This object indicates whether the IP address reported alongside it (in hh3cNMIpAddress) is an IPv4 or IPv6 address, tagging the format of that interface's address. It is included in SNMP notifications sent by the device so a network management station knows how to correctly parse the accompanying address value. For instance, a value of ipv4(1) tells the NMS to interpret the paired hh3cNMIpAddress as a standard dotted-decimal address rather than an IPv6 address.