This series of patches introduces the ability for a BGP router, to configure a route distinguisher and associate import and export route targets. This permits for a BGP update to be sent with BGP extended communities associated to the exported route targets of the RD. This permits for a BGP update to be received, and to be handled according to the imported route targets of the RD contained in BGP extended communities. This patch is rebased with latest from master branch. It also relies on RD/RT discussions. It implements partial option 6, that is to say introduction of vrf subnode under bgp router node, and subsequent rt/rd vty commands. The testing on this patch shows the ability of route processing bgp updates with associated extended communities ( according to RT export values). Route server configuration with vpnv4 has also been showed to work. The second version of this patch is adding some documentation. It also fixes an issue related to initialisation of bgp vrf context. Cheers, Philippe