nformation Base (MIB) MIB is a virtual database that contains information about managed objects. The information is organized in a treelike structure by a grouping of related objects and relationship that exists between them (see Figure 5.6). A managed object instance in the tree includes attributes that serve as its relative distinguishing name (RDN). The RDN attributes are used to uniquely identify the instance among the derivatives or children of the managed object. By concatenating RDN with the MIT path from Fundamentals of EMS, NMS and OSS/BSS Manager Agent Agent Managed objects Figure 5.6 Management information base (MIB). the root to a given node, a unique distinguishing name (DN) is obtained that identi- fies the node. The node can be any information about a managed object and the DN will be used by the manager to store and query any particular information. Both agent and manager use the MIB to store and query management infor- mation. The agent MIB covers information only about the managed object it is associated with while the manager MIB covers information about all the network elements managed by the manager. While MDB is an actual physical database like Oracle or SQL, MIB is a virtual database. The MIB implementation falls under of the following three types: MIB Version I: This first version of MIB was presented in RFC 1066 and later approved as a standard in RFC 1156. MIB Version II: This version of MIB was proposed to cover more network objects as part of RFC 1158. It was later approved by the IAB (Internet Architecture Board) as a standard in RFC 1213. Vendor specific MIB: These complement the standard MIB with additional functionality required for network management of vendor specific products. This book has a chapter dedicated to the discussion of MIB considering the wide acceptance of this schema in information management. 5.4 OSI Communication Model The OSI communication model defines the way management information is exchanged between entities in a NMS (agents/managers). The transport medium,