[__monadic]

+1 to @jbeda, but let me offer some comments for the avoidance of possible confusion among potential Weave users.

Weave aims to deliver a completely portable network. In other words if you create an application using Docker container and a Weave network, that should be able to run anywhere. And all this should be 'magically simple'. Once you have decided where to run your app, you may wish to trade portability for performance gains. For example by using GCE networking (or Azure, or ...).

To date Weave achieved portability by sending some packets (inter host) through user space. This has big benefits in terms of ease of use eg. dealing with wide area networks, multicast and firewalls. But under load it performs worse than kernel-only models.

We now have Weave "fast data path" - http://blog.weave.works/2015/06/12/weave-fast-datapath/ ... This aims to deliver close to line performance with portability and extreme ease of use.

There may of course be yet more optimisations that end users wish to investigate. If you are willing to sacrifice some portability you could certainly make use of fast networks provided by a specific public cloud. We haven't yet seen a strong need to support this, but it is certainly a reasonable thing.

(Disclaimer: I work at Weaveworks)