Grid computing infrastructures and applications are increasingly diverse with networks ranging from very high bandwidth optical networks to wireless networks and applications ranging from remote visualization to sensor data collection. For such environments, standard transport protocols such as TCP and UDP are not always sufficient or optimal given their fixed set of properties and their lack of flexibility. As an alternative, we present H-CTP, a high-performance configurable transport protocol that can be used to build customized transport services for a wide range of grid computing scenarios. H-CTP is based on an earlier configurable transport protocol called CTP, but with a collection of optimizations that meet the challenge of providing configurability while maintaining performance that meets the requirements of such demanding applications. This paper motivates the need for customizable transport in this area, presents the design of H-CTP, and gives results from performance studies that compare H-CTP with both CTP and TCP. These show, for example, that H-CTP is able to achieve throughput of over 900 Mbps across Gigabit links. Three diverse grid scenarios are used as example applications and for the H-CTP/TCP comparisons: remote visualization, fast message passing, and sensor grids.

The notion of lambda-Grids posits plentiful collections of computing and storage resources richly interconnected by dedicated dense wavelength division multiplexing (DWDM) optical paths. In lambda-Grids, the DWDM links form a network with plentiful bandwidth, pushing contention and sharing bottlenecks to the end systems (or their network links) and motivating the group transport protocol (GTP). GTP features a request-response data transfer model, rate-based explicit flow control, and more importantly, receiver-centric max-min fair rate allocation across multiple flows to support multipoint-to-point data movement. Our studies show that GTP performs as well as other UDP based aggressive transport protocols (e.g. RBUDP, SABUL) for single flows, and when converging flows (from multiple senders to one receiver) are introduced, GTP achieves both high throughput and much lower loss rates than others. This superior performance is due to new techniques in GTP for managing end system contention.