Dominik Charousset: Implementation of a Middleware for Hybrid Adaptive Multicast (HAMcast)

The Hybrid Adaptive Mobile Multicast (HAMcast) API offers a generically accessible, hybrid multicast service via a modular extensible middleware. It's main objective is to provide a globally available multicast service following the insight that group communication is most efficiently implemented on the lowest layer available. Thus HAMcast does not only implement an overlay multicast mechanism, but uses overlay technologies to interconnect regions between native multicast boundaries.

The HAMcast middleware follows a late binding strategy for multicast sockets (technology selection and binding at runtime instead of service determination at compile time) and enables HAMcast-based multicast applications to use technology-independent group identifiers by defining a new way of ID/Locator split.

Some of the main challenges for the implementation of the HAMcast middleware are:

• a generic interface for native and overlay multicast modules must be defined;
  
• mapping of identifiers to locators including service selection based on the results of the service discovery (choosing the most efficient layer available);
• fast Inter-Process Communication (IPC) between the middleware and HAMcast applications is needed to keep the costs of the HAMcast layer negligible as compared to native multicast applications.

This presentations introduces the software concepts of the HAMcast middleware, design decisions and the current state of the implementation.

Presentation Slides