BSD Router Project: Open Source Router Distribution
Don't buy a router: download it !
BSD Router Project (BSDRP) - is an embedded free and open source router distribution based on FreeBSD with Quagga and Bird.
Quagga - is a routing software suite, providing implementations of OSPFv2, OSPFv3, RIP v1 and v2, RIPng and BGP-4 for Unix platforms, particularly FreeBSD, Linux, Solaris and NetBSD. Quagga is a fork of GNU Zebra which was developed by Kunihiro Ishiguro. The Quagga tree aims to build a more involved community around Quagga than the current centralised model of GNU Zebra.
Bird (The BIRD Internet Routing Daemon) - The BIRD project aims to develop a fully functional dynamic IP routing daemon primarily targeted on (but not limited to) UNIX-like systems and distributed under the GNU General Public License.
iXsystems - Enterprise Servers, Storage and Solutions for Open Source.