Hello draft-bl-nvo3-dataplane-requirements authors, I was reviewing this latest 02 draft fully with a special focus on all the "MUST" statements and have the following comments:
1) In Section 3.2.1 it says: "An L2 VNI MUST provide an emulated Ethernet multipoint service as if Tenant Systems are interconnected by an 802.1Q LAN over a set of NVO3 tunnels." Does this mean that the inner Ethernet frame must carry an 802.1Q tag? Maybe it can be reworded to make it clearer by explicitly saying something about VLAN tags. 2) In Section 3.2.1 it says: "Loop avoidance capability MUST be provided." What does loop avoidance mean in the data plane? Is split horizon forwarding enough? Is this implying that a TTL is needed in the encapsulation header (inside the outer IP header)? 3) In Section 3.2.1 it says: "As frames arrive from VAPs or from overlay tunnels, the MAC learning procedures described in IEEE 802.1Q are used:..." Is there a more specific reference to a part of 802.1Q that describes inner source MAC address to outer source address learning? It may confuse readers because this draft refers to inner MAC to outer L3 address. Is the reference to 802.1Q required? 4) In Section 3.2.1 it says: "Broadcast, Unknown Unicast and Multicast (BUM) traffic handling MUST be supported." It may be desirable for an operator to have the ability to disable unknown unicast (if there is a control plane to distribute MAC to L3 tunnel mappings), and also to disable multicast if it is a service that they do not want to support. Are you saying that an implementation must always forward unknown unicast and multicast, or that it must be "capable" of forwarding them if desired? 5) In Section 3.2.1 it says: "To achieve this, the NVE MUST support ingress replication and MAY support multicast over an overlay multicast tree." I don't see why ingress replication is a MUST if the underlay can support multicast. I think this should be reworded to be "To achieve this, the NVE MUST either support ingress replication or MUST support multicast across the underlay network if the underlay supports it." 6) In Section 3.3.2 it says: "From an encapsulation perspective the IPv4 and IPv6 encapsulations MUST be supported, MPLS tunneling MAY be supported." Requiring support for BOTH IPv4 and IPv6 seems too strong. Can this be changed to "MUST support IPv4 or IPv6 and should support both, MPLS tunneling MAY be supported." 7) In Section 3.3.2.1 : Is this mandating a specific entropy field in the encapsulation header, or would using the source UDP port or the GRE key qualify? If they would qualify, it would be good to add a sentence to say so. 8)In Section 3.3.2.3 it says: "L2 NVEs MUST support ingress replication and SHOULD support point-to-multipoint tunnels." Must seems strong for ingress replication. There should be a MUST support ingress replication or point-to-multipoint tunnels. Also, this is inconsistent with section 3.2.1 where p2mp tunnels are not mentioned but instead mentions an overlay multicast tree. Does a multicast tree qualify as a p2mp tunnel ? 9) General comment: In a few places there are instances of "must" and "may" that are not capitalized. Thanks, Larry _______________________________________________ nvo3 mailing list [email protected] https://www.ietf.org/mailman/listinfo/nvo3
