Method for adaptively determining packet delayed sending for Semi-TCP (transmission control protocol)

Abstract

The invention discloses a method for adaptively determining packet delayed sending for Semi-TCP (transmission control protocol). In the method, after receiving a TCP packet, a destination node using the Semi-TCP adaptively determines the time of sending an acknowledgement packet of a data packet, thus the sending quantity of the ACK (acknowledgement) packet is compressed, the sending of repeated ACK is canceled, and the competition for a wireless channel between a positive data flow and a negative data flow is reduced; and an acknowledgment state is a state described by the following parameters: continuity of packets in a receiving cache of the destination node, the maximum number of block boundaries which can be contained by a selective acknowledgement (SACK) packet head, a set time interval of sending ACK and the like. Meanwhile, in the method, the traditional SACK packet head is improved, and the sequence numbers of discontinuous TCP block boundaries are marked by a relative offset so as to improve the acknowledgment rate of the Semi-TCP source node packet and reduce the overhead resulting from the introduction of SACK.

Description

technical field [0001] The present invention relates to the technical field of TCP (Transmission Control Protocol) in a multi-hop wireless network, in particular to a method for delayed transmission of self-adaptive acknowledgment packets for quasi-TCP, that is, Semi-TCP. Background technique [0002] Different from traditional wired networks, in multi-hop wireless networks, besides network congestion, many non-network congestion factors will also cause data packet loss or damage, such as channel quality instability, wireless channel Competition, mobility of nodes, volatility of energy supply, and user behavior. These factors often cause the TCP layer to make a misjudgment of network congestion and mistakenly trigger the corresponding congestion control mechanism to reduce the sending window, resulting in a decrease in network performance. For this reason, researchers have proposed many improved schemes for TCP in multi-hop wireless networks, but these schemes still rely on...

AI Technical Summary

Problems solved by technology

In this case, the reverse ACK packet may not be forwarded in time due to fierce competition, and eventually the source node retransmission timer (Retransmission Timeouts, RTO) will expire and trigger data packet retransmission, resulting in a waste of bandwidth

On the other hand, the reverse ACK packet may even be discarded due to multiple sending failures, eventually triggering the source node or destination node to re-initiate the route establishment process, which will have a more obvious negative impact on network performance

At the same time, the ACK mechanism of traditional TCP uses repeated ACKs. Once a packet loss occurs in the network, the destination node will send a large number of repeated ACK packets, which will further intensify the competition in the wireless channel.

Since Semi-TCP does not rely on these reverse repeated ACKs for congestion control, sending a large number of ACKs at this time will only waste network resources and seriously affect the throughput of TCP streams

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