In addition, the VNS system architecture is designed to provide scalability for small to very large IGX networks. Euro ISDN public networks is also supported. The VNS system has a semidistributed architecture and is typically connected to one IGX 8400 series node with network connections from numerous other IGX nodes. Additional VNS systems can be added to the network, based on geographic, quantitative, or network load requirements.
Semidistributed systems have several advantages over imbedded systems.
Enhancements and improvements to the signaling protocol code and development and deployment of new features can be accomplished quickly, with no impact to the network. Only a few network elements are affected during an upgrade with a semidistributed system, compared to an upgrade with an imbedded system, which affects every node processor. Each network element is optimized for specific tasks and does not place a burden on the processor for another unit. The VNS system hardware is fully redundant, consisting of two identical units that are configured to perform as a redundant pair. The carrier-class reliability of the IGX system provides further resiliency for the network.