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is a IETF standard  and it uses TCP/IP standards. using this standard multimedia conferences are held. The main usage of this protocal is to create modify and terminate the session.

    VOIP with SIP standard is same as HTTP. The transaction made here is simple to understand first request was sent by the client to server in the form of packet and the server send an acknowledgement to the client based on the acknowledgement the connection wil be established.

VOIPÂ  CODINGÂ  SCHEMES:Â  There are mainly two types of coding schemes

1.Speech Coding Schemes:
Again in this there are three different coding schemes (a)waveform coding (b)scheme, source coding scheme (c)hybrid coding scheme.

(a)Waveform coding scheme: This scheme requires more bandwidth and it is used only in high qality transfers.

(b) Scheme source coding scheme Here the voice signal is compared with mathematical code that is generated within the protocol and then it mapped and sent. The transmission of the data is done by sending low bit rates. It uses low bandwidth for transmisson

(c)Hybrid codecs: The output is the best among all the coders/decoders. The technique used in this one is production model of sound.

(2) Voice Encoder Schemes:
There are large bnumber of voice encoding schemes some of them are G.711, G.711a G.728, G.729

Now by using the opnet let us see how the performance of the VoIP varies based on the voice packet size and the speech activity detection

DISCRIPTION OF WORK DONE:
In the opnet let us voice project where the we are having the two of routers and four clients and they are connected to the routers in an horizontal manner. Here two clients of  different priority are connected on the one end with the router and the remaining two are connected to the other end of the another router. The lan we are using is of the low priority ones we can see this in figure below

Now we are going to edit attributes where we are using the G.711 encoder scheme and now am going to  give two different value for the voice frames per packet and am going to compare them here the type of srevice we are using is  excellent effort(3) and in this type we are goig to diable the speech activity recognition

I am taking 900 seconds of time to run the simulation at a seed value 128 the voice coding rate is 64Kbps and packet size is 1milli second

Graph for VOICE PACKET DELAY VARIATION for the ONE VOICE FRAME PER PACKET AND TEN VOICE FRAMES PER PACKET  

VOICE PACKET DELAY VARIATION FOR  TEN VOICE FRAMES PER PACKET  

VOICE PACKET DELAY VARIATION ONE VOICE FRAME PER PACKET

SIMULATIONÂ Â Â Â  TIME VOICE FRAME PER PACKET AVERAGE VALUES OBTAINED FROM GRAPH
900 seconds

1

  0.74153

900 seconds

10

  0.00001

GRAPH FOR VOICE PACKET END-END DELAY  FOR THE ONE VOICE FRAME PER PACKET AND TEN VOICE FRAMES PER PACKET  
VOICE PACKET END-END DELAY  FOR  TEN VOICE FRAMES PER PACKET  
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