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

When an electrical signal travels along a medium it gets attenuated depending upon the medium characteristics. That is why a LAN cannot send signal beyond a certain limit imposed by the different types of LAN technologies. To increase the length of the LAN, repeaters are frequently used. Repeaters in its simplest form relay analog electric signal. It means that they transmit the physical layer signals or data and therefore correspond to the bottom layer of OSI model.                        

 
by Dinesh Thakur Category: Communication Networks

100VG-AnyLan (VG =Voice Grade) is a joint development of AT&T Microelectronics, Hewlett-Packard, and IBM and is standardized by the newly created IEEE 802.12 committee. 100VG-AnyLAN supports Ethernet, Token Ring, and other LAN standards, incorporating a collision less polling technique. It is not that simple as it appears. A router upgrade is required to connect 100VG Ethernet and 100VG Token Ring.

 
by Dinesh Thakur Category: Communication Networks

With the advancement of time and intensive use of LAN, more workstations and more active users have resulted in more LAN traffic. Increased use of graphics and other bandwidth-intensive applications have increased LAN traffic. Other applications like video conferencing and multimedia have created a demand for fast LANs. Bandwidth of 10 Mbps, 16 Mbps and even 20 Mbps are becoming bottleneck. In response to this, Fast LANs have been developed, offering bandwidth of 100 Mbps and soon to 1 Gbps. Fast LAN options currently include:

 
by Dinesh Thakur Category: Communication Networks

Wireless LANs offer the obvious advantage of avoidance of cabling costs, which can be especially important in a dynamic environment where there is frequent reconfiguration of the workplace. Additionally, wireless LANs provides LAN capabilities in temporary quarters where costly cabling would have to be abandoned. Each workstation is fitted with a low power radio antenna.

 
by Dinesh Thakur Category: Communication Networks

Due its outstanding performance characteristics, fiber-optic cable is also used in LAN s. FDD I (Fiber Distributed Data Interface) is the current LAN standard (IEEE and ANSI) for such a network. FDDI can be extended to the desktop, either directly or through the use of twisted pair in a CDDI application.

 
by Dinesh Thakur Category: Communication Networks

The maximum allowable length of a segment for the 10Base5 is 500 meters. Up to 100 nodes can be connected to a segment. That is up to 100 transceivers can be connected. Repeaters are used to connect terminals that are separated from one another beyond the distance specified above, or to connect more than a limited number of nodes. Each repeater has two ports so that it receives signals through one of these ports and sends them through the other port after amplification. An example of the 10Base5 LAN, Up to 1024 nodes can be connected to a LAN expanded by using repeaters.

 
by Dinesh Thakur Category: Communication Networks

CDDI is also known as TPDDI (Twisted-pair Distributed Data Interface). CDDI employs Cat 5 UTP as an inexpensive means of connecting workstations and peripherals to FDDI fiber optic backbone LANs. A transmission rates up to 100 Mbps may be achieved in this scheme.

 
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

A pair of wires twisted together form a twisted pair. They have more noise immunity than the two-wire open lines. Each wire is insulated and has thickness in the order of 0.016 inches to 0.015 inches.

 
by Dinesh Thakur Category: Communication Networks

The Figure shows the BNC connector and T-connector. The BNC connector and T-connector, these are simple connectors that cannot exchange data. An NIC and T-connector must be directly connected.

 
by Dinesh Thakur Category: Communication Networks

This is also known as 10Base2, uses coaxial of thinner gauge of5 mm in diameter and bus topology as in the case of 10Base5 so that multiple computers can be connected to a single transmission line. Primarily it was used in office environments. The thinner cable is less costly to acquire and deploy, although its performance is less in terms of transmission distance. Because of its cost it is sometimes called as cheapnet. 10Base2 signifies in the same manner as 10Bases5except 2 is signified here as 200 meters maximum segment length (actually 185 meters).

 
by Dinesh Thakur Category: Communication Networks

The transceiver exchanges data signals handled by the NIC and electric signals sent over a transmission line. A I5-pin D-SUB connector is used to connect transceivers and transceiver cables. Multiport transceiver supports more than one NIC.

 
by Dinesh Thakur Category: Communication Networks

This uses traditional thick baseband coaxial cable in bus topology to connect multiple computers as shown. This single transmission line is called a segment. A coaxial cable 10mm in diameter, known as a thick coaxial cable is used as a transmission line. A terminator is connected at each end of the cable. Note that proper data communication cannot be assured even if one of these terminators is missing or not properly connected.

 
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

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

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

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

Data transmission can be divided into parallel and serial data transmission.

 
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.

 

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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.