NETAL: a Simulation Environment for Network Management Systems

this document is to describe the software structure and usage of NETAL. NETAL reproduces what happens in a telecommunication system when a fault (or several faults) occurs by implementing all the models described in [1] in a fully parameterized way. NETAL is not designed to be specifically used for a particular network but allows the user to specify arbitrary network topologies and to control all timing and probability parameters that determine the behavior of the network elements (NEs) and their managers. The general NM model employed in NETAL consists of a three-tiered hierarchy. At the base of the hierarchy are the NEs that constitute the objects of the network management system. All NEs are connected to regional NE-Operating System (OS) managers. NE-OSs are at the second level of the hierarchy and keep NM information of their children in a local storage area (NE-OS-MIB). NM-managers (NM-Ms) are at the top of the hierarchy and are responsible for summarizing the information of a fairly large system of NE-OS managers. Each NE can be connected to only one NE-OS, and each NE-OS can be connected to only one NM-M. Multiple NM-Ms can manage different NM systems, and they can communicate among them. a more detailed description of this NM model is in [1]. 2 Structur