2.1.1.2 NetBIOS over TCP/UDP (NBT) Transport

NetBIOS over TCP/UDP (NBT) is specified in [RFC1001] and [RFC1002]. NBT provides a mapping of the required NetBIOS services to the TCP and UDP internet protocols. Because the underlying IP protocol is routable, NBT transport can provide NetBIOS services across an internetwork. However, special servers are required in order to maintain the coherency of the NetBIOS name space across multiple subnets. These are the NetBIOS Name Server (NBNS) and the NetBIOS Datagram Distribution Server (NBDD).<4>