Collage evolved from the Equalizer network library. Now it’s used by a few other projects as well, and I’ve been mentioning it quite a few times on this blog already.
Looking back over the last seven years of Equalizer, Collage has received by far the largest investment in manpower compared to all the other components. It seems innocent enough, but trust me, getting a distributed network library right and bug free is no small task. On the one hand, the ‘fun’ implementation of the Windows IP stack (WSASYSCALLFAILURE and stack corruptions) took a lot of debugging to get going, and on the other hand advanced features such as InfiniBand support (thanks Dardo!) and fast, reliable multicast are no small task to implement.
What’s wrong with boost::asio?
Nothing. It provides about the same functionality as co::Connection and co::ConnectionSet. We use it as the UDP backend for the RSP multicast implementation. It wasn’t around when I started eq::net, which became Collage. We’ld love to replace co::Connection and co::ConnectionSet with it, but the effort of porting the RDMA and RSP connections to asio has prevented this so far. Ultimately Collage tries to provide higher level abstractions.
What’s wrong with 0MQ?
Again: Nothing. It provides higher level abstractions then asio. It’s less likely that we’ll use it as the backend for Collage, since some of the design decisions are somewhat different from what Collage is doing.
So, what’s next?
Collage, similar to Lunchbox, aims to provide high-level abstractions. Similarly to the introducing Lunchbox series, I’ll present them over the next few weeks. In the same timeframe, we are planning to separate the Equalizer and Collage projects as well as to define and document the ‘1.0’ Collage API.
For now, you can find a technical overview presentation on the Collage website. Enjoy!