Operations and Maintenance 2

Large computer systems consist of many parts, only some of which contribute directly to the application for which the system was built. This collection of patterns describes several capabilities of a system that perform this background, supporting role. The roles of these patterns is to aid in application specific data, performance and health measurements, managing faults, and also managing the entire system complex remotely. The patterns here, as well as others previously workshopped at other conferences, combine to form a pattern language describing a small telecommunications switch. Previous patterns have discussed the call processing application and other portions of the system's supporting capabilities. There is a partitioning of functionality within any complex computer system of two main parts: one that performs the application for which the system was built, and the other one that is not directly involved with that application but that support the application functions. The patterns here address some of the important things that are not directly involved with the application functions. These patterns are part of a larger collection of patterns that describe the architecture of a telephone switching system. Call Processing [6] introduced the main application component of a telephone switching system, the HALF CALL. This is the pattern that handles the details of the telephone or data connection to exchange information between two parties to the call. To conserve resources are shared and switched in real-time to provide the needed connection. This switching function makes a logical electronic path in a circuit switching system, or directs a packet between specific ports. Defining the application architecture is important to guarantee that the system will meet the needs of its users. Equally important is the design of the supporting infrastructure. In many systems while the application is the glamorous part of the system, the supporting functions actually make up a majority of the system. The patterns in [7] describe several functions that are necessary to switch telephone calls, but which are not actually involved in seeing that a particular telephone connection or call is made. The patterns documented here continue and expand these supporting functions. The following figure sketches out the relationship between the patterns presented here and those found in Call Processing [6] and OAM-1 [7].