by Dinesh Thakur Category: Communication Networks

Coaxial cables are the guided media that carnes the signal of higher frequency range compared to twisted pair cable. Coaxial cables are also called coax. (short form). Two types of coaxial cables are widely used: 50 ohm cable and 75 ohm cable. 50 ohm cable is used for digital transmission and 75 ohm cable is used for analog transmission. Due to the shield provided, this cable has excellent noise immunity. It has a large bandwidth and low losses. Co-axial cables are easy to install. They are often installed either in a device to device daisy chain (Ethernet) or a star (ARC net).

 
by Dinesh Thakur Category: Communication Networks

Cyclic Redundancy Check (CRC) An error detection mechanism in which a special number is appended to a block of data in order to detect any changes introduced during storage (or transmission). The CRe is recalculated on retrieval (or reception) and compared to the value originally transmitted, which can reveal certain types of error. For example, a single corrupted bit in the data results in a one-bit change in the calculated CRC, but multiple corrupt bits may cancel each other out.

 
by Dinesh Thakur Category: Communication Networks

• In sliding window method, multiple frames are sent by sender at a time before needing an acknowledgment.

• Multiple frames sent by source are acknowledged by receiver using a single ACK frame.

 
by Dinesh Thakur Category: Communication Networks

Hubs/Repeaters are used to connect together two or more network segments of any media type. In larger design, signal quality begins to deteriorate as segment exceeds their maximum length. A hub provides the signal amplification required to allow a segment to be extended a greater distance.

 
by Dinesh Thakur Category: Communication Networks

Hamming code is technique developed by R.W. Hamming for error correction. This method corrects the error by finding the state at which the error has occurred.

 
by Dinesh Thakur Category: Communication Networks

• Bluetooth is, with the infrared, one of the major wireless technologies developed to achieve WPAN. Bluetooth is a wireless LAN technology used to connect devices of different functions such as telephones, computers (laptop or desktop), notebooks, cameras, printers and so on.

• Bluetooth project was started by SIG (Special Interest Group) formed by four companies  IBM, Intel, Nokia and Toshiba for interconnecting computing and communicating devices using short-range, lower-power, inexpensive wireless radios.



 
by Dinesh Thakur Category: Communication Networks

• In this method of flow control, the sender sends a single frame to receiver & waits for an acknowledgment.

• The next frame is sent by sender only when acknowledgment of previous frame is received.

 
by Dinesh Thakur Category: Communication Networks

• In all practical situations, the transmission of data needs to be bi-directional. This is called as full-duplex transmission.

• We can achieve this full duplex transmission i.e. by having two separate channels-one for forward data transfer and the other for separate transfer i.e. for acknowledgements.

 
by Dinesh Thakur Category: Communication Networks

IEEE 802.5 Token Ring: Token ring is the IEEE 802.5 standard for a token-passing ring in Communication networks. A ring consists of a collection of ring interfaces connected by point-to-point lines i.e. ring interface of one station is connected to the ring interfaces of its left station as well as right station. Internally, signals travel around the Communication network from one station to the next in a ring.

 
by Dinesh Thakur Category: Communication Networks

Data link layer is the second layer in OSI reference model and lies above the physical layer. The data link layer performs the following functions.

1. Data link layer receives the data from the network layer & divide it into manageable units called frames.

 
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.



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