Industry Terminology

INTERNET PROTOCOL: The "IP" in voice over IP. It's one of a large family of specifications that define the transmission of information over data networks. But this one is particularly critical because it tracks the Internet addresses of nodes, routes outgoing messages, and recognizes incoming messages. It's the backbone -- or more figuratively, the language -- of the Internet.

VOICE OVER IP: The technology used to transmit voice conversations over a data network using the Internet Protocol described above. The data network involved might be the Internet itself, or a corporate intranet, or managed networks used by local or long distance carriers and ISPs. Who runs the network doesn't matter -- what does is the fact that you're taking voice (i.e., analog information) and encoding it digitally, converting it into packets, and then using a data network to move those packets along the most efficient path to their destination, where they get reassembled and delivered in the format they started in: voice.

IP TELEPHONY: A term used largely interchangeably with Voice over IP and VoIP to describe the transmission of voice -- in this case referring more specifically to voice in the form of live calls, rather than messages -- over data networks.

LATENCY: The average "travel" time it takes for a packet to pass through a network. The lower the latency, the better the voice quality.

PSTN: The public switched telephone network that traditionally routes voice calls from one location to another. The UN-VOIP.

FXO: Foreign Exchange Office - the interface on a VOIP device for connecting to an analog PBX extension.

LAN: Local Area Network

WAN: Wide Area Network

TOS: Type Of Service

ISP: Internet Service Provider

RTP: Real Time Protocol

RSVP: Resource Reservation Protocol

QoS: Quality of Service