f a point-to-point fiber optic route is severed, for example, all elements serving that route will report a failure. The NMS can correlate the alarms and determine that the alarms coming from the optical layer are the source of the alarm deluge. Some NMSs can also route trouble tickets automatically to the technicians or engineers most qualified to fix specific problems. Further, integrating NMSs with provisioning and inventory systems can allow an IIC to determine exactly which customers are affected by a network outage SO they can be contacted proactively. The Ultimate Guide to Building and Delivering OSS/BSS Network Notify Trouble Ticket Affected Configuration Record Customers SLA Manager Monitors performance Check against Receives and correlates alarms contract Adjustment Customer giving Failed Customer Facility Customer Circuit Customer Customer SWITCHING CENTER Customer Customer Customer Customer Figure 4. NMS and Trouble Management Network elements can not only report basic alarms, but quite often they can report the exact problem they experience, such as a specific card or port that is troublesome, but has not actually failed yet. They can also provide statistics about the number of blocked calls because of traffic overflow. A prevalent issue in recent years is caused by dial-up Internet connections. These can tie up switching resources for hours, skewing traditional IIC line ratios (one line for 10 subscribers) which can cause increased congestion. The switch can identify where the calls originate, where they terminate and what is the average "on-line" time. IICs use this information to determine the best place to install dial-up, off load solutions in the form of packet switches that redirect dial-up traffic destined for the Internet before reaching a voice switch. Network management systems also provide predictive analysis functions critical to network design, build out and failure avoidance. Traffic tends to grow in patterns that the NMS can analyze to determine where new network resources are best de