OSF or MF through a data network within a TMN which supports the Data Communication communication network it is included within TMN, whilst direct Function (DCF). It consists of the dedicated communications paths, connections of WSF to OSF or NEF is not included within TMN. such as X.25 and voice channels. The X interface is applied to the X reference point. The purpose of The network element (NE) is made up of the telecommunication the X interface is to interconnect two management systems or equipment, groups of equipment or parts of equipment. It sup- TMNs. These TMNs may belong to separate administrations or to ports any item which performs NEFs and has one or more standard an administration and a private service provider. Q-type interfaces. Equipment which does not have this standard Table 16.3 shows the possible interfaces which each TMN build- interface needs to connect to the TMN via a Q Interface Adapter, as ing block can support. It is based on Table 16.2, i.e. the functional above, which converts between the non-standard and standard man- blocks associated with each building block. agement interfaces. The Work Station (WS) is the system which performs the WSFs, these latter translating the information from the f reference point to a suitable format for the user at the g reference point and vice-versa. 16.9 The Simple Network Management Protocol The relationship between the TMN building block names and the TMN functional blocks is shown in Table 16.2. The Simple Network Management Protocol (SNMP) is widely used Table 16.2 Relationship of the TMN building block names to manage networks which employ the Transport Control Protocol to the TMN functional blocks and Internet Protocol (TCP/IP) as the transport mechanism. These protocols are reviewed in this section and compared with those based on OSI. 16.9.1 The TCP/IP The Transport Control Protocol and the Internet Protocol have their origins in the USA, and unfortunately they are therefore considered to be protocols which are primarily intended for use there