TCP/IP Tutorial and Technical Overview - IBM Redbooks

large-scale data networks, expecting cost savings and reduced expenses
resulting from a merged multimedia network. Specifically:
► For the users, voice calls using the Internet are a means to reduce costs,
avoiding tolls on the PSTN (toll bypass) and long-distance voice networks.
► For a pure VoIP service provider, minimal infrastructure ownership can be
achieved by allowing the client to tap into the existing Internet service
provider access and transport.
► For cable operators, VoIP enables the reuse of the existing infrastructure
while rolling out new services.
► For network carriers, VoIP service is mainly a tool to counter the threat from
new service providers while increasing the efficiency of their own
infrastructure.
New applications provide improvements to existing telecom services. Key VoIP
applications include:
► Telecom trunk replacements by using Ethernet trunk cards VoIP Private
Branch Exchange (PBX) switches
► Toll bypass services for multinational corporations by linking offices from
different cities or countries
► Rapid application deployment, made possible by following the IT and data
networking world in combination with the use of open APIs and standards
Finally, applications and service features can be distributed throughout the
network. Traditional central office switching equipment can be replaced by less
expensive servers in handling the call processing and routing.
Chapter 20. Voice over Internet Protocol 725