1) To understand how and why VOIP calls work, you must first
understand what a codec is and what role does it play in VOIP. Although, this may not be necessary to understand VOIP capture but it gives you insight on the working of VOIP.
As you can see, a CODEC samples audio coming into your audio device and using an algorithm converts into a digital output which can be used up in making audio files(.mp3, .m4a), understandable by the computer.
The same mechanism is followed vice versa while displaying some sound through your headphones or speakers.
2) So, VOIP consists of an RTP protocol which is responsible for carrying the audio stream. The RTP header consists of the appropriate CODEC used by the VOIP calling software but Wireshark uses its default set to analyse the stream without us specifying the CODEC. The RTP protocol is built on the UDP protocol.
3) In the following video, I have explained how to use Wireshark to capture the Audio Stream.
VOIP LAN calling software: http://www.ssuitesoft.com/voippcphonelanchat.htm
As you can see, a CODEC samples audio coming into your audio device and using an algorithm converts into a digital output which can be used up in making audio files(.mp3, .m4a), understandable by the computer.
The same mechanism is followed vice versa while displaying some sound through your headphones or speakers.
2) So, VOIP consists of an RTP protocol which is responsible for carrying the audio stream. The RTP header consists of the appropriate CODEC used by the VOIP calling software but Wireshark uses its default set to analyse the stream without us specifying the CODEC. The RTP protocol is built on the UDP protocol.
3) In the following video, I have explained how to use Wireshark to capture the Audio Stream.
VOIP LAN calling software: http://www.ssuitesoft.com/voippcphonelanchat.htm
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