Researchers have recently proposed many new Internet architectures and overlay networks (for example, RON, i3, HIP) in order to add new functionality to the Internet. However, users are often unwilling to switch from their favorite applications just for leveraging the new functionality offered. It is thus important to enable legacy applications (for example, Internet Explorer, Firefox, ssh) to work on new architectures and overlays. Rewriting/recompiling all legacy applications for each new architecture is a tedious and often impossible task.
OCALA is an overlay convergence architecture that allows legacy applications to leverage the functionality of new architectures and overlays without any source code modification, recompilation or reconfiguration. OCALA allows a user to simultaneously access multiple overlays for different purposes, stitch together the varied functionality offered by different overlays, as well as communicate with hosts residing in overlays the user is not directly connected to. Furthermore, OCALA factors out the common requirements for supporting legacy applications -- researchers can concentrate on designing new network architectures, rather than getting legacy applications to work.
We envision the following usage scenario for OCALA. Researchers who develop new network architectures, write an OCALA plugin for their architecture. They functionality of the new architecture is advertised to real users via an Internet Architecture Plugins webpage. Users wishing to benefit from the new functionality, click on the download link of the relevant OCALA plugins. The OCALA plugin is automatically downloaded and incorporated into the OCALA proxy which runs on the user's machine. A graphical user interface allows the user to select the connections that will use the new network architecture. For example, the user can specify that all ssh connections should use RON while Internet relay chat should use i3. Users wishing to stitch together the functionality offered by different overlays and to communicate across multiple overlays will use a publicly available OCALA gateway service. Thus, users immediately benefit from the functionality offered by new network architectures, while researchers obtain a large test bed of real users for experimenting with their innovative designs.