It is the web innovation to convey  voice correspondence and mixed media sessions over Web convention systems, for example, web.

The steps included in starting voip phone call are flagging and media channel setup,digitization of the simple voice sign, encoding ,packetization and Transmission as Web convention parcels over a parcel exchanged system.

             Voip frameworks utilize session control  conventions to control the set-up and tear-down of calls.There are three sorts of  Voip devices that are ordinarily utilized, IP telephones, Softphone and Versatile Softphone.

IP Telephones: IP Telephones are the most institutionally settled yet at the same time the slightest clear of the VOIP devices

Softphones: It's utilization has expanded amid the worldwide subsidence the same number of persons, searching for approaches to slice expenses have swung to these instruments for nothing or economical calling or feature conferencing applications.

Three classes of programming IP: Web calling,voice and feature texting and web conferencing.

Versatile Softphone: It is only one more illustration of the flexibility of voip. Voip is accessible on may advanced mobile phones and web  gadgets.

Voip  has been executed in different ways utilizing both restrictive and open conventions and measures.


Ø  H.323

Ø  Ip sight and sound subsysem (IMS)

Ø  Media Portal Control Convention (MGCP)

Ø  Session Start convention (Taste)

Ø  Ongoing transport protocal  (RTP)

Ø  Session Portrayal Convention (SDP)

The H.323 convention was one of the, first viop convention that discovered broad usage for long-separation movement and in addition neighborhood systems. Since improvement of more current, less complex conventions ,, for example, MGCP and Taste. The taste has increased broad voip market infiltration.

•  IETF Standard: Taste, Mgcp .

•  ITU Standard : H.323 ,Megaco .

•  Proprietory : IAX(Internation Asterix) , Sccp(Cisco) .

Taste and H.323 are flagging conventions.

Mgcp and Megaco are Media Door convention

Voip Focal points:

1) Shabby calls or Free calls.

2) Low Gear Cost .
3) Voice,Data,Video and cable,Iptv.
4) Qos (Nature of administration).

Voip Dis-Favorable circumstances:

1)  Bandwidth

2)  Electric Power   

Voip Protocol Layers: