Knowledge Of Computer Hardware And Networking Concepts Pdf
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Computer network , two or more computers that are connected with one another for the purpose of communicating data electronically. Besides physically connecting computer and communication devices, a network system serves the important function of establishing a cohesive architecture that allows a variety of equipment types to transfer information in a near-seamless fashion.
- Computer network
- Networking Basics: What You Need To Know
- Introduction to Computer Networking and Hardware Concepts
A computer network is a group of two or more interconnected computer systems. You can establish a network connection using either cable or wireless media. Every network involves hardware and software that connects computers and tools.
A computer network is a group of computers that use a set of common communication protocols over digital interconnections for the purpose of sharing resources located on or provided by the network nodes. The interconnections between nodes are formed from a broad spectrum of telecommunication network technologies, based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topologies.
The nodes of a computer network may include personal computers , servers , networking hardware , or other specialised or general-purpose hosts. They are identified by hostnames and network addresses. Hostnames serve as memorable labels for the nodes, rarely changed after initial assignment. Network addresses serve for locating and identifying the nodes by communication protocols such as the Internet Protocol.
Computer networks may be classified by many criteria, for example, the transmission medium used to carry signals, bandwidth , communications protocols to organize network traffic, the network size, the topology, traffic control mechanism, and organizational intent.
Computer networks support many applications and services , such as access to the World Wide Web , digital video , digital audio , shared use of application and storage servers , printers, and fax machines , and use of email and instant messaging applications. Computer networking may be considered a branch of computer science , computer engineering , and telecommunications , since it relies on the theoretical and practical application of the related disciplines.
Computer networking was influenced by a wide array of technology developments and historical milestones. A computer network extends interpersonal communications by electronic means with various technologies, such as email , instant messaging , online chat , voice and video telephone calls , and video conferencing.
A network allows sharing of network and computing resources. Users may access and use resources provided by devices on the network, such as printing a document on a shared network printer or use of a shared storage device. A network allows sharing of files, data, and other types of information giving authorized users the ability to access information stored on other computers on the network. Distributed computing uses computing resources across a network to accomplish tasks.
Most modern computer networks use protocols based on packet-mode transmission. A network packet is a formatted unit of data carried by a packet-switched network. The physical link technologies of packet network typically limit the size of packets to a certain maximum transmission unit MTU. A longer message is fragmented before it is transferred and once the packets arrive, they are reassembled to construct the original message.
Packets consist of two types of data: control information and user data payload. The control information provides data the network needs to deliver the user data, for example, source and destination network addresses , error detection codes, and sequencing information. Typically, control information is found in packet headers and trailers , with payload data in between.
With packets, the bandwidth of the transmission medium can be better shared among users than if the network were circuit switched. When one user is not sending packets, the link can be filled with packets from other users, and so the cost can be shared, with relatively little interference, provided the link isn't overused.
Often the route a packet needs to take through a network is not immediately available. In that case, the packet is queued and waits until a link is free. Network topology is the layout, pattern, or organizational hierarchy of the interconnection of network hosts, in contrast to their physical or geographic location.
Typically, most diagrams describing networks are arranged by their topology. The network topology can affect throughput, but reliability is often more critical. In general, the more interconnections there are, the more robust the network is; but the more expensive it is to install. The physical layout of the nodes in a network may not necessarily reflect the network topology. As an example, with FDDI , the network topology is a ring, but the physical topology is often a star, because all neighboring connections can be routed via a central physical location.
Physical layout is not completely irrelevant, however, as common ducting and equipment locations can represent single points of failure due to issues like fires, power failures and flooding. An overlay network is a virtual network that is built on top of another network.
Nodes in the overlay network are connected by virtual or logical links. Each link corresponds to a path, perhaps through many physical links, in the underlying network. The topology of the overlay network may and often does differ from that of the underlying one. For example, many peer-to-peer networks are overlay networks. They are organized as nodes of a virtual system of links that run on top of the Internet. Overlay networks have been around since the invention of networking when computer systems were connected over telephone lines using modems , before any data network existed.
The most striking example of an overlay network is the Internet itself. The Internet itself was initially built as an overlay on the telephone network. Address resolution and routing are the means that allow mapping of a fully connected IP overlay network to its underlying network.
Another example of an overlay network is a distributed hash table , which maps keys to nodes in the network. In this case, the underlying network is an IP network, and the overlay network is a table actually a map indexed by keys.
Overlay networks have also been proposed as a way to improve Internet routing, such as through quality of service guarantees achieve higher-quality streaming media. Previous proposals such as IntServ , DiffServ , and IP Multicast have not seen wide acceptance largely because they require modification of all routers in the network.
The overlay network has no control over how packets are routed in the underlying network between two overlay nodes, but it can control, for example, the sequence of overlay nodes that a message traverses before it reaches its destination. For example, Akamai Technologies manages an overlay network that provides reliable, efficient content delivery a kind of multicast.
Academic research includes end system multicast,  resilient routing and quality of service studies, among others. The transmission media often referred to in the literature as the physical medium used to link devices to form a computer network include electrical cable , optical fiber , and free space. In the OSI model , the software to handle the media is defined at layers 1 and 2 — the physical layer and the data link layer.
A widely adopted family that uses copper and fiber media in local area network LAN technology are collectively known as Ethernet. The media and protocol standards that enable communication between networked devices over Ethernet are defined by IEEE Wireless LAN standards use radio waves , others use infrared signals as a transmission medium. Power line communication uses a building's power cabling to transmit data. Network connections can be established wirelessly using radio or other electromagnetic means of communication.
The last two cases have a large round-trip delay time , which gives slow two-way communication but doesn't prevent sending large amounts of information they can have high throughput. Apart from any physical transmission media, networks are built from 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 so may perform multiple functions. A network interface controller NIC is computer hardware that connects the computer to the network 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. 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 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. Repeaters work on the physical layer of the OSI model but still 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 used in a network, e.
An Ethernet repeater with multiple ports is known as an Ethernet hub. In addition to reconditioning and distributing network signals, a repeater hub assists with collision detection and fault isolation for the network. Hubs and repeaters in LANs have been largely obsoleted by modern network switches.
Network bridges and network switches are distinct from a hub in that they only forward frames to the ports involved in the communication whereas a hub forwards to all ports.
Switches normally have numerous ports, facilitating a star topology for devices, and for cascading additional switches. Bridges and switches operate at the data link layer layer 2 of the OSI model and bridge traffic between two or more network segments to form a single local network.
Both are devices that forward frames of data between ports based on the destination MAC address in each frame. If an unknown destination MAC is targeted, the device broadcasts the request to all ports except the source, and discovers the location from the reply.
Bridges and switches divide the network's collision domain but maintain a single broadcast domain. Network segmentation through bridging and switching helps break down a large, congested network into an aggregation of smaller, more efficient networks. A router is an internetworking device that forwards packets between networks by processing the addressing or routing information included in the packet.
The routing information is often processed in conjunction with the routing table. A router uses its routing table to determine where to forward packets and does not require broadcasting packets which is inefficient for very big networks. 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. Early modems modulated audio signals sent over a standard voice telephone line.
Modems are still commonly used for telephone lines, using a digital subscriber line technology and cable television systems using DOCSIS technology. A firewall is a network device or software for controlling network security and access rules. Firewalls are inserted in connections between secure internal networks and potentially insecure external networks such as the Internet.
Firewalls are typically configured to reject access requests from unrecognized sources while allowing actions from recognized ones. The vital role firewalls play in network security grows in parallel with the constant increase in cyber attacks. A communication protocol is a set of rules for exchanging information over a network. In a protocol stack also see the OSI model , the protocol is divided up into layers , where each protocol layer leverages the services of the protocol layer below it until the lowest layer controls the hardware that sends information across the media.
Today, the use of protocol layering is ubiquitous across the field of computer networking. This stack is used between the wireless router and the home user's personal computer when the user is surfing the web. Communication protocols have various characteristics.
Networking Basics: What You Need To Know
Computer hardware includes the physical parts of a computer , such as the case ,  central processing unit CPU , monitor , mouse , keyboard , computer data storage , graphics card , sound card , speakers and motherboard. By contrast, software is the set of instructions that can be stored and run by hardware. Hardware is so-termed because it is " hard " or rigid with respect to changes, whereas software is "soft" because it is easy to change. Hardware is typically directed by the software to execute any command or instruction. A combination of hardware and software forms a usable computing system, although other systems exist with only hardware. The template for all modern computers is the Von Neumann architecture , detailed in a paper by Hungarian mathematician John von Neumann.
Students' Understanding of Computer Networking Concepts .. 62 hardware skills in commerce and in industry worldwide, computer networking and hardware courses are loads/ctarchery.org Kolb, D. A.
Introduction to Computer Networking and Hardware Concepts
A network connects computers, mobile phones, peripherals, and even IoT devices. Switches, routers, and wireless access points are the essential networking basics. Through them, devices connected to your network can communicate with one another and with other networks, like the Internet.
Computer networks share common devices, functions, and features including servers, clients, transmission media, shared data, shared printers and other hardware and software resources, network interface card NIC , local operating system LOS , and the network operating system NOS. Servers - Servers are computers that hold shared files, programs, and the network operating system. Servers provide access to network resources to all the users of the network. There are many different kinds of servers, and one server can provide several functions. For example, there are file servers, print servers, mail servers, communication servers, database servers, fax servers and web servers, to name a few.
A computer network is a group of computers that use a set of common communication protocols over digital interconnections for the purpose of sharing resources located on or provided by the network nodes. The interconnections between nodes are formed from a broad spectrum of telecommunication network technologies, based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topologies. The nodes of a computer network may include personal computers , servers , networking hardware , or other specialised or general-purpose hosts. They are identified by hostnames and network addresses.
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