In the telecommunications field, telecommunications carriers (e.g., long distance providers) continually strive to increase the reliability of their telecommunications networks. A telecommunications network consists of a collection of network nodes interconnected via transmission lines. Traffic is transmitted on the network from one endpoint to another endpoint through a current route, which is a network path that specifies the transmission lines that interconnect the endpoints. The main path (i.e., trunk) through the network is referred to as the original route. The network nodes may serve a variety of functions such as amplifying the network traffic for transmission down the next transmission line in the route or establishing an interconnection between two transmission lines connected to the node (i.e., a switch). Unfortunately, the components (e.g., nodes and transmission lines) of the transmission network may occasionally fail. For example, a transmission line that is a buried fiber optic cable may fail as a result of being inadvertently severed by someone digging near the buried cable.
If one or more of the cables fail, massive disruption of services to a large number of network customers could result. Therefore, telecommunications carriers strive to quickly and economically route the network traffic around such failed components by establishing a "restoral" route. A restoral route is a portion of a path between the endpoints that does not include the failed component. The establishing of a restoral route generally involves: (1) detecting that a component on the current route has failed, (2) identifying the location of the component, (3) selecting a restoral route to bypass the failed component, and (4) implementing the selected restoral route. The reliability of telecommunication networks depends in large part on the ability to detect such failures and implement the restoral route with minimal impact on network customers.
Telecommunications carriers typically develop "pre-planned" restoral routes that are used when various components fail. The development of such pre-planned restoral routes has several disadvantages. One disadvantage is that the amount of time needed to develop the restoral route for the network can increase exponentially with the size of the network. To develop the restoral routes, a telecommunications carrier typically collects large amounts of data relating to the telecommunications network. This data can include the topology of the network, speed of network components, and relative costs of the network components. A network analyst then analyzes the collected data and identifies the pre-planned restoral routes that would result in minimal impact on network customers both in terms of cost and service. The analyst typically needs to identify a pre-planned restoral route for each component that could possibly fail. A second disadvantage is that the pre-planned restoral routes cannot realistically take into consideration every possible combination of component failures. Thus, the pre-planned restoral routes may not be an optimal restoral route given the combination of failures that have occurred. A third disadvantage is that the pre-planned restoral routes cannot adjust to the dynamic nature of the network. The topology of a telecommunication network can be dynamic, that is components can be added, removed, and changed frequently. Therefore, these pre-planned restoral routes may fail because they were developed from outdated data. Consequently, each time the topology changes new pre-planned restoral routes may need to be developed.
Because of the disadvantages of the pre-planned restoral route, it would be desirable to identify a restoral route in real-time when a network failure is detected. In this way, the restoral route could be optimized based on the current network configuration. However, the identifying of such restoral routes in real-time has been impracticable for several reasons. First, vast amounts of information need to be culled and processed to even determine the current configuration of the network. Second, such vast amounts of information have been typically stored using database systems that provide only relatively slow access. Third, because a network can have many different types of devices with very different characteristics, the computer programs that access the data representing these characteristics can be very complex and inefficient. Moreover, if a new type of device were added to the network, then the computer programs would need to be modified to accommodate the new type of device.