IP phone or IP telephony involves the use of an existing, integrated Web network to interact between 2 or a lot of business or personal segments. The technology has replaced the previously explored PSTN or public switched phonephone network system. Calls created via IP telephony can traverse the established Internet network. IP phone technology empowers call-making via proprietary protocols like Session Initiation Protocol and Shopper Control Protocol. The system could be fitted with software-based mostly Soft-phones or special engineered-in hardware-empowered devices. With the ability of integrated analog telephony adapters, even simple telephones will be reused as IP phones. The essential parts of an analog IP phone embody:

* A system that integrates the DNS, STUN and DHCP clients.
* Signaling and RTP Stack.
* Audio and video codecs.
* Special user interface.
* Dedicated hardware fitted with a microphone, earphones, keypad, display interface, voice engine, ADC and DAC converters, Ethernet and a battery or some DC source.

IP Telephony also works along systems fitted among WiFi enabled mobile phones, PDAs and analog telephony adapters. Hardware empowered devices enable customers to use commercial VoIP or voice over Internet protocol providers over existing PSTN telephony. Today, the technology conjointly accommodates designs that have built-in GSM base stations to achieve access to remote areas where low-powered gateway transmitting otherwise becomes impossible. IP telephony flaunts fashionable options like access to:

* Caller ID.
* ID Calling.
* Automatic use of network-based directories.
* Conference calls.
* Decision transfer and hold.
* Storing user name/number in systems facilitated by different service providers.
* Weather report analysis.
* Live news.

Disadvantages of IP Telephony:

The IP telephony or decision access via VoIP is not without its own set of disadvantages. These include:

* Restricted or no use in the absence of a zealous web access. The system will not accommodate calls beyond the Native area network or LAN, unless there is an integrated, compatible PBX system in place.
* Total dependency on separate electric connectivity. Not like the PSTN phones, IP Phones and routers connect solely via mains electricity. The system isn't empowered to work via power generated from phonephone exchanges.
* Easy congestion. These networks, particularly residential web connectivity, easily succumb to congestion. The result is poor voice quality or an entire call-drop, within the midst of an emergency.
* Lapse in connectivity when exposed to high-latency connectivity. The technology will not empower internet-decision connectivity when exposed to latency induced by protocol overhead. The system also fails to perform effectively when exposed to satellite internet integration.
* Failure when integrated alongside other digital equipment. The IP telephony technology becomes redundant when different digital systems are integrated into the adopted phone line. Equipment like digital video recorders and home security systems don't integrate with VoIP.
* Difficult emergency calls. The technology becomes a challenge to surpass an emergency. VoIP uses special IP-addressed phone numbers and not regular public-service NANP phone numbers. Hence, it becomes tough for a 911 operator to identify the precise geographic location of the given IP address.
* Distorted facilitation when challenged by latency and packet-loss. The Web affiliation used by the IP telephony technology makes the integrated system inclined to broadband latency, jitter and packet-loss. The result's distorted and garbled communication thanks to transmission error.
* Exposure to Denial of Service attacks (DoS attack). IP telephony, like alternative web integrated networks, is subjected to Denial of Service break-downs if the address used is an public IP id.

IP telephony is vulnerable to attacks from viruses and hacking. The system uses a technology that is fully hooked in to the facility of integrated PCs. The resultant processor drain leads to frequent communication-quality loss and system-crash.

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