MARWARI COLLEGE,RANCHI
(UNDER RANCHI UNIVERSITY RANCHI)
NAME : RAJU MANJHI,PRAKASH KUMAR
SUB: NETWORKING
SEM : IT IV
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Data Link layer:
What is Piggybacking .Explain the concept and disadvantages .
What is Piggybacking .Explain the concept and disadvantages .
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.
• A better
solution would be to use each channel (forward & reverse) to transmit frames
both ways, with both channels having the same capacity. If A and B are two
users. Then the data frames from A to Bare intermixed with the acknowledgements
from A to B.
• One more
improvement that can be made is piggybacking.
The concept is explained as follows:
The concept is explained as follows:
In two way
communication, Whenever a data frame is received, the received waits and does
not send the control frame (acknowledgement) back to the sender immediately.
The receiver
waits until its network layer passes in the next data packet. The delayed
acknowledgement is then attached to this outgoing data frame.
This
technique of temporarily delaying the acknowledgement so that it can be hooked
with next outgoing data frame is known as piggybacking.
• The major
advantage of piggybacking is better use of available channel bandwidth.
• The
disadvantages of piggybacking are:
1.
Additional complexity. . If the data link layer waits too long before
transmitting the acknowledgement, then retransmission of frame would take
place.
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