ering Committee (NRSC), which is made up of representatives from nationwide wireline and wireless providers. The committee looks for patterns by type of failure SO that they can determine ways to prevent them. Planning to Insure Reliability and Sustainability Carrier networks are now largely IP-based, converged networks, wherein a single network infrastructure carries data as well as telephone traffic. Thus, outages cause disruptions to businesses, governments, and consumers. In addition, traffic volume increases significantly in emergencies. During widespread emergencies, mobile carriers free up capacity for the additional volume required by assigning less frequency to each call. Thus, more calls can be carried, although at lower sound quality. They can also quickly set up portable cell sites and additional generators at towers or mobile switches that lose power. This enables mobile providers to restore service to these areas. In addition, if one part of the country is hit by a natural disaster, other carriers will send staff members and equipment to assist in restoring service. Carriers plan for emergencies in various ways. For example, they build backup wireless routes between critical switches and public safety answering points (PSAPs) for E-911 calls. They also look at ways to increase security against hackers and terrorists at peering sites where carriers exchange IP traffic. In addition, providers consider methods to avoid user errors. User errors occur most often during network upgrades and programming changes. FirstNet-A National Public Safety Network www.TechnicalPDF.com In the days and hours immediately after the 9/11/2001 terrorist attacks on the World Trade Center's Twin Towers in New York City and the Pentagon in Washington DC, firefighters, police, and other first responders found that because of incompatible mobile devices they could not communicate with first responders from other municipalities. This inability to coordinate strategy acted as a heads-up for the need to be able to communicate with