Xuxiaohu,
> Is extranet is a normal requirement for Layer3 DC network > virtualization overlay? I haven't seen any description of this in the > NVo3 requirement and framework drafts yet. Since we have not been able to fully pursue it as a requirement in nvo3, we have created a separate requirement document (http://tools.ietf.org/html/draft-fang-l3vpn-end-system-requirements-00) in l3vpn WG where it is stated as a requirement: "A network virtualization solution should allow a VM or application end-point to directly access multiple VPNs without a need to traverse a gateway. It is often the case that SP infrastructure services are provided to multiple tenants, for example voice-over-IP gateway services or video-conferencing services for branch offices. A network virtualization solution should support both, isolated VPNs and overlapping VPNs (often referred to as "extranets"), as well as both, any-to-any and hub-and-spoke topologies." Maria
