Voice over Internet Protocol, also called VoIP, IP Telephony, Internet telephony, Broadband telephony, Broadband Phone and Voice over Broadband is the routing of voice conversations over the Internet or through any other IP-based network. It is the product of the Network Voice Protocol in 1973, that was originally invented by ARPANET. Recently VoIP is catching spread on the consumer and commercial market advertising decreased costs and wider market acceptance. VoIP to VoIP calls are often free, while VoIP calls to PSTN( Public Switched Telephone Network) which usually has an additional cost to the VoIP user. There are two types of PSTN to VoIP: Direct Inward Dialing and access numbers. DID connects to the caller directly to the VoIP client. Access numbers require the caller to input the extension number of the VoIP user. Its integration into telecommunications has gone smoothly, but there are challenges in its use. Often when satellite circuits are involved in telecommunications latency is a huge problem. Making sure that packets arrive in the correct order and consistently happens to be VoIP's biggest challenge. Traditional telecommunications via conventional phones are connected directly to telephone company lines. If there is a power outage, the lines are kept operating by backup generators and batteries. Service is maintained if the telephone at the consumers residence has a built in battery which sends and receives the signal. This technology is getting rarer and rarer in modern day telephones, but for VoIP it is non-existent. The modems required for the broadband connection require a UPS or a generator to function. Perhaps there isn't a power outage and the broadband provider is temporarily knocked out. How will that affect their customers or the company at hand? PSTN is very reliable in comparison to broadband networks which have really only been mainstream for ten years and even the best can have service disruptions. On networks that have lots of traffic or the calls are going over long distances there will be moments where there will be a momentary dropout in voice. Emergency calls are very hard to establish a location, therefore being sometimes a danger to the public according to some. Other than busy network problems, sending faxes over VoIP is still very painful. Much of the problems found by VoIP users sending faxes are not linked to anything explainable nor are they sometimes specific enough to trouble shoot. In this writer's experience, the company who employed myself was having intermittent VoIP fax issues which couldn't be explained through tech support. It turns out that even the the connection was capable of typical faxing speeds, the solution to the problem was slowing the connection. Concerning scalability for an emerging company, most broadband connections have enough extra bandwidth to make adding that extra “telephone” line easy and cheap. Moreover that it can make establishing a centralized call center. For a lot of users VoIP only complements PSTN services the consumer/company already uses. For corporate environments, they have dedicated IP networks in place to connect switching stations for the required quality service levels the desire. For consumers, VoIP phones are cheap and are often billed by monthly rates not by minutes. They can be an attractive solution for home and small business use an acceptable if not likely alternative to traditional phone services. They can be expanded easily as companies grow, however, security and usage concerns with their adoption will soon surface in the mainstream. References http://www.securityfocus.com/infocus/1767 http://www.fcc.gov/voip/