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Showing posts with label Network Devices. Show all posts
Showing posts with label Network Devices. Show all posts

What is a Router and how it works


What is a Router and how it works

Router, which facilitates the transfer of data in the form of packets, is a device connecting two or more networks. Routers can be used to send the data either within the same network or to different networks.

The data packets which are sent over a network are directed on basis of their address. Each packet contains a header which can be used to determine the destination address and the source.

When the packet is sent over the network it is transferred from one network to other. When internet is installed in homes, a router routes the information that is received through your broadband Internet via modem, then decodes it and finally delivers it to your desktop.

When the packet arrives at the router, information contained in its header is scrutinized and based on this scrutiny the packet is forwarded to its destination. Routers also use protocols like ICMP (Internet Message control Protocol) to exchange information and try to figure out best possible route for information packet transfer in terms of cost and time.

Routers can even be used at home if a user wants to connect more than one computer with a single network (Internet connection).

Types of Router:

  • Cable Router – Cable routers are commonly used where a user has subscribed to high-speed cable Internet. While the modem is plugged into the wall socket from which the user also receives the cable TV signal, cable router is connected to the modem, which sends the signal to home computers.
  • Wireless Router – A wireless router can be used to connect to Internet or a personal network. Nowadays many companies manufacturing router provide it with built in devices thus eliminating the needs for extra devices. Routers which use the Wi-Fi methodology also connect with other wireless devices like NIC (Network Interface cards) and wireless repeaters.
  • Multicast Router – Multicast routers are brought to use when it is desired that multiple users should receive a single data packet. Depending upon number of users and the bandwidth available, multicast routers, either uses dense mode routing or sparse mode routing. Both the networks make use of multicast datagram’s which are sent to the routers and hence include a larger number of receivers over sources.

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Modem


Modem

Introduction
Modem is short for modulator-demodulator. Modems are required so that various computers can communicate with each other over a network. They convert the analog signals, which a computer receives over a telephone or cable television line into the digital signals.

When the use of Modem began in 1970’s most of them were used to connect computers to a Bulletin Board Systems (BBS). Initially 300 BAUD Modems were used which could transmit 30 characters per second. But nowadays modems available in the market transfer the data at a much faster rate thus allowing you to download huge amounts within few minutes

Types of Modem

  • Dial-up Modems- These modems were widely used in the late 1990’s. Dial-up modems used standard telephone line to connect to the Internet Service Provider (ISP). When developed these modems had the data transfer capability of 56 Kbps but the major drawback of using the dial-up technology was that a user couldn’t use telephone line while using the Internet.
  • Cable Modems – These types of modems allow computer systems and networks to communicate over the cable television infrastructure networks. These networks use co-axial cable media to communicate. Cable modems are generally used for broadband based Internet access.
  • Wireless Modems – Wireless modem is a network device which connects to wireless network. It attaches directly to your notebook or a computer. Wireless modem interfaces include Compact Flash, USB and Serial Port.
  • Voice Modems- Voice modems are just like standard modems that are capable of recording or playing audio over the telephone line. They are used for telephony applications.
  • ADSL/DSL Modems – ADSL stands for Asymmetric Digital subscriber line. However unlike dial up one can receive and make phone calls while simultaneously using the Internet. The reason why this is termed as asymmetric is because while using the ADSL modems user has much higher download speeds as compared to the upload speed.
On the other hand DSL (Digital Subscriber Line) modems give equal speed while both downloading and uploading the content on the Internet.

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What is Ethernet


What is Ethernet

Ethernet is a computer networking technology primarily used for Local Area Network (LAN). It was invented by Robert Metcalfe in 1970’s while he worked at Xerox.

In LAN architecture you have, two or more computers connected with each other and sharing resources such as Internet, fax, scanners etc. Each computer or a workstation has a NIC (Network Interface card). This NIC is connected to Ethernet cable which in turn is connected to the central hub or a Local server, which directs all the communication processes and enables sharing of resources.

Initially Ethernet used twisted pair or co-axial cables to connect to the Internet or a network. CSMA/CD (carrier Sense Multiple Access/ Collision Detection) technology was used to transmit the data and it employed the use of co-axial cable for this transmission. But nowadays Ethernet uses full duplex transmission via twisted copper cables or fiber optical cables.

Ethernet is the most popular LAN protocol and has evolved over the period of time. When invented its data transmission capability was few Mbps like 10 Mbps but now we have Ethernet cables with data transmission capability of over 1000Mbps or it is called as Gigabit Ethernet. In fact Ethernet cables with capability of 10Gbps have now been introduced. The length of the cable used may vary depending upon the usage. It may be few meters in length or might spread over entire school and universities campuses.

The formal standardization of Ethernet by IEEE (Institute of Electrical and Electronics Engineers) is known as IEEE 802.3

Ethernet Cable

Though we have been seeing increase in wireless network platform but still Ethernet is a faster, reliable and secure source of internet connectivity.

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