What is AIMD in TCP congestion control?

What is AIMD in TCP congestion control?

The additive-increase/multiplicative-decrease (AIMD) algorithm is a feedback control algorithm best known for its use in TCP congestion control. AIMD combines linear growth of the congestion window when there is no congestion with an exponential reduction when congestion is detected.

How TCP congestion control is implemented at AIMD?

Transmission Control Protocol (TCP) uses a network congestion-avoidance algorithm that includes various aspects of an additive increase/multiplicative decrease (AIMD) scheme, along with other schemes including slow start and congestion window (CWND), to achieve congestion avoidance.

How does TCP handle congestion control?

TCP detects congestion when it fails to receive an acknowledgement for a packet within the estimated timeout. In such a situation, it decreases the congestion window to one maximum segment size (MSS), and under other cases it increases the congestion window by one MSS.

How does fast retransmit work?

Fast retransmit is a modification to the congestion avoidance algorithm. As in Jacobson’s fast retransmit algorithm, when the sender receives 3rd duplicate ACK, it assumes that the packet is lost and retransmit that packet without waiting for a retransmission timer to expire.

How does TCP Reno work?

TCP Reno: TCP Reno includes algorithms named Fast Retransmit and Fast Recovery for congestion control. Fast Retransmit: When the sender receives three duplicate acknowledgements of a sent packet then sender retransmit it without waiting for the time out.

What causes TCP fast retransmission?

TCP Fast Retransmission – Occurs when the sender retransmits a packet before the expiration of the acknowledgement timer. Senders receive some packets which sequence number are bigger than the acknowledged packets. Senders should Fast Retransmit upon receipt of 3 duplicate ACKs.

How does TCP flow control work?

Flow Control in TCP Flow control deals with the amount of data sent to the receiver side without receiving any acknowledgment. It makes sure that the receiver will not be overwhelmed with data. It’s a kind of speed synchronization process between the sender and the receiver.

What are the congestion control techniques used by TCP Mcq?

Congestion Control MCQ Question 2 Detailed Solution ​Hence the correct answer is Additivity. To avoid congestion, the sender TCP has two strategies: one is a slow start and additive increase, and the second is called multiplicative decrease.

What is source based congestion avoidance?

Congestion avoidance is a flow control mechanism. A system configured with congestion avoidance monitors network resources such as queues and memory buffers. When congestion occurs or aggravates, the system discards packets.

Does Fast Retransmit reduce congestion?

Finally, there is another improvement we can make. Using the fast retransmit mechanism the sender detects a possible loss of a transmitted packet, implying congestion, and therefore, it is necessary to reduce its congestion window accordingly, after the transmission of the lost packet.