communication network (X.25, FR, or IP), running the AF on available transport layers (UDP or TCP in IP networks). This implies that traffic system nodes and management system nodes will be nodes of different switching networks. If the traffic system includes a suitable packet-switching strata, it will most likely be also used as the stratum in mpCP network interfaces. This is how OMAP operates in an ISDN and how management planes are realized for IP, X.25, and FR traffic systems. Note that this implies that traffic system nodes and management system nodes will all be nodes of same switching network (which can have severe consequences if that network goes down). In AMLn we identify the needs of abstract protocol operations for mpCPs and provide alternative usages of the AMLn-SAGM. How to realize the network inter- face between traffic and management systems is the choice of the designers of a network system for management, however. Since most of the existing management concepts are not built on the actor-agent separation and LSM-LPM separation principles, we will briefly discuss their connectivity solutions here. The TMN solution CMIS/CMIP is based on the fact that the connectivity stra- tum is an OSI RM stratum, which unfortunately creates a very complicated struc- ture and set of specifications. This structure is depicted in Fig. 5.7. 5.3 The Management Plane Control Point (mpCP) Traffic system layer mpCP network element and resources (R) AF-CMIS interface CMIS spec. ROSE spec Application layer CMISE CMIP spec. element ROPM spec ACSE spec ACPM spec "Presentation Presentation layer) connection" element Session layer element Traffic Management OSI layer 4 system system Fig. 5.7 The mpCP connectivity stratum in TMN (note: this is not an AMLn model). ACPM=association control protocol machine; ACSE=association control service element; CMIS=common management information service; CMISE=CMIS element; CMIP=common management information protocol; FTAM=file transfer, access and management; ROPM=remote operations protocol 