by Dinesh Thakur Category: Communication Networks

Unbound transmission media extend beyond the limiting confines of cabling. They provide an excellent Communication Networks alternative for WANS. The lack of physical restrictions provides larger bandwidth as well as wide area capabilities. Unbound media typically operate at very high frequencies. The three types of unbound transmission media are: Radio wave, Micro wave, Infrared.



 
by Dinesh Thakur Category: Communication Networks

Data is transmitted between communication devices in multiples of fixed-length units, typically 8-bits. For example, if the computer is transferring a source program, the data will be made up of a block of 8-bit binary-encoded characters. On the other hand, if the data is in the form of a compiled object code of the program, the data will be made up of a block of 8-bit bytes. At the receiving end, the following parameters are determined to decode and interpret the message correctly.



 
by Dinesh Thakur Category: Communication Networks

Definition: Ethernet (pronounced "eether net") is a computer network technology which is used in different area networks like LAN, MAN, WAN. Ethernet connecting computers together with cable so the computers can share information. Within each main branch of the network, "Ethernet" can connect up to 1,024 personal computers and workstations.



 
by Dinesh Thakur Category: Communication Networks

This may be considered as the breakthrough for many of current ideas, algorithms and Internet technologies. It started Paul Baran in 1960s funded by Advanced Research Projects Agency (ARPA), an organization of the united States Defense Department and, therefore, named as Advanced Research Projects Agency Network (ARPANET) predecessor of the modern Internet. It was world's first fully operational packet switching computer network and the world's first successful computer network to implement the TCP/IP reference model that was used earlier by ARPANET, before being used in the Internet. The ARPANET is the first network that planed the seed of interent.



 
by Dinesh Thakur Category: Communication Networks

It is required that information must be encoded into signals before it can be transported across communication media. In more precise words we may say that the waveform pattern of voltage or current used to represent the 1s and 0s of a digital signal on a transmission link is called digital to digital line encoding. There are different encoding schemes available:



 
by Dinesh Thakur Category: Communication Networks

Radio waves, also called radio waves as they were discovered by German physicist Heinrich Hertz in 1888, are electromagnetic waves, that is to say the combined oscillation of an electric field and a magnetic field. Radio waves, infrared, visible light, ultraviolet, X-rays or gamma rays are all examples of electromagnetic waves.

 
by Dinesh Thakur Category: Communication Networks

The purpose of error control is to ensure that the information received by the receiver is exactly the information transmitted by the sender. As the communication channel is highly unreliable, the receiver must be able to deal with the received data, if it contains error. The term error control is defined as the process of identification or correction of error occurred in the transmitted data. There are two types of error control mechanisms. They are:



 
by Dinesh Thakur Category: Communication Networks

Broadband A communications medium that can carry a wide range of signal frequencies, typically from audio up to video frequencies. In telecommunications the significance of a broadband system is that it can carry television and videoconferencing data as well as voice calls. A broadband medium can be made to carry many signals at once by apportioning its total bandwidth into many independent channels, each of which carries only a specific range of frequencies. In contrast, a BASEBAND can carry only a single channel. ATM, ADSL and Cable TV are all broadband media, while standard ISDN barely qualifies.

 
by Dinesh Thakur Category: Communication Networks

Routers are used to connect both similar and dissimilar LANs. Router operates on the network layer of OSI model using the physical layer, data link layer and network layer to provide connectivity, addressing and switching. These are highly intelligent devices. In case of TCP/IP network, Internet Protocol (IP) is used as addresses for network; this is the router which interprets the IP address and delivers the packet reliably.

 
by Dinesh Thakur Category: Communication Networks

What is Hub: Another name of Hub is Ethernet Hub, Repeater Hub, Active Hub and Network Hub. Basically, it is a similar to switch but are not as "smart", 

Hub Definition and Meaning

hub in computer network is used for connecting multiple computers or segments of a LAN. Normally, it is used for Peer to Peer small Home Network. LAN Hub receive data packets (frames) through one port and broadcasts them through all other ports, so that all other computers or other network devices can see all packets.



 
by Dinesh Thakur Category: Communication Networks

The notion of quality of service, or QoS, concerns certain characteristics of a network connection under the sole of the network service provider liability.

A QoS value applies to the whole of a network connection. It must be identical at both ends of the connection, even if it is supported by several interconnected subnetworks each offering different services.

 
by Dinesh Thakur Category: Communication Networks

Gigabit Ethernet or GbE, is the penultimate evolution of Ethernet standard. Several improvements have been made for it to Fast Ethernet at 100 Mbit/s.

The new interface is called modified GMII (Gigabit Media Independent Interface). It includes a data path 8 bits, instead of 4 in the less powerful version. The transceivers operate with a clock operating at 125 MHz.

 
by Dinesh Thakur Category: Communication Networks

The most and latest wireless communication use electromagnetic airwaves either infrared or radio frequency to communicate information from one point wireless communication networks to another wireless communication networks Point. Without relaying on a physical connection. Radio waves are often referred to as radio carriers because they simply perform the function of delivering energy to a remote receiver.



 
by Dinesh Thakur Category: Communication Networks

Definition: Media access control (MAC) and logical link control (LLC) are the sublayers of the data link layer (Layer 2) in OSI Reference Model. 'MAC' is also refer to as MAC layer. It use MAC protocols to provides unique addressing identification and channel access control mechanism for network nodes to communicate with other nodes across a shared channel.



 
by Dinesh Thakur Category: Communication Networks

Fast Ethernet is the name of the extension to 100 Mbit/s Ethernet network to 10 Mbit/s. This is the IEEE 802.3u working group that is at the origin. Access technique is the same as in the Ethernet Version 10 Mbit/s, but at a speed multiplied by 10. transported frames are identical. This increase in speed may conflict with the wiring system and the possibility or not there such important transit flows.

 
by Dinesh Thakur Category: Communication Networks

Like repeaters, bridges are used to connect similar LANs together, for example, Ethernet-to-Ethernet and operate at the bottom two layers of the OSI model, i.e. physical layer and data link layer. As it operates on second layer of the OSI model,' it relays only necessary data to other signals. MAC addresses (physical addresses) are used to determine whether data is necessary or not.

 
by Dinesh Thakur Category: Communication Networks

Satellite radio, quite simply, is a non-terrestrial microwave transmission system utilizing a space relay station. Satellites have proved invaluable in extending the reach of voice, data, and video communications around the globe and into the most remote regions of the world. Exotic applications such as the Global Positioning System (GPS) would have been unthinkable without the benefit of satellites.

 
by Dinesh Thakur Category: Communication Networks

In case of coaxial cables and twisted cable the maximum signal frequency, and hence the information rate that can be transmitted using a solid conductor is limited. Optical fiber differs from both these transmission media in that it carries the transmitted information in the' form of a fluctuating beam of light in a glass fiber rather than as an electrical signal on a wire. This type of transmission has become strong support for digital network owing to its high capacity and other factors favorable for digital communication.



 
by Dinesh Thakur Category: Communication Networks

Infrared light transmissions have existed for many years and their use having been limited to TV remote controls and wireless slide projector remote controls. However, they now are assuming a position of some, if still limited, importance. Infrared systems use the infrared light spectrum to send a focused light beam to a receiver, much, as would a microwave system, although no reflective dish is used. Rather, pair of lenses is used, with a focused lens employed in the transmitting device and a collective lens in the receiving device as shown in Figure. Infrared is an airwave, rather that a conducted transmission system. Although generally used in short-haul transmission, they do offer substantial bandwidth, but with risks of interference.

 
by Dinesh Thakur Category: Communication Networks

Generally, some people use the term "Ethernet" or ether refers to cable. Ethernet was the original product designed by Xerox PARC based on Bob Metcalfe's idea. It was later upgraded to 10 Mbps by Xerox, Intel and DEC.

 

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About Dinesh Thakur

Dinesh ThakurDinesh Thakur holds an B.SC (Computer Science), MCSE, MCDBA, CCNA, CCNP, A+, SCJP certifications. Dinesh authors the hugely popular blog. Where he writes how-to guides around Computer fundamental , computer software, Computer programming, and web apps. For any type of query or something that you think is missing, please feel free to Contact us.