Voice over IP is a set of protocols that allows you to perform
telephony voice communications over a standard Ethernet IP network instead
of over dedicated switched telephony voice channels and trunk circuits using
ISDN or channel associated signaling.
The advantages of using an IP network to carry telephone conversations
are:
- Standard computer equipment and networking hardware can be used for the
network and endpoints. This is usually much cheaper than conventional telephony
hardware and occupies less physical space.
- A single network can be used for both data and voice transfer.
- The network capacity for handling voice can be increased at peak call
times by controlling the volume of data transfer. When call volume is low,
the excess bandwidth can be used for data.
- It is easier to create applications that integrate data with voice when
the same network is used for both.
- New telephony features can be quickly deployed as they are implemented
in the network endpoints rather than within the network itself.
- Techniques can be used to compress the voice data and suppress the sending
of voice data during periods of silence; this enables much more efficient
usage of the network and lower call costs.
The disadvantages are:
- Network bandwidth must be carefully managed to avoid voice quality problems.
- Voice packets may take longer to get across the network than if the same
data were to be sent over a circuit switched connection, resulting in longer
delays for your voice applications.