Abstract: A communication method applied to a communication system is provided for enhancing communication performance such as a throughput and a turn around time in the so-called intra-computer communication. In the communication procedure, when a source end system (SES) like a host computer transfers data to a destination end system (DES) such as a LAN or a WAN through a communication control system (CCS), the CCS served as a virtual destination receives the data and transmits an acknowledge (+Cresp) to the SES. In response to the acknowledge (+Crest), the SES performs the next transfer of the data. In response to the last acknowledge, the SES operates to output an indication about completion of the data transmission (End TX-C). The CCS continues to transfer the data temporarily received from the SES to the DES unless the CCS receives the acknowledge from the DES. The acknowledge +Cresp contains information about an amount of data transferred from the CCS to the DES.