Target markets
Call centres and helpdesks are seen as a big target market by VoIP vendors Ã, potentially allowing operators to see what customers can see on their screen, and to converse with and answer questions from shoppers on e-commerce sites.
There are also advantages for general telephony, especially for mobile users where VoIP will make it possible to send and retrieve a mix of voice and email messages through a single integrated mailbox. And service providers see VoIP as a way of earning extra revenue Ã, enabling them to compete against telecoms providers such as BT.
The International Telecommunication Union (ITU) H.323 standard provides a broad foundation for the transmission of voice, video and data over packet-based networks, with little or no need for infrastructure changes. Since the standard's ratification in 1998, H.323 has been widely adopted to provide interoperability between VoIP products over local and wide area networks.
Along with other standards, notably the Session Initiation Protocol (SIP) that makes it easier to translate phone numbers to IP addresses and back again, H.323 can enable VoIP solutions to work alongside traditional public switched telephone network (PSTN) networks. This would make it possible, for instance, to call an ordinary phone from a VoIP system and vice versa.
However, the very nature of IP communications presents problems that will have to be overcome before VoIP can offer reliability and quality.
A lot of work has already gone into coping with the delays on IP networks. Delays in packet transmission can result in echo and jitter effects and, in extreme cases, talker overlap. And there is actually no guarantee of packet delivery at all. On a standard IP network Ã, packets are often dropped altogether during peak loads or when a link fails. With data that is not a problem Ã,Âthe lost packets are simply re-sent Ã,Âbut with speech it is a different matter, a loss of one to two percent of the packet stream may cause unacceptable quality for a conversation. And security measures for firewalls and virtual private networks (VPNs) can bring still further delays and packet losses.
