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In stop-and-wait ARQ why shoukld the receiver always send an acknowledgement message each time it receives a frame with a wrong number sequence?
Wiki User
∙ 12y ago
When the receiver receives a good data packet, it sends an acknowledgement packet to the transmittor with a sexquence number of the NEXT packet it expects. That means, if the člast received data block has a sequence number 0, then the ACK contains sequence number 1, because the next block the receiver expects, ought to contain seq. number 1.
Wiki User
∙ 12y ago
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What purpose does the acknowledgement number in TCP do?
It acknowledges receipt of the previous packet in the sequence.
Write a note on Error-Detection Codes?
To make sure all the frames are delivered to the receiver in proper order a protocal calls for the receiver to send back special control frames bearing positive and negative acknowledgements about the incoming frames.If the sender receives a positivev acknowledgement it is termed that the frames have reached safely on the other hand if is negative the frame must be transmitted again. There are chances that due to hardware problems (i.e noise burst) some frames may get vanished. In this case, the protocol waiting for the acknowledgement, would hang forever. To nullify this effect a timer is introduced. When the sender transmits a frame it also starts the timer. The timer is set to go off long enough for the frame to reach the destination, be processed there, have an acknowledgement propagate back to the sender. If either the frame or the acknowledgement is lost the timer goes off automatically alerting the sender to transmit the frame again. Sequence numbers are provided to the frames so that the receiver can distinguish if the frames are repeated again.
Which protocol uses sequence numbers and acknowledgement numbers?
TCP is a protocol that uses those.
Is it possible that a receiver may accept multiple copies of the same frame when none of the frames are lost?
when the transmission medium has such a longlatencythat the sender's timeout runs out before the frame reaches the receiver. In this case the sender resends the same packet. Eventually the receiver gets two copies of the same frame, and sends an ACK for each one. The sender, waiting for a single ACK, receives two ACKs, which may cause problems if it assumes that the second ACK is for the next frame in the sequence.
In protocol rdt3.0 the ACK packets flowing from the receiver to the sender do not have sequence numbers although they do have an ACK field that contains the sequence number of the packet they are?
To best answer this question consider why we needed sequence numbers in the first place. We saw that the sender needs sequence numbers so that the receiver can tell if a data packet is a duplicate of an already received data packet. In the case of ACKs, the sender does not need this info (i.e. a sequence number on an ACK) to tell detect a duplicate ACK. A duplicate ACK is obvious to the rdt3.0 receiver, since when it has received the original ACK it transitioned to the next state. The duplicate ACK is not the ACK that the sender needs and hence is ignored by the rdt3.0 sender.
What is maximum likehood detection?
Say there are n possible input sequences that is A1 to An. Coded sequence B is transmitted. At receiver end due to noise sequence R is obtained. Than we will calculate P(Ai/R) for i = 1 to n. Decoded sequence A for which the probability is maximum is decoded maximum likelihood sequence.
One of the nine pins on a serial port transmits data in a sequence of bits and a second pin receives data?
RS232 DB9 connectors Receives data serially from Pin No. 2 & Transmits data from Pin No.3.
How does tcp handle data sequencing?
TCP Breaks User Data Into Segments, Numbers Each Segment, Places Them In The Correct Sequence, And Sends Each In Order, Waiting For An Acknowledgement Before Sending The Next Segment.
Which two TCP header fields are used to confirm receipt of data?
The Transmission Control Protocol (TCP) is a core protocol of the Internet protocol suite. The sequence number and acknowledgement number are used to confirm receipt of data.
What is the Vhdl code of rake receiver?
vhdl is a hardware definition languega to be run on a dsp. it describes circuits, a logical hardware structure. a rake receiver is a piece of hardware that enables every WCDMA-receiver (e i a mobile working with the umts standard) to handel a cdma-coded bit sequence. i know... cant describe it in an easier way.... ;)
What to do if the UDP receives datagrams that are not in sequence?
Since, there is no error checking in UDP. Datagrams will be passed to the next OSI layer without rearranging or in the order by the same which was received and it will not be dropped.
Suppose that a stop and wait ARQ system has a time out value that is less than the time required to receive an acknowledgement Sketch the sequence of frame exchanges that transpire between two station?
suppose that a stop and wait ARQ system has a time out value that is less then the time required to receive an acknowledgement. sketch the sequence of frame exchanges that transpire between two stations when station A sends five frames to station B and no errors occur during trasmission. what is a mail server? briefly explain specifying the protocols involved, how a sender can send a mail to the server and the recipient retrieves it from the server? what is datagram
