1. Voice over Internet Protocol (VoIP) phone services Voice over Internet Protocol (VoIP) is a technology that allows you to make voice calls using a broadband Internet connection rather than regular phone line. The steps involved in originating VoIP calls are similar to traditional digital telephony. The only difference is that instead of being transmitted over circuit-switched- network, the digital information is packetized and transmitted as IP-packets over a packet-switched- network. PSTN and mobile network providers It is becoming increasingly popular for telecommunications providers to use VoIP telephony over public IP networks to connect switching networks with other telephony network providers and to interconnect these telephony network providers with each other. S?artpho?e’s and Wi- Fi enabled mobile phones may have SIP clients built into their firmware or be provided as application download. Corporate use Because of bandwidth efficiency and low costs many businesses are migrating from traditional copper-wire telephone systems to VoIP systems to reduce their monthly bills. VoIP allows both voice and data communications over a single network, which reduces the significant infrastructure cost. The VoIP devices have simple user interfaces, so users can easily make simple system configuration changes. Types of VoIP phone services The VoIP services can be classified into four types: Peer to peer: The communication is done using internet only, calls do not use the traditional telephone network, the Public Switched Telephone Network (PSTN). VoIP out: It is a service where calls can be made from the VoIP network to PSTN. VoIP in: it is a service where the calls can be made from a PSTN to a VoIP network using a telephone number. Two-way: it is a service that allows the calls do be made both ways between the VoIP network service and PSTN service using telephone numbers.

2. Advantages of VoIP phone services Low cost: This technology provides large financial savings. It happens because, there exists only one network carrying the voice and data of only one supplier. Portability: The main feature of VoIP is that unlike the traditional telephonic services it is dista??e a?d lo?atio? i?depe?de?t. You ?a? ?e ?alli?g ???? ?iles away a?d it does?’t make any difference in terms of connectivity and cost. Disadvantages of VoIP phone services Emergency calls: Traditional phone equipments can trace your location. However, because a VoIP call is transfer of data between two IP addresses and not physical addresses there is no way of determining where your VoIP call is originating from. Security: The most prominent security issues of VoIP calling are identity and service theft, viruses and malware, denial of service, spamming and phishing attacks. All these disadvantages will be overcome in time. There is a lot of work being done to increase the reliability and usefulness of VoIP phone services.