Voice over IP Fundamentals

In the last year I have thought this course twice to companies who were starting a new VoIP project. It is an interesting training for those who have little knowledge of telephony and voice over IP networks. 

When I started with open source PBXs in 2004, one of the things I’ve noticed is, most people working with open source telephony do not have a background on VoIP protocols.

I believe this training will never be ready, there will always new devices and new technologies to cover. So I plan to update it regularly. As you have lifetime access, you will always receive the updates.

** This training is purely theoretical, no practical exercises will be applied **

VoIP Fundamentals

Here we will present the basics of VoIP

How voice is encoded digitally. In this chapter we are going to see the basics on how the voice is encoded according to the theorem of Nyquist.

• VoIP and the OSI model

• The Nyquist theorem

• Coders and Decoders

• Selecting a Codec

How the voice is packetized, synchronized and controlled using the Real Time Protocol

• Payload identification

• Sequencing

• Timestamping

• Real Time Transport Control Protocol

• RTP header compression

How the sessions are described and negotiated using the Session Description Protocol

• Offer/Answer Model

• SDP Parameters

• Main Parameters

Quiz number 1 – Voice Fundamentals

What are the most common Session Protocols and where they are in use

• Comparing and contrasting Session Protocols SIP, H323,MGCP, Skinny/SCCP,IAX

• Session Initiation Protocol, the de facto standard

• H323, the protocol from ITU

• Media Gateway Control Protocol

• Megaco

• Skinny

SIP

• Introduction to SIP

• SIP Components

• SIP Ladder and Trapezoid

• SIP requests and replies

H323

• H.323 components

• H.323 Protocols

• H.323 Protocol Suite

• H.323 Messages

• H.323 Gatekeepers

Media Gateway Control Protocol

• MGCP Intro

• MGCP Architecture

• Call Setup

Quiz number 2 – Session Protocols