From the website:

Quagga is a routing software suite, providing implementations of
OSPFv2, OSPFv3, RIP v1 and v2, RIPv3, BGPv4 and experemental ISIS
for Unix platforms, particularly FreeBSD and Linux and also NetBSD, 
to mention a few. Quagga is a fork of GNU Zebra which was developed 
by KunihiroIshiguro. The Quagga tree aims to build a more involved 
community around Quagga than the current centralised model of GNU Zebra.

WWW: http://quagga.net/