Fast Reinjection for Intermittent Multi-Path Connections

Work in Progress


A common use case for multi-path protocols such as mutli-path TCP is the simultaneous use of Wifi and cellular connections since smartphones nowadays provide such interfaces. The combination of multiple networks for Internet access, e.g. a local area network and wide area network, allows for continuous data transmission even in scenarios with an intermittent connection. One example is the loss of the Wifi connection in a mobile scenario in which a user leaves the connection range of the Wifi network. For a seamless handover between the connections, protocols have to detect the connection loss and have to retransmit lost packets of the lossed connection immediately, so that the receiving network stack can forward the packets in sequence to the application. Here, the behavior for detection of connection loss and the reinjection of lost packets after connection loss is carved out for multi-path TCP. The analysis of the protocol behavior shows that mechanisms that originate from single-path TCP and adopted to multi-path are slow to detect connection loss and cause therefore large application level delays. Furthermore, a new reinjection timer is proposed to speed up the reinjection of lost packets after a connection loss. The new approach is evaluated using different timer values and show that adaptation of the timer speed the recovery of lost packets after a connection loss.