Beka is a fairly basic BGP speaker. It can send and receive unicast route updates in IPv4 and IPv6, but not too much else. It is designed to be simple to use and to extend, without too much overhead.

It uses eventlet for concurrency, but is easy enough to port to gevent if that takes your fancy.

More information at https://github.com/faucetsdn/beka