1. GO- BACK N ARQ TEAMS: BANDWIDTH BROTHERS DEADLOCK FOSTERS NEW CREATORS ROTHMANS

2. INTRODUCTION CONCEPT OF PIPELINING IMPROVING THE EFFICIENCY OF TRANSMISSION WHY ITS CALLED GO- BACK N ARQ CONCEPT OF SEQUENCE NUMBERS, SLIDING WINDOW, TIMERS ,ACKNOWLEDGEMENT AND RESENDING FRAME.

3. DISADVANTAGES OF STOP AND WAIT 1) Efficiency is very less if channel is thick and long. Thick means channel has large bandwidth. Long means the round trip is delay product of these two is called bandwidth delay product... 2) There is no pipelining because we need to wait for a frame to reach the destination and be acknowledged before the next frame can be sent.

4. PIPELINING In networking if a task is often began before the previous task ended. This is known as PIPELINING.

7. Send window after sliding Sf Sn

8. Receive window before sliding Rn

9. Receive window after sliding Rn

11. Effective transmission ratae.

13. RECEIVER WINDOW

14. PIGGYBACKING Control signal is attached with Data signal. Request Window  Sender Window Arrival Window  Both Window {Data, Control} Used to improve the efficiency of the Bidirectional Protocol. Carries control information about arrival or lost frames Both Sender and the Receiver window use a timer and are involved in three types of events. Request. Arrival. Time-out. Both site must use the same Algorithm.

17. Second, the remote node requests retransmission of the missing frame using a control frame (sometimes called a NACK or REJECT). The receiver discards all frame s which do not have the number of the requested frame.

19. DISADVANTAGES OF GO-BACK N ARQ Buffer requirement: Transmitter needs to store the last N packets Scheme is inefficient when round-trip delay large and data transmission rate is high Retransmission of many error-free packets following an erroneous packet When RTT is large: for a high number of NACK, a lot of BW is wasted If NACK is lost , a long time is wasted until re-transmission of all packets (until another NACK is sent).

20. Selective Repeat ARQ To overcome the disadvantages of GO BACK N ARQ, we use Selective Repeat ARQ To utilize more bandwidth

21. COMPARISON CHART

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