In the world of bits and bytes the shortest distance between point A and point B is not a straight line but it is determined by another series of factors known as routing metrics that are a kind of scales that is decided that route must be followed at each time to reach the destination. The congeston of routes, distance, the transmission delay and the number of jumps are some employed metrics. As voice transmission does not require that he reserves a physical channel on an exclusive basis many more services are possible through a network that uses VOIP to make phone calls and videoconferences. Some advantages of ip telephony to the small and medium company that has a LAN local area network, you would be very useful and economical to be able to use the existing local network with VOIP technology for all internal calls avoiding having to hire extra services such as redirection of calls, caller ID or other services to the telephone service provider company. The small to medium enterprise you may designate a computer in the Organization to fulfil the role of PBX(Private Branch Exchange) or switchboard with the help of specialized software for this purpose such as Asterisk, (a package of software for open source with which you can manage a wide range of VOIP services) and with the acquisition some hardware components that would serve to adapt the analog telephones to VOIP technology or to replace the analog phones by ip phones or simply software phones are installed on each of the workstations and replaced regular phones by computers, headphones, microphones and the virtual phones. Then you can hire a VOIP gateway service to connect with the outside world and to be able to make calls at low cost. Where the undertaking has several sites can implement the solution so that all calls made between venues do not have satisfied either.