A scheme for avoiding frequent reduction of TCP congestion window on Mobile IP SHAKE

We have developed a system that increases the speed and reliability of communication of mobile computers, called Mobile IP SHAKE (SHAring multipath procedure for a cluster networK Environment). It lets mobile node construct a temporary network with neighboring mobile nodes through local high-speed links in order to communicate with a host outside of the local network. In Mobile IP SHAKE, a mobile node uses both its own link and the links of other hosts in the local network simultaneously and disperses the traffic to multiple links between the local network and the external host. Because of the different delay of links between the external nodes and the nodes in the local network, arrival of the packets at the receiver tends to be out of order. This paper addresses a problem that flequent useless retransmission due to unnecessary duplicate TCP ACKs caused by arrival of out of order segments. We propose a scheme to solve this problem. In this scheme, a Home Agent(HA) of mobile IP deletes unnecessary duplicate ACKs by managing a sequemce number of segments transmitted on each links and a mobile node selects a link that can transmit a segment earliest to HA by using round trip time between HA and the sending node.