VoIP Fundamentals
Voice over IP is also known as VoIP. You might also hear VoIP referred to as IP
Telephony. Both terms refer to sending voice across an IP network. However, the primary
distinction revolves around the endpoints in use. For example, in a VoIP network, traditional
analog or digital circuits connect into an IP network, typically through some sort
of gateway. However, an IP telephony environment contains endpoints that natively communicate
using IP. Be aware that much of the literature on the subject, including this
book, might use these terms interchangeably.
VoIP routes voice conversations over IP-based networks, including the Internet. VoIP has
made it possible for businesses to realize cost savings by utilizing their existing IP network
to carry voice and data, especially where businesses have underutilized network
capacity that can carry VoIP at no additional cost. This section introduces VoIP, the
required components in VoIP networks, currently available VoIP signaling protocols,
VoIP service issues, and media transmission protocols.