This RFE adds new volume connector types, 'port' and 'portgroup'. A volume connector with one of these types has a UUID of a port or portgroup. The types make it easier to get an IP address provided for a volume connector since we can get a VIF attached to the connector from port or portgroup.
For attaching an iSCSI volume to a node, a few cinder backend driver may require IP address of the node. If the storage network is managed by neutron, we can get an IP address from a VIF attached to a port or a porgroup. When a volume connector was designed initially, nova associates a MAC address with a VIF. Then, there is a type 'mac' for volume connector to retrieve VIFs with a MAC address. Now that API for attaching and detaching VIF was introduced, we can get a VIF for a volume connector by associating the volume connector with the port or the portgorup.
I don't think this requires a spec, and it seems strait forward enough. Partially in nova, which as I understand it has an open blueprint for, but supporting this internally would be cleaner. I'm for approving this RFE, although Hironori indicated that he would post proof of concept code soon.