Node Manager has concept of VLAN/VNET. Is this anyhow related to VLAN Q-tagging in infrastructure?
Yes, this is related to VLAN tagging in infrastructure. The HP SDN Controller maintains an ARP table per Vlan Id. This table contains Ip Address, Mac Address and Vlan Id. In HP SDN Controller version 1.0 we had a MAC-table per device and MAC+VLANID as the key to access this table. However this will be discontinued in the initial release of the HP SDN Controller version 2.0.