For more than a century, AT&T people have managed the AT&T network to provide superior reliable service. In the early years, as AT&T extended its network, "management" meant deciding which new routes to build and which existing routes needed additional circuits.
By 1900, AT&T had developed general statistical methods to predict future demand for service between any two points on the network. These methods provided guidance for network managers, who needed to balance the cost of construction with the risk of a subscriber reaching a busy circuit.
There was little active day-to-day traffic management, nor was any really needed in an era when subscribers expected to be called back by an operator when their distant party was on the line. To an extent, these operators themselves managed the network, one call at a time, as they sought routings through other switchboards that would get the customer’s call through.
1920s: Network management begins
By the 1920s, AT&T had designed its network to meet the demands for quick, efficient service at the peak periods of a normal business day. But unusual events, such as holidays and natural disasters, could cause delays. Handling these events required active, coordinated management of the network as a whole.
Long Distance operators, Kansas City, Missouri, 1920. The supervisor is on roller skates so she can get around the large room more quickly to assist the operators.
Active network management began in the mid-1920s with the establishment of regional Traffic Control Bureaus in Chicago, Cleveland and New York. These bureaus served as clearinghouses for all information affecting traffic over their portion of the network. The bureaus stayed in contact with each other and with important switching centers in their regions via dedicated teletype (printing telegraph) systems. Their staffs implemented plans for coping with unusual calling patterns, weather, damaged lines or other emergency situations. Switching centers might be instructed to reroute calls. Circuits might be temporarily reassigned. Large, manually operated wall displays provided a visual depiction of the condition of major network routes. The bureaus closed in the late 1950s.
1960s: Network Control Center
AT&T opened a Network Control Center in New York in 1962. By now, most customers dialed their own long distance calls. Switch and route information flowed in real time from the most important toll switches to status boards in New York. Similar data from the rest of the switches flowed into three new regional centers in Chicago, Rockdale, Ga., and White Plains, N.Y. Network managers could respond more quickly to unusual situations, and instruct the relevant switching centers to take steps, such as heading off calls with little chance of completion, or sending calls over indirect alternate routes with available circuits.
The Cuban Missile crisis of October 1962 provided an early test for the new centers. As President Kennedy addressed the nation, AT&T network managers placed controls throughout the network to prevent the volume of Miami-bound call attempts from overwhelming switches and circuits throughout the Southeast.
1970s: Network Operations Center
AT&T Network Operations Center, Bedminster, N.J., 1987.
In 1977, AT&T replaced the Control Center with a Network Operations Center (NOC) in Bedminster, N.J. The new center included domestic and international status boards, which automatically updated every 12 seconds, and computer databases to instantly provide managers with the information needed to reroute calls.
Many changes followed over the next decade. Dramatically increased computer intelligence became available, both in the network itself and in auxiliary functions. Common channel signaling put call-set-up on a digital network separate from the circuits that carried the calls. The network moved from analog toward digital technologies. One effect of these changes was an increased ability to actively manage the network — both automatically and by management intervention.
1980s: Updating the NOC
AT&T revamped and modernized the NOC in 1987, adding a 75-screen video wall where computer-driven support systems provided information on multiple layers and categories of network activity. Managers used computer systems and terminals to find detailed information on any switch or route in the network. They then used those same systems to issue instructions to any place in the network.
Global Network Operations Center
AT&T’s system had become a Worldwide Intelligent Network. Two regional control centers, in Denver and Conyers, Ga., opened in 1991, and assumed the task of monitoring and managing the flow of traffic onto and off of the network.
In 1999, AT&T replaced the NOC with a new Global Network Operations Center, to better to meet the needs of the 21st century.