Business Computing Environment and Network
Lab - 1 REPORT
TCP: Transmission Control Protocol
SUMMARY:
The idea of TCP congestion control is for each sender to determine the available capacity in the network so that it knows how many packets can be safely transmitted. The congestion window is a state variable for each connection which is used by the sender to limit how much data a sender can transmit into the network before receiving an acknowledgement. This report consist of the simulation of different model of TCP transmission which demonstrates the congestion control using the variation of dynamic window size implemented by TCP (Transmission Control Protocol). Various models are considered where packet drop rates are varied for demonstration of different situations from …show more content…
Answer:
When there is congestion in the network and the receiver did not receive the packet transmitted, there is no acknowledgement sent by the receiver and the sender continues to retransmit. In this process a new sequence number cannot be generated by the sender until the old sequence number is delivered. Because of this the segment sequence number remains unchanged.
Question 2:
Analyze the graph that compares the Segment Sequence numbers of the three scenarios. Why does the Drop_NoFast scenario have the slowest growth in sequence numbers?
Answer:
On observing the graph of sequence numbers between three scenarios(No_DROP,DROP_NoFast,DROP_Fast) we know that the DROP_NoFast scenario has the slowest growth in sequence number because of the below factors.
a) Packet discard ratio is set to 0.5% in performance metrics which implies there is high rate of packets being dropped.
b) Fast retransmit and fast recovery techniques in TCP are disabled which implies rate of sequence number of packets is