Voice over Internet Protocol (VoIP) or simply IP telephony is the new hot technology for transmitting speech across data networks like Local Area Networks (LANs). Over the years closed networks, such as LANs, have experienced an almost constant increase of clients and network traffic which sets higher requirements of the existing network infrastructure.

New applications and services such as VoIP have emerged.

There are several reasons for Voip gaining popularity:

• Telecommunications is a business with high revenues and a large customer segment.

• There are fiscal savings related to VoIP such as savings for long distance calls.

• The data network with its flexibility, constant development and openness will generate many new services