Quagga is a routing software suite, providing implementations of
OSPFv2, OSPFv3, RIP v1 and v2, RIPv3 and BGPv4 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 Kunihiro
Ishiguro. The Quagga tree aims to build a more involved community
around Quagga than the current centralised model of GNU Zebra.

GNU Zebra is a free software (distributed under GNU Generic Public
License) which manages TCP/IP based routing protocols.
It supports BGP-4 protocol as described in RFC1771 (A Border Gateway
Protocol 4) and RIPv1, RIPv2 and OSPFv2.

Zebra is intended to be used as a Route Server and a Route Reflector.
Zebra is not a toolkit, it provides full routing power under a new
architecture.