The Cisco Network Route Director (NRD) is a high-performance Session Initiation Protocol (SIP) route proxy for intercarrier, inter-call management server (CMS), and on-net or off-net routing. It is typically a centralized function in the communications network. It can be deployed in multiple points of presence (POPs) and is usually deployed as a cluster of servers for scalability and high availability.
The Cisco NRD can receive route requests from any SIP server in the network. It forwards SIP requests to other SIP-based applications or networks or routes the request to other SIP-based applications or networks. Typical SIP interactions include those with:
The Cisco NRD is intended to support IP multimedia subsystem (IMS) as the Cisco implementation of the interrogating call session control function (I-CSCF) and breakout gateway control function (BGCF).