Internet-2 is the advanced computer network technology supported by high performance gigabit backbones and isolated from the commercial payload of the public ordinary Internet. To create the tomorrow's Internet among academia, industry and government, the University Corporation for Advanced Internet Development (UCAID), Internet-2 consortium being led by US universities working in partnership with industry and government, was established to develop and deploy advanced network applications and technologies based on the Internet-2 platform. Over 200 research universities and laboratories in North America are connected by the advanced network of Internet-2.
Because of its high throughput and short response time, Internet-2 is an ideal computer network for medical imaging applications. However, the global access of Internet-2 cannot retain the high network performance as what we get within the US continent. It is because there is a bottleneck at the international link between Internet-2 in the US and the international network peer. For the international connection to Hong Kong Academic and Research Network (HARNET) in Hong Kong, the available bandwidth is limited by 45 Mbps. Furthermore, the choice of interconnection point, StarLight, leads to a network looping in the US and thus increases round-trip response time by 53 ms at least.
Considering the connection between the IPI/USC and the PolyU, the total round-trip response time is 292 ms. If the default TCP/IP settings are used, the upper limit of throughput under such a long round-trip response time is 1.75 Mbps only. An automatic tuning protocol is derived under Linux platform. The protocol is aimed at tuning the window size seamlessly and automatically to increase the network throughput. The experimental result shows that the tuning protocol can increase the maximum throughput to 22.4 Mbps, which is above 50% of the available bandwidth. The protocol will be beneficial to the applications such as teleradiology and teleconsultation in clinical environment because this method can yield fast round-trip response and high network throughput without any user intervention.
Figure 1. Internet 2 testbed between Hong Kong PolyU and USC Configuration
Figure 2. International internet-2 project connectivity