FreeBSD's implementation of Radix tree was chosen.
"Surya project aims to improve IPv4 forwarding path scalability. Improving forwarding scalability enables a Solaris machine to forward a higher number of packets per second to a greater number of destinations described in the forwarding table."
The Surya project is ready to code review. You can participate in discussion at networking-discuss.
Design doc is available at http://www.opensolaris.org/os/community/networking/surya-design.pdf.