Wednesday, October 17, 2018

What are the types of cable?

WHAT ARE THE TYPES OF CABLE?
A.Twisted pair



The use of two wires twisted together helps to reduce crosstalk and electromagnetic induction. While twisted-pair cable is used by older telephone networks and is the least expensive type of local-area network (LAN)cable, most networks contain some twisted-pair cabling at some point along the network.
Shielded Twisted Pair
            
   The extra covering in shielded twisted pair wiring protects the transmission line from electromagnetic interference leaking into or out of the cableSTP cabling often is used in Ethernet networks, especially fast data rate Ethernets. Contrast with UTP.


     Unshielded Twisted Pair
                      

UTP cable is a 100 ohm copper cable that consists of 2 to 1800 unshielded twisted pairs surrounded by an outer jacket. They have no metallic shield. This makes the cable small in diameter but unprotected against electrical interference. The twist helps to improve its immunity to electrical noise and EMI.

B. Coaxial

Coaxial cable is a type of copper cable specially built with a metal shield and other components engineered to block signal interference. It is primarily used by cable TV companies to connect their satellite antenna facilities to customer homes and businesses.

C.Fiber Optic



Fiber optics, or optical fiber, refers to the medium and the technology associated with the transmission of information as light pulses along a glass or plastic strand or fiber.


Straight Through and Crossover Cable


A straight through cable is a type of twisted pair cable that is used in local area networks to connect a computer to a network hub such as a router. This type of cable is also sometimes called a patch cable and is an alternative to wireless connections where one or more computers access a router through a wireless signal. On a straight through cable, the wired pins match. Straight through cable use one wiring standard: both ends use T568A wiring standard or both ends use T568B wiring standard. The following figure shows a straight through cable of which both ends are wired as the T568B standard.
An Ethernet crossover cable is a type of Ethernet cable used to connect computing devices together directly. Unlike straight through cable, crossover cables use two different wiring standards: one end uses the T568A wiring standard, and the other end uses the T568B wiring standard. The internal wiring of Ethernet crossover cables reverses the transmit and receive signals. It is most often used to connect two devices of the same type: e.g. two computers (via network interface controller) or two switches to each other.

Source: Google










































   


































Monday, August 27, 2018

What are the types of topology?

What are the types of topology? 
                 Star Topology



        






                              
 Star network is one of the most common computer network topologies. In its simplest form, a star network consists of one central hub which acts as a conduit to transmit messages. In star topology, every host is connected to a central hub.https://en.wikipedia.org/wiki/Star_network

                      

                   Ring Topology


                        






                              
ring network is a network topology in which each node connects to exactly two other nodes, forming a single continuous pathway for signals through each node - a ring. Data travels from node to node, with each node along the way handling every packet.https://en.wikipedia.org/wiki/Ring_netwok

                     Mesh Topology












                              
mesh network (or simply Meshnet) is a local network topology in which the infrastructure nodes  bridges, switches and other infrastructure devices) connect directly, dynamically and non-hierarchically to as many other nodes as possible and cooperate with one another to efficiently route data from/to clients. https://en.wikipedia.org/wiki/Mesh_networking

                Linear Bus Topology




Linear Bus A li 

                                                                             Linear bus topology is a type of network topologyin which each device is connected one after the other in a sequential chain (shown right). In this case, the bus is the network connection between the devices, and if any link in the network chain is severed, all network transmission is halted. It works well for small networks because it is simple to set up and utilizes shorter cables since each device is connected to the next. It is a poor solution for larger networks, however since the entire network relies on each connection, and network speed is reduced as more devices are added.https://www.computerhope.com › Dictionary › L - Definitions
                   
                   Hybrid Topology             

Hybrid topology is an integration of two or more different topologies to form a resultant topology which has many advantages (as well as disadvantages) of all the constituent basic topologies rather than having characteristics of one specific topology.
https://blossoms.mit.edu/sites/default/files/video/.../Notes-on-Hybrid-topology.pd


Source: Google





ogy consists of a main run of cable with a terminator at each end All nodes (file server, workstations, and peripherals) are connected to the linear cable. 
Linear Bus A linear bus topology consists of a main run of cable with a terminator at each end All nodes (file server, workstations, and peripherals) are connected to the linear cable. 
                    
































Wednesday, August 22, 2018

What are the types of computer network?

What are the types of computer network?

First, What is a Computer Network?

A computer network is a set of computers connected together for the purpose of sharing resources. The most common resource shared today is connection to the Internet. Other shared resources can include a printer or a file server. The Internet itself can be considered a computer network.(source: https://study.com/academy/lesson/what-is-a-computer-network-types-definition-quiz.html)


4 Types of Computer Network 


Personal Area Network (PAN)
-is a computer network used for data transmission amongst devices such as computers, telephones, printers, etc. 
  • it is also the interconnection of information technology devices within the range of an individual person, typically within a range of 10 meters. For example, a person traveling with a laptop, a personal digital assistant (PDA), and a portable printer could interconnect them without having to plug anything in, using some form of wireless technology. Typically, this kind of personal area network could also be interconnected without wires to the Internet or other networks. Also see wireless personal area network (WPAN) which is virtually a synonym since almost any personal area network would need to function wirelessly. Conceptually, the difference between a PAN and a wireless LAN is that the former tends to be centered around one person while the latter is a local area network (LAN) that is connected without wires and serving multiple users.

  •  In another usage, a personal area network (PAN) is a technology that could enable wearable computer devices to communicate with other nearby computers and exchange digital information using the electrical conductivity of the human body as a data network. For example, two people each wearing business card-size transmitters and receivers conceivably could exchange information by shaking hands. The transference of data through in

    tra-body contact, such as handshakes, is known as linkup. The human body's natural salinity makes it a good conductor of electricity. An electric field passes tiny currents, known as Pico amps, through the body when the two people shake hands. The handshake completes an electric circuit and each person's data, such as e-mail addresses and phone numbers, are transferred to the other person's 
    laptop computer or a similar device. A person's clothing also could act as a mechanism for transferring this data. (source:https://searchmobilecomputing.techtarget.com/definition/personal-area-network






Local Area Network (LAN)
- is a computer network that spans a relatively small area.
  • Stands for "Local Area Network" and is pronounced "lan." A LAN is a network of connected devices that exist within a specific location. LANs may be found in homes, offices, educational institution, or other areas.
    A LAN may be wiredwireless, or a combination of the two. A standard wired LAN uses Ethernet to connect devices together. Wireless LANs are typically created using a Wi-Fi signal. If a router supports both Ethernet and Wi-Fi connections, it can be used to create a LAN with both wired and wireless devices.
 Types of LANs
Most residential LANs use a single router to create the network and manage all the connected devices. The router acts as the central connection point and enables devices, such as computers, tablets, and smartphones to communicate with each other. Typically, the router is connected to a cable or DSL modem, which provides Internet access to connected devices.
computer may also be the central access point of a LAN. In this setup, the computer acts as a server, providing connected machines with access to files and programs located on the server. It also includes LAN software used to manage the network and connected devices. LAN servers are more common in business and educational networks, since the extra capabilities are not required by most home users. In a server-based LAN, devices may connect directly to the server or indirectly via a router or switch.(source: https://techterms.com/definition/lan)





Metropolitan Area Network (MAN)
- it involves connecting several networks together that reside with a city, town or metropolis.

-A metropolitan area network (MAN) is similar to a local area network (LAN) but spans an entire city or campus. MANs are formed by connecting multiple LANs. Thus, MANs are larger than LANs but smaller than wide area networks (WAN). 

-MANs are extremely efficient and provide fast communication via high-speed carriers, such as fiber optic cables.

-A MAN is ideal for many kinds of network users because it is a medium-size network. MANs are used to build networks with high data connection speeds for cities and towns. 


-The working mechanism of a MAN is similar to an Internet Service Provider (ISP), but a MAN is not owned by a single organization. Like a WAN, a MAN provides shared network connections to its users. A MAN mostly works on the data link layer, which is Layer 2 of the Open Systems Interconnection (OSI) model. 

Distributed Queue Dual Bus (DQDB) is the MAN standard specified by the Institute Of Electrical And Electronics Engineers (IEEE) as IEEE 802.6. Using this standard, a MAN extends up to 30-40 km, or 20-25 miles. (source: 
https://www.techopedia.com/definition/8238/metropolitan-area-network-man)





Wide Area Network (WAN)
-is a geographically distributed private telecommunications network that interconnects multiple area network.

-A WAN (wide area network) is a communications network that spans a large geographic area such as across cities, states, or countries. They can be private to connect parts of a business or they can be more public to connect smaller networks together.
The easiest way to understand what a WAN is to think of the internet as a whole, which is the world's largest WAN. The internet is a WAN because, through the use of ISPs, it connects lots of smaller local area networks (LANs) or metro area networks (MANs).
On a smaller scale, a business may have a WAN that's comprised of cloud services, its headquarters, and smaller branch offices. The WAN, in this case, would be used to connect all of those sections of the business together.
No matter what the WAN joins together or how far apart the networks are, the end result is always intended to allow different smaller networks from different locations to communicate with one another.
-How WANs Are Connected
Since WANs, by definition, cover a larger distance than LANs, it makes sense to connect the various parts of the WAN using a virtual private network (VPN). This provides protected communications between sites, which is necessary given that the data transfers are happening over the internet.
Although VPNs provide reasonable levels of security for business uses, a public internet connection does not always provide the predictable levels of performance that a dedicated WAN link can. This is why fiber optic cables are sometimes used to facilitate communication between the WAN links.(source: https://www.lifewire.com/wide-area-network-816383)


                           

















  • Internet was invented by Tim Berners-Lee in 1989.

    • Interestingly, Microsoft is ahead of Google in terms of number of servers owned. Microsoft has over one million servers whereas Google has 900,000.
    • According to Google, Internet contains 5 million Terabytes of data. Google’s search index is about 0.004% of this.
    • Now about 3 billion people are connected to Internet. World’s total population is about 7 billion.
    • QWERTY keyboard sequence is 129 years old.
    • First ever microprocessor by Intel was “4004”
    • First Computer Company to register domain name was “Digital Equipment Corporation”
    • Micral N was the first personal computer built on Intel processor 8008. This personal computer was built in 1972 and more than 90,000 units were sold
    • Six main Internet cable landing stations are located in Tokyo, Singapore, New York, Cornwell, Southern Florida and Hong Kong.
    • In 2008, Internet was controlled by 30 million servers. Now this number is nearly 75 million.
    Source: Google












    Wednesday, August 1, 2018

    How to be responsible netizen?


     
    How to be responsible netizen?                               To become a reponsible netizen you must be engaged with your country specially being careful using social media like Facebook, Twitter or Instagram, because the most influential stranger now a days is the social media itself.


                                 To prevent it i think we must think before we share something in any sites. About how to be responsible netizen. First we should know what and who is netizen. A netizen is anyone and when I say anyone it means everyone could be a netizen.A netizen is someone who uses the internet for any reason.You are already a netizen by reading this blog. Last note about netizens, They are anyone who uses something online like Facebook ect.. in the internet including email. Now being a responsible digital citizen means you respect everyone using the internet.           
        
             
    It is time to go deeper into one of the NIOS campaign bullying topic, Cyberbullying. To cyberbullying someone does not only mean creating i hate you pages on facebook but also making a comment that might hurt others feelings. Cyberbullying happens to a lot of people so don t feel bad if you are one of them.


    Source: Google

























    Reformatting a Personal Computer

    Reformatting a Personal Computer 1. Start your PC and press key F2, F12 or delete key (Depends on your PC model).  ...