, whilst Europe and the rest of the world uses OSI protocols. This is not strictly true since TCP/IP is widely supported world-wide, for use Note: M=Mandatory O=Optional within local and wide area networks. TCP/IP was devised by the US Defence Advanced Research Projects Agency (DARPA), in the late 1970s, as the transport Standard interfaces are also defined in the TMN physical archi- mechanism for use in the Arpanet research network. tecture, corresponding to the reference points of Figure 16.20. The The Arpanet network developed into the Internet programme, Q interface is applied at the q reference points, and for flexibility which is the largest collection of heterogeneous networks in the there are sub-classes for the Q interfaces. Qx connects MDs to MDs, world, consisting of over five thousand interconnected networks NEs to MDs, QAs to MDs, and NEs to NEs when one or both NE with several million potential users. It is administered by the Inter- includes a mediation device. net Activities Board (IAB) and is primarily associated with the Table 16.3 Relationship of TMN to the TMN building blocks Notes: (1) An MD must always have a Qx interface to be part of the TMN. (2) At least one of the interfaces inside the boxes must be present. 16/20 Network management National Science Foundation and the US Department of Defence CMOT, the Common Management Information Protocol over (known as Internet). It has a mix of local area networks (LAN) and TCP/IP. wide area networks (WAN) all operating as a single network using The IAB published three RFCs (Request for Comment) in August TCP/IP. 1988 to define SNMP. These were RFC 1065, Structure of Manage- Internet Protocol is equivalent to layer three, the network layer, of ment Information; RFC 1066, Management Information Base; and the OSI model, and TCP is equivalent to layer 4, the transport layer. RFC 1067, Simple Network Management Protocol. In June 1989 an Alongside TCP exists an alternative level 4 protocol, the User ad hoc meeting of the IAB was called to discuss the pres