OASIS (Overlay Anycast Service InfraStructure) is a locality-aware server selection infrastructure. At a high level, OASIS allows a service to register a list of servers, and then, for any client IP address, answers the question, ``Which server should the client contact?'' Server selection is primarily optimized for network locality, but also incorporates factors like liveness and, optionally, load. OASIS might, for instance, be used by CGI scripts to redirect clients to an appropriate download site for large files. It could be used by IP anycast proxies to locate servers. Currently, in addition to a simple web interface, we have implemented a DNS redirector that performs server selection upon hostname lookups, thus supporting a wide range of unmodified legacy client applications.
Their homepage demo apparently is supposed to show a circle on the embedded map showing my location -- it's not working for me here from CodeCon, even after typing in my external IP address.
From the overview, it's clear that the reference solution OASIS has in mind for comparison is probing a new IP address from multiple sites on-demand at the moment they want to know the right server. But, they report this solution has problems: latency and too much redundant traffic probing IPs that are near each other. So OASIS is constantly mapping network blocks in the background, and remembering and updating its results for lags and geographic location guesses. Because this effort is ongoing, amortized over time and over diverse applications, the costs in latency and traffic are less than the naive on-demand solution. In fact, as more applications share the same location architecture, the marginal cost for each new one drops.
There would seem to be some overlap with the constant, distributed net-mapping done by the net DIMES project based at Tel-Aviv University.
There's already a OASIS abbrieviation in use in technical/internet circles: "a non-profit, international consortium that creates interoperable industry specifications based on public standards such as XML and SGML." So yet again at CodeCon, this is a bad project name on uniqueness grounds alone. (Not to mention: how is a worldwide always-on active map of the Internet anything like a remote desert oasis?) Do we need a boot camp that teaches engineers to pick better evocative and unique project names?