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.
You can actually network two PCs together in this way.
Networking Basics: Part 1 - Networking Hardware
You can create what is known as a cross over cable. A cross over cable is simply a network cable that has the sending and receiving wires reversed at one end, so that two PCs can be linked directly together. The problem with using a cross over cable to build a network is that the network will be limited to using no more and no less than two PCs. Rather than using a cross over cable, most networks use normal Ethernet cables that do not have the sending and receiving wires reversed at one end.
Of course the sending and receiving wires have to be reversed at some point in order for communications to succeed. This is the job of a hub or a switch.
Hubs are starting to become extinct, but I want to talk about them any way because it will make it easier to explain switches later on. There are different types of hubs, but generally speaking a hub is nothing more than a box with a bunch of RJ ports.
Each computer on a network would be connected to a hub via an Ethernet cable. You can see a picture of a hub, shown in Figure C. Figure C: A hub is a device that acts as a central connection point for computers on a network. A hub has two different jobs. Its first job is to provide a central point of connection for all of the computers on the network. Every computer plugs into the hub multiple hubs can be daisy chained together if necessary in order to accommodate more computers.
Right now you might be wondering how data gets to the correct destination if more than two PCs are connected to a hub. The secret lies in the network card. When a computer on an Ethernet network transmits data across an Ethernet network containing PCs connected to a hub, the data is actually sent to every computer on the network.
As each computer receives the data, it compares the destination address to its own MAC address. If the addresses match then the computer knows that it is the intended recipient, otherwise it ignores the data. As you can see, when computers are connected via a hub, every packet gets sent to every computer on the network.
The problem is that any computer can send a transmission at any given time. Have you ever been on a conference call and accidentally started to talk at the same time as someone else? This is the same thing that happens on this type of network. When a PC needs to transmit data, it checks to make sure that no other computers are sending data at the moment. If the line is clear, it transmits the necessary data.
If another computer tries to communicate at the same time though, then the packets of data that are traveling across the wire collide and are destroyed this is why this type of network is sometimes referred to as a collision domain.
Both PCs then have to wait for a random amount of time and attempt to retransmit the packet that was destroyed. As the number of PCs on a collision domain increases, so does the number of collisions. As the number of collisions increase, network efficiency is decreased.
This is why switches have almost completely replaced hubs. A switch, such as the one shown in Figure D, performs all of the same basic tasks as a hub. The difference is that when a PC on the network needs to communicate with another PC, the switch uses a set of internal logic circuits to establish a dedicated, logical path between the two PCs.
What this means is that the two PCs are free to communicate with each other, without having to worry about collisions. Figure D: A switch looks a lot like a hub, but performs very differently. Yes, they eliminate collisions, but there is more to it than that.
Because of the way that switches work, they can establish parallel communications paths. In a collision domain, these types of parallel communications would be impossible because they would result in collisions.
In this article, I have discussed some of the basic components that make up a simple network. In Part 2, I will continue the discussion of basic networking hardware. Part 1 - Networking Hardware.
Brien Posey is a freelance technology author and speaker with over two decades of IT experience. Prior to going freelance, Brien was a CIO for a national chain of hospitals and healthcare facilities. In addition, Brien has worked as a network administrator for some of the largest insurance companies in America.
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Over 1,, fellow IT Pros are already on-board, don't be left out! 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.
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.
Networking Basics: Part 1 - Networking Hardware
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.
Media Access Control Media access control is a communications protocol that is used to distinguish specific devices. Each device is supposed to get a unique MAC address during the manufacturing process that differentiates it from every other device on the internet.
Addressing hardware by the MAC address allows you to reference a device by a unique value even when the software on top may change the name for that specific device during operation. Media access control is one of the only protocols from the link layer that you are likely to interact with on a regular basis.
IP The IP protocol is one of the fundamental protocols that allow the internet to work.
IP addresses are unique on each network and they allow machines to address each other across a network. Networks can be linked together, but traffic must be routed when crossing network boundaries. This protocol assumes an unreliable network and multiple paths to the same destination that it can dynamically change between. There are a number of different implementations of the protocol. The most common implementation today is IPv4, although IPv6 is growing in popularity as an alternative due to the scarcity of IPv4 addresses available and improvements in the protocols capabilities.
It is used to send messages between devices to indicate the availability or error conditions. These packets are used in a variety of network diagnostic tools, such as ping and traceroute. Usually ICMP packets are transmitted when a packet of a different kind meets some kind of a problem. Basically, they are used as a feedback mechanism for network communications. TCP is one of the protocols that encapsulates data into packets.
Hubs and Switches
It then transfers these to the remote end of the connection using the methods available on the lower layers. On the other end, it can check for errors, request certain pieces to be resent, and reassemble the information into one logical piece to send to the application layer.
The protocol builds up a connection prior to data transfer using a system called a three-way handshake. This is a way for the two ends of the communication to acknowledge the request and agree upon a method of ensuring data reliability. After the data has been sent, the connection is torn down using a similar four-way handshake.
It is safe to say that the internet we know today would not be here without TCP. It is a popular companion protocol to TCP and is also implemented in the transport layer.
It does not verify that data has been received on the other end of the connection. This might sound like a bad thing, and for many purposes, it is.A CPU has 3 components as listed below. This limitation can be overcome by using repeaters and switches. Files servers. The carriage holding the pens should provide all motions. Figure A: This is what an Ethernet card looks like Modern Ethernet networks use twisted pair cabling containing eight wires.
Switches normally have numerous ports, facilitating a star topology for devices, and cascading additional switches. This might sound like a bad thing, and for many purposes, it is. Inside the PC 4 4 5.
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