tion. Other required skills include database administration, systems administration, load balancing, the ability to develop and maintain a technical architecture, and LAN/WAN and network connectivity and other general IT skills. 3.3 Application Support In general, there are three levels of application support, which are identified as tiers 1, 2 and 3. Each tier is associated with certain roles, skills, costs, and numbers of personnel. Chapter 7 - Supporting the Life of an OSS Integrated Platform Tier 1 Support. This is typically a general help desk for internal resources for all IT-related questions and issues. The help desk will field all types of calls, from users having problems with e-mail, to noticeable latency in applications, true bugs in applications and applications that greatly impact operational effectiveness off-line. The typical staff level for a tier 1 support team is about one support person for every 100 to 150 users. Tier 2 Support. Staffing levels depend on an application's complexity, its configuration and how quickly the business changes. Typically an IIC will require two to five configuration and application experts per application to maintain the configuration, product catalog and business rules. Keep in mind that these are higher paid, knowledgeable, more experienced people. In addition, EAI engineers may be required to maintain integration software and business rules. System administrators and database administrators are also required to handle IT issues across the applications, such as back-ups, restores and security. Tier 2 support personnel can assist in upgrades and new releases that impact operations minimally. For large- scale upgrades, the applications development group will likely take the lead. Tier 3 Support. For packaged applications, the vendor generally manages tier 3 under a formal maintenance agreement. Most vendors charge between 15% and 22% of the license fees for maintenance. For in- house applications, tier 3 must be managed with internal resources, which can represent a