The document provides details about a proposed IP telephony solution for Steel Authority of India consisting of server-based call processing with redundancy and various media gateways. The solution includes three call server stacks for redundancy between the main plant exchange building and backup admin building. It also describes local survivability at remote sites using a passive communication server if the link to the main call servers fails. The solution supports various TDM interfaces and services integrated with the call servers like voice mail, conferencing, and a complaint logging IVR system. Management is provided through an NMS for configuration, alarms, and call billing.