Category: Computer network

Selective repeat protocol

In previous article we studied about sliding window protocol. Selective repeat protocol is based on sliding window protocol. It is also called Selective Repeat ARQ (Automatic Repeat reQuest). Here, only the erroneous or lost frames are re-transmitted. Here, window size of sender and receiver are equal. Window size is half of maximum sequence number. If maximum sequence […]

A Protocol Using Go-Back-N

In previous article we have discussed about one bit sliding window protocol which is based on the concept of sliding window protocol.  In one bit sliding window protocol the window size is of 1 bit. But in Go-Back-N protocol, senders window size is of N and receivers window size is of 1. It is a data […]

One bit sliding window protocol

In previous article we have discussed about sliding window protocol. One bit sliding window protocol is based on the concept of sliding window protocol. But here the window size is of 1 bit. One bit sliding window protocol is used for delivery of data frames. Sender has sending window. Receiver has receiving window. Sending and receiving […]

Sliding Window Protocol

Sliding windows protocol works as follows: Sender sends a fixed number of frames without acknowledgments. Each frame is labelled with a sequence number. On getting acknowledgments from the receiver. Sender sends more frames. Each acknowledgement is labelled with a respective frames sequence number. Precautions: There should not be duplicate sequence numbers. Example of Sliding window protocol; […]

Stop and Wait

A transmitter transmits the frame. Transmitter wait for the acknowledgement for fixed period of time. On receiving valid frame, receiver send back an acknowledgement for next frame. On receiving acknowledgement transmitter transmit next frame. If sender not received any acknowledgement within time duration it re-transmit the same frame. The rate of transmission depends on the processing power […]

Byte count framing method

We had seen in previous article framing, that to send packets from sender to the receiver framing is required. But the question was how the receiver will identify the starting and ending of a frame. For receiver, starting and ending of a frame is necessary to recognize the next frames transmitted by the sender. So […]

Framing

To provide service to the network layer, the data link layer must use the service provided to it by the physical layer. As seen in the image above, the data link layer uses the services of the physical layer. In following steps data link layer received bits from the physical layer. Physical layer accept raw […]

Data Link Layer

Data link layer is the second layer in OSI model. As shown in image: As seen in the image above, the data link layer uses the services of the physical layer. These services are used in lending and receiving the bits over the communication channel. Functions of data link layer: Providing a well-defined service interface […]

Net 47

CBSE NET Q. An analog signal has a bit rate of 6000 bps and a baud rate of 2000 baud. How many data elements are carried by each signal element ? (A) 0.336 bits/baud (B) 3 bits/baud (C) 120,00,000 bits/baud (D) None of the above Ans: (B) Explanation: A same signal has bit rate of […]

Net 43

CBSE NET JUNE 2012 PAPER II Q. Page Shift Keying (PSK) Method is used to modulate digital signal at 9600 bps using 16 level. Find the line signals and speed (i.e. modulation rate). (A) 2400 bauds (B) 1200 bauds (C) 4800 bauds (D) 9600 bauds Ans: (A) Explanation: To calculate baud rate, modulation have to […]