In congestion avoidance, the timeout involves F-RTO as described above.
In this streamlined simulator, main functions of TCP such as sliding window, slow start, congestion avoidance, retransmission, retransmission timeout (RTO) calculation, and selective ACK (SACK) are included [12].
Like TEAR [24], a well-known receiver-driven TCP-based flow control solution, SCTP- Rev + runs seven states at receiver side for flow control, which are Slow Start, Congestion Avoidance, Slow Start Ready, Timeout, Congestion Avoidance Ready, and Fast Recovery.
Among other findings, it is additionally shown that the ratio between spurious timeouts and other congestion recovery events experienced by TCP flows is low, indicating a negligible impact of spurious timeouts on TCP performance.
Our modification can avoid unnecessary retransmission and reduction of congestion window invoked by spurious timeouts during handover.
The RTO holds transmission of normal packets during timeout and reduces its congestion window to 1 after the timeout.
This problem causes the TCP source to unnecessarily decrease its congestion control window once a retransmission timeout (RTO) occurs, resulting in low network throughput.
Meanwhile, a TCP sender can invoke congestion control due to the acknowledgment timeout of a packet while BS is still attempting to transmit the packet in the wireless link.
TCP Westwood and TIBET show the poor fairness as some connections suffer severely from frequent timeouts due to small congestion window size.
A problem common to packet markers used in DiffServ architectures is the provision of Quality of Service to TCP flows: specifically, short-lived TCP flows suffer from packet losses at small congestion windows, which inevitably leads to lengthy retransmission timeouts.
