Self-adaptive Network Control Transmission Method and System Based on TCP

A self-adaptive network control transmission system based on TCP, including sender and receiver, network coding layers are added between transmission layer and IP layer on both sender and receiver, wherein:

• the network coding layer of the sender includes two control transmission modules:
• one is used to deal with the packets which are sent from transmission layer on sender, this module encodes the data packets and puts specific variables in the network-coding headers, the variables include a linear coefficient vector γ and a variable pktID, and will be extracted by the network coding layer on the receiver, the vector γ is for decoding and the variable pktID will be evaluated to a new variable echo_pktID in the network coding layer of the receiver;
• the other module is used to deal with the ACK packets which are sent from the receiver, this module subtracts the network-coding headers of ACK packet and gets echo_pktID, uses echo_pktID to determine whether it is time to change R, if echo_pktID equals the number of W+10*R_old or is larger than W+10*R_old for the first time, then the redundancy factor R is changed as follow:
• use the loss to figure out the number of diff_loss_new in the network coding layer of the sender, that is diff_loss_new=loss−loss_old, wherein loss_old indicates the value of loss in ACK pocket when the last time to change R, and diff_loss_new indicates the difference between two adjacent losses;
• use diff_loss_new to figure out the value of R_new, that is R_new=R_old+2*(diff_loss_new/10)+(diff_loss_old/10), wherein diff_loss_old indicates the value of diff_loss_new when the last time to change R;
• refresh the variables in the network coding layer of the sender, that is R_old=R_new, loss_old=loss, diff_loss_old=diff_loss_new, W=W+10*R_new;
• the network coding layer of the receiver includes two modules:
• one is used to deal with ACK packets which are sent from transmission layer, the module determines whether the ACK packet is used to found the connection, if so, sends the ACK packet to the IP layer;
• if not, discards it and returns back to wait;
• the other module is used to deal with the coding packets which are sent from the sender, if the module receives a coding packet from the IP layer, it will subtract the network-coding header and extract the coding coefficient vector γ and pktID, and decode to get the initial packet, meanwhile it will create a new ACK packet which contains the two variables, loss and echo_pktID in the network-coding header, and send the new ACK packet to the IP layer.