As mentioned before, the protocols and standards used for IP Telephony are open and publicly available.This allows research institutions to work on their own services and solutions.
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[IP Telephony Cookbook] / Introduction
It is important to point out that before introducing IP Telephony into the network of an organisation; several issues unknown to the old telephone system have to be taken into account.
A rough, non-exhaustive list may include addressing (special subnet/VLAN for phones), Quality of Service (QoS), security, positioning of gateways, interfacing of firewalls and, last but not least, maintenance of the system (backups, spares, etc., - something not very common in the legacy PBX world).
With regard to the economic aspects, the ‘packetisation’ of voice using Voice over IP has given rise to new international telecommunications carriers.These carriers have distributed network architectures using the Internet as a platform.VoIP networks have an architecture offering the most efficient way to implement multilateral telecommunications agreements, thus eliminating the need for carriers to engage in hundreds of bilateral traffic agreements as are required between traditional circuit-switched PSTN carriers. Moreover, since packet networks are software driven, they can be configured more dynamically than traditional PSTN networks. For example, with a global voice over packet network, new destinations are available to all users on the network, without the need for constant additional investment.
IP Telephony telecommunications companies may expand the availability of services to a wider audience. IP Telephony technologies can be used to build voice networks more rapidly and at a lower cost than legacy PSTN systems. Easier deployment of Voice over IP networks can bring the benefits of telecommunications to more people in a much shorter timeframe than would be possible with conventional PSTN networks. At the same time, not having to build extensive infrastructure provides the motivation for many companies to migrate to IP Telephony architectures.
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[IP Telephony Cookbook] / Technological Background
Technological Background }