What are TCP retransmissions?

What are TCP retransmissions?

The TCP retransmission means resending the packets over the network that have been either lost or damaged. Here, retransmission is a mechanism used by protocols such as TCP to provide reliable communication.

How many TCP retransmissions are there?

tcp_retries2 (integer; default: 15; since Linux 2.2) The maximum number of times a TCP packet is retransmitted in established state before giving up. The default value is 15, which corresponds to a duration of approximately between 13 to 30 minutes, depending on the retransmission timeout.

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.

What is the meaning of retransmission?

: to transmit (something) back or again retransmit a signal retransmitting data If the system sends a document and gets a busy signal, it will automatically try to retransmit after a preset interval. — Datamation.

What is retransmission rate?

RR stands for Retransmission Rate. RR is defined as the ratio of retransmitted packets to the total number of packets in a conversation.

Does UDP have retransmission?

UDP has a number of benefits for different types of applications, including: No retransmission delays – UDP is suitable for time-sensitive applications that can’t afford retransmission delays for dropped packets.

What is the meaning of Fast Retransmit?

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.

What is the difference between Fast Retransmit and fast recovery?

With using only Fast Retransmit, the congestion window is dropped down to 1 each time network congestion is detected. Thus, it takes an amount of time to reach high link utilization as before. Fast Recovery, however, alleviates this problem by removing the slow-start phase.