, the manageable characteris- tics of each device in the network are defined at this functional layer. The element management layer manages the characteristics of the elements defined by the network element layer. Information found here includes activity log data for each element. This layer houses the actual Figure 3-69 The TMN Business Management layered model Service Management Network Management Element Management Network Elements Downloaded from Digital Engineering Library @ McGraw-Hill (www.digitalengineeringlibrary.com) Copyright © 2004 The McGraw-Hill Companies. All rights reserved. Any use is subject to the Terms of Use as given at the website. Telephony Chapter 3 element management systems responsible for the management of each device or set of devices in the network. The network management layer has the ability to monitor the entire network based upon information provided by the element management layer. The services management layer responds to information provided by the network management layer to deliver such service functions as accounting, provisioning, fault management, configuration, and security services. Finally, the business management layer manages the applications and processes that provide strategic business planning and tracking of cus- tomer interaction vehicles such as SLAs. OSI, while highly capable, has long been considered less efficient than IETF management standards, and in 1991, market forces began to affect a shift. That year, the Object Management Group was founded by a num- ber of computer companies-including Sun, Hewlett-Packard, and 3Com -and together they introduced the Common Object Request Broker Architecture (CORBA). CORBA is designed to be vendor independent and built around object-oriented applications. It allows disparate appli- cations to communicate with each other, regardless of physical location or vendor. And while CORBA did not achieve immediate success, it has now been widely accepted, resulting in CORBA-based development efforts among network management system