I have reviewed this document as part of the Operational directorate's ongoing effort to review all IETF documents being processed by the IESG.  These comments were written primarily for the benefit of the operational area directors. Document editors and WG chairs should treat these comments just like any other last call comments.   I think this document is written very clear and has covered many areas (some of which is actually out of the NVO3 scope, e.g. Section 9 Federated NVAs).     Some comments: -         Figure 1 should include Inter-VN gateway in the reference model. Majority of TSs communicate with TSs in different VNs, or to internet. The Diagram shown in the Figure 1 is more like the L2VPN. -         Section 3.1.1: Should emphasize that C-Tag might have to be changed (i.e. locally significant) if there is a bridged network attached to the NVE. As TSs being added, deleted, or moved, if C-Tag is not changed when a TS moves from one NVE to another NVE, it effectively requires unique C-Tags for all VNs across the VN domain (which beats the purpose of having overlay’s VN id).       Thanks, Linda