 which has been accepted by CCITT as Recommen- dation X.200. It is important to remember that OSI deals with communications between systems and not processing within these end systems. It gives an abstract structure for the subdivision of communication functions and so forms a framework for co-ordination of current and Figure 16.7 Interaction between two proprietary networks future standards, rather than defining the standards themselves. In a at the manager level related area JTC1 is working on a second reference model, the Reference Model of Open Distributed Processing (ODP) which will Summarising, currently management systems are used primarily define the standards to enable distributed processing, i.e. the ability to control mono-services, such as a telephone network, a packet to run systems on equipment supplied by several different manufac- switch network, telex, etc. These are usually dedicated to homo- turers. geneous groups of users. In the future multi-services will be the Base OSI standards provide several options, so that the same set norm, using a mix of carrier networks, some privately owned and of standards can be applied to many different applications, and also 16/8 Network management because, to be useful, standards operate in combinations within the 16.6.1 The seven layers seven layer stack. Functional standards or profiles specify a subset of these base Figure 16.9 shows the traditional OSI seven layer model in which standards for particular applications, often adding details which are communications is taking place between two end systems, using an missing from the base standards, and it is these profiles which intermediate or relay system. The operation of this model is covered largely enable interworking between systems. Several different in more detail in Chapter 12 and is briefly reviewed here. groups are involved in defining profiles, for example the Manufac- turing Automation Protocol (MAP), and the Technical and Office The OSI concept assumes that exchanges of data between systems Proto