Voice Over Internet Protocol (VoIP)


What is VoIP?

VoIP is an acronym for Voice Over Internet Protocol. It is the voice service over the internet. Now in the days of fast internet VoIP is taking over the telecom industries. It is changing the way people communicate with each other. It is changing the complete infrastructure of phone calls by making them so cheap, also their is no any reduction in the quality of the calls. 
Voice Over IP can drive through any IP network, including those connected to the internet such as Local Area Networks (LANs).

Remember, their is difference between Voice over IP and Telephony over IP.
  • Voice over IP is a set of standards devices and protocols which enables Voice Over IP Protocol.
  • Telephony over IP, is a phone service and is available to the public but made with VoIP technology.
VoIP phones are also known as IP phones. In VoIP phones the calls are placed over the internet instead of Public Switch Telephone Network (PSTN). 

Working procedure of VoIP phone

Power Supply

Different VoIP Phones require a different way of power supply. Some VoIP phones require AC adapters but some work using the Power over Ethernet (PoE). The PoE supply phones does not require extra power and data cables, these phones just need the ethernet cables for complete working.

IP Assignment

For the assignment of IP addresses to the VoIP phones various networking components are required. Firstly the Dynamic Host Configuration Protocol is used to assign the IP addresses to the phones and then the Domain Name System tracks the IP addresses of the other phone that is need to be contacted. Then the two phones are able to communicate with each other. 

Protocols used

VoIP phones require a number of protocols to setup a communication medium between two entities. But the most common protocol that is used is "H.323". This protocol is the standard approved by the International Telecommunication Union (ITU). Now this protocol is the standard for interoperability of Audio, Video, and Data transmission. This protocol also manages the bandwidth between two communication entities. If their is less bandwidth available then it will reduce the quality of the service but it will not stop the communication. 

The Second protocol that is used in VoIP communication is Session Initiation Protocol (SIP). This protocol is responsible for the connection management of the two communicating entities. It is a signalling protocol used for setting-up the session, maintaining the session and terminating the session, including audio, video and messaging applications. 

The third protocol is Media Gateway Control Protocol (MGCP). It is responsible for controlling media gateways on internet protocol networks connected to the public switch telephone network (PSTN). MGCP recognizes three essential elements of communication, the media gateway controller (call agent), the media gateway endpoint, and connection between these entities. A media gateway may host multiple endpoints and each endpoint should be able to engage in multiple connections. Multiple connections on the endpoints support calling features such as call waiting and three-way calling.

Advantages and Disadvantages of VoIP phones

Advantages

  • VoIP phones reduce the calling expenses of the organisation. While traditional analog phones have lower upfront cost but they have much more expensive calling rates hence increasing the company expenditure. 
  • VoIP phones offer great mobility and scalability than traditional analog phones. If any organisation changes their physical location then their is no need to acquire new phone lines unlike the traditional analog phones, which requires to have the complete new phone lines. 
  • VoIP phones can also integrate with third party communication applications like any Customer Relationship Management software (CRM). This leads the organisation to keep the call records with unique caller ID.

Disadvantages

  • As VoIP phones communicates over the internet, they need a reliable internet connection and high bandwidth. If their is low bandwidth present then communication will not be proper and  will experience latency problems. This will result in delays, and the phone calls may be dropped in between.
  • VoIP phones do not support emergency calling features like the Police, Ambulance etc.

 



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