The goal of this project is to develop the components necessary to support a peer-to-peer group communication infrastructure that provides reliability, security, and fault-tolerance while enabling scalability. Applications such as shared remote visualization, shared virtual reality, and collaborative remote control of instruments require reliable and secure distributed information sharing and coordination capabilities. The collaborations using these applications are usually built in an incremental and ad hoc manner. This incremental and dynamic growth pattern is not well supported by a rigid server-based structure. Thus, the natural alternative to a server-based model is to provide a reliable and secure group communication infrastructure to support a dynamic and scalable peer-to-peer model.

There have been several systems that have addressed individual aspects of building a reliable and secure group communication capability, however, few have come close to providing a complete solution to the problem. This project is developing the components necessary to provide reliable and secure group communication mechanisms that scale to the Internet. The InterGroup protocols will be used to provide the reliable group communication services. These properties include reliable delivery of messages, ordered delivery of messages, and membership services. The Secure Group Layer will provide the secure group communication services including authorization and access control, key management, authenticity, integrity and/or confidentiality.

Collaborative applications need to support dynamic groups that can scale to large numbers of users. A peer-to-peer model inherently makes these applications easier to design and to operate for groups. Since there are no servers, groups can form ad hoc and there is no setup or scheduling with a centralized authority required. There are many DOE applications that can benefit from the use of a peer-to-peer group communication model. For example, this group communication model has already been used in a collaborative electronic notebook to provide distributed event notification services. With the advent of the DOE Science Grid and the availability of distributed resources, comes the need to provide distributed information sharing and coordination capabilities. As the DOE Science Grid begins to deploy, there will likely be a need for support of replicated services. A server can be a performance bottleneck, a single point of failure, and require significant administration. Group communication provides a natural mechanism for helping to maintain consistent state among a set of replicated servers. The group communication service provides group membership services, reliable ordered message delivery, and allows the system to make progress in the presence of process and network faults. In this model, users do not send traffic to other users but instead elect to receive traffic from a multicast group. This means that at any time a user may join a group, receive its traffic, and leave a group. Thus controlling access to a multicast group and establishing a secret session key for the group present a complicated set of problems.

There are two primary components to a reliable and secure group communication system. These components are a reliable group communication protocol and a Secure Group Layer. A peer-to-peer reliable multicast protocol combined with group security services can provide a secure scalable communication infrastructure in the Grid and the Internet. It is important that this service allow the group members to act as peers, trust the group to be secure and trust the delivery guarantees. This service must also scale to the Internet. InterGroup is a new group communication protocol under development at LBNL that is designed to be scalable to the Internet and provide a very flexible service model. The Secure Group Layer, also currently under development, is designed to provide security services for the InterGroup protocols. The InterGroup protocols will be developed in this project to provide the reliable group communication services. These properties include reliable delivery of application messages, ordered delivery of application messages, and membership services. The Secure Group Layer will provide the secure group communication mechanisms: authorization and access control, establishing session key, authenticity, integrity and/or confidentiality. We will develop, disseminate and support the InterGroup protocols and the Secure Group Layer for a select group of application developers, with the long-term goal of integrating these components into the DOE Science Grid infrastructure.

Year 1:

• InterGroup Alpha release testing and improvements identified during deployment
• Begin development of example applications
• Publish proof of security for Secure Group Layer key exchange algorithms.
• Limited prototype implementation of the Secure Group Layer using the InterGroup protocols.

Pervasive Collaborative Computing Environment, DOE Science Grid, and Self-Configuring Network Monitor