Voice over IP refers to technology that transmits live voice communications across a network connection using IP protocols. A key benefit of Voice over IP is its capability to help reduce expenses because phone calls travel across the data network rather than the phone company's services. IP telephony encompasses the entire range of VoIP related services such as the interconnection of phone sets for communications; associated services such as invoicing and dialing plans; and basic features including group calls, transfer, forward, and hold. These features might previously handled by a Private Branch Exchange (PBX).
Voice over IP is the basis for more advanced unified communications solutions. Cisco's Unified Communications system of voice, image, mobility, and Internet Protocol communications offerings provides the tools for creating a single converged network that can handle multiple types of traffic concurrently. Cisco's solution provides this functionality while sustaining a high level of network resilience, Quality of Service, and Protection.