gtvc eu 5 org aiseries Computer Networking New

gtvc. eu 5. org aiseries

Computer Networking New Edition By Asif Iqbal gtvc. eu 5. org aiseries

LECTURE - 02 gtvc. eu 5. org aiseries

Computer Network (Elements) There are three elements of data-communication • Sender • Receiver • Channel Sender Channel Transmission Medium gtvc. eu 5. org Receiver aiseries

Computer Network (Elements) Sender A device used to send data. Receiver A device used to receive the message (data). Channel A medium over which the data is sent. gtvc. eu 5. org aiseries

Computer Network (Elements) gtvc. eu 5. org aiseries

transmission Mode (Types) 1. Simplex 2. Half Duplex 3. Full Duplex gtvc. eu 5. org aiseries

Simplex (Transmission) Sender Channel Transmission Medium gtvc. eu 5. org Receiver aiseries

Half-Duplex (Transmission) Sender Channel Transmission Medium gtvc. eu 5. org Receiver aiseries

Full-Duplex (Transmission) Channel Transmission Medium Sender A Receiver B gtvc. eu 5. org aiseries

Communication (Types) • • Parallel Serial gtvc. eu 5. org aiseries

Parallel (Transmission) • • Each bit is transmitted on separate transmission Channel (8, 16, 32, 64) The pathways between the CPU and memory are parallel, and they used to be parallel between the CPU and peripheral devices. Data transfer at very high speed Limitations • • Requires more complex electronics Almost Impossible multiple channels of same length Signals on multiple data lines can arrive on receiving ends at different times, which need synchronization. Susceptible to electromagnetic interference between the wires. gtvc. eu 5. org aiseries

Parallel (Transmission) gtvc. eu 5. org aiseries

Serial (Transmission) • • Each bit is transmit on single channel. At increasingly higher transfer rates, it is more efficient to build channels that carry data over a single wire rather than 32 or 64. It is therefore more efficient to design ever faster serial lines than to create and build the necessary circuitry to keep faster parallel channels properly synchronized. It is viewed as a reliable data transmission method because a data bit is only sent if the previous data bit has already been received. gtvc. eu 5. org aiseries

Serial Transmission (Classes) • • Synchronous Asynchronous gtvc. eu 5. org aiseries

Synchronous (Transmission) • • • Sends data in blocks called frames or packets in fix interval Sender and Receiver are synchronized Each block is sent in predefined fixed time interval Start and stop bit patterns are called Synchronous byte This method of transmission is used when large amounts of data need to be transferred quickly since data is transferred in large blocks instead of individual characters. The data blocks are spaced and grouped in regular intervals and preceded by synchronous characters. This method is complicated More expensive Data transfer quickly gtvc. eu 5. org aiseries

Asynchronous (Transmission) • • Asynchronous transmission is the transmission of data in which each character is a self-contained unit with its own start and stop bits and an uneven interval between them. Message is send one character at a time Uses start and stop bits to signify the beginning and ending bits The start and stop bits have opposite polarity. Start and stop bits tell the receiving devices that characters are coming and the characters has been sent. Receiving device uses parity bit to verify that the data was received correctly. This transmission is not used when great amount of data must be sent rapidly. Data is send whenever it is convenient for sender. gtvc. eu 5. org aiseries

Synchronous (Transmission) gtvc. eu 5. org aiseries

LECTURE - 02 (Summing Up) gtvc. eu 5. org aiseries