of reaching remote systems in an addressable manner. Link: The link layer implements the actual topology of the local network that allows the internet layer to present an addressable interface.
It establishes connections between neighboring nodes to send data. This made it easier to implement and allowed it to become the dominant way that networking layers are categorized. Interfaces Interfaces are networking communication points for your computer. Each interface is associated with a physical or virtual networking device.
Typically, your server will have one configurable network interface for each Ethernet or wireless internet card you have. In addition, it will define a virtual network interface called the "loopback" or localhost interface.
This is used as an interface to connect applications and processes on a single computer to other applications and processes. You can see this referenced as the "lo" interface in many tools. Many times, administrators configure one interface to service traffic to the internet and another interface for a LAN or private network.
In DigitalOcean, in datacenters with private networking enabled, your VPS will have two networking interfaces in addition to the local interface. The "eth0" interface will be configured to handle traffic from the internet, while the "eth1" interface will operate to communicate with the private network. Protocols Networking works by piggybacking a number of different protocols on top of each other. In this way, one piece of data can be transmitted using multiple protocols encapsulated within one another.
We will talk about some of the more common protocols that you may come across and attempt to explain the difference, as well as give context as to what part of the process they are involved with. We will start with protocols implemented on the lower networking layers and work our way up to protocols with higher abstraction.This is why switches have almost completely replaced hubs.
You can create what is known as a cross over cable. Cellular and PCS systems use several radio communications technologies. With fiber optics, repeaters can be tens or even hundreds of kilometers apart. As the number of PCs on a collision domain increases, so does the number of collisions. A network interface may be associated with a physical device, or it may be a representation of a virtual interface.
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