Effect of TCP Buffer Size on the Internet Applications

The development of applications, such as online video streaming, collaborative writing, VoIP, text and video messengers is increasing. The number of such TCP-based applications is increasing due to the increasing availability of the Internet. The TCP protocol, works at the 4th layer of the Internet model and provides many services such as congestion control, reliable communication, error detection and correction. Many new protocols have been proposed such as stream control transmission protocol (SCTP) with more features compared to the TCP. However, due to the wide deployment, TCP is still the most widely used. TCP creates the segments and transmit to the receiver. In order to prevent the errors TCP saves the segments into the sender buffer. Similarly, the data is also saved at the receiver buffer before its transmission to the application layer. The selection of TCP sender and receiver buffer may be varied. It is very important because many applications work on the smartphones that are equipped with a small amount of memory. In many applications such as online video streaming, some errors are possible and it is not necessary to retransmit the data. In such case, a small buffer is useful. However, on text transmission the complete reassembly of message is required by the TCP before transmission to the application layer. In such case, the large buffer size is useful that also minimizes the buffer blocking problem of TCP. This paper provides a detailed study on the impact of TCP buffer size on smart-phone applications. A simple scenario is proposed in NS2 simulator for the experimentation.