The Foundations of SIP
4.1 (122 ratings)
Instead of using a simple lifetime average, Udemy calculates a course's star rating by considering a number of different factors such as the number of ratings, the age of ratings, and the likelihood of fraudulent ratings.
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The Foundations of SIP

Learn the fundamentals of SIP to advance your VoIP career.
4.1 (122 ratings)
Instead of using a simple lifetime average, Udemy calculates a course's star rating by considering a number of different factors such as the number of ratings, the age of ratings, and the likelihood of fraudulent ratings.
715 students enrolled
Created by Keith Croxford
Last updated 7/2017
Current price: $40 Original price: $60 Discount: 33% off
30-Day Money-Back Guarantee
  • 4.5 hours on-demand video
  • 4 Supplemental Resources
  • Full lifetime access
  • Access on mobile and TV
  • Certificate of Completion
What Will I Learn?
  • Pass SIP related questions in a job interview
  • Troubleshoot SIP issues
  • Explain how calls flow in a SIP network
View Curriculum
  • You should have a general understanding of networking

SIP is  the standard in Voice Over IP communications.  Large telecom carriers are switching away from their legacy platforms into highly scalable next generation SIP networks. Even cellular phones are migrating to Voice Over LTE, which also relies on the SIP protocol.

By taking this course you will learn the fundamentals of the SIP protocol.  Knowledge of SIP has enabled me to land secure positions with world wide telecommunication companies. Are you ready for the same opportunities? 

In this course you will learn: 

  • What is SIP and the RFCs that it is defined in. 
  • The different types of SIP clients and servers
  • The structure of SIP messages
  • Overview of SIP response codes
  • The structure of the SIP URI
  • Overview of SIP headers and their purpose
  • How the Session Description Protocol (SDP) works
  • How SIP allows mobility through call forking, REFER requests and Diversions
  • The details of SIP transactions and Dialogs
  • How SIP proxies route requests (We discuss stateful and sateless proxies)
  • The SIP Trapezoid model
  • How SIP Registration works. 
  • How SIP Authentication works. We dive into how the MD5 hash is created. 
  • What challenges SIP faces with NAT and how to overcome them.
  • An overview of the Real Time Protocol - AKA RTP

This course is created for: 

  • IT Generalists wanting to learn a specialized skill.
  • Technical support staff working for a VOIP provider
  • Service Delivery staff that deploys VOIP networks for customers. 
  • Voice Engineers that want to increase their knowledge on SIP.
  • Central Office Engineers that need to learn SIP while they transition away from circuit switched networks. 
  • Sales Engineers that want to close more deals.

About the Instructor :  

Keith Croxford has been involved in VOIP and networking technologies for over 14 years. He has received accolades from VOIP industry experts. Here are a few examples : 

"Keith is one of those rare engineering breeds that is exceptional in knowledge and communicating that knowledge. It is a great team player and has assisted in resolving hard issues that no one else can fix. Keith is intelligent, detailed, self disciplined, works well with others, and great at documentation. When it comes to voice engineering, there has never been a better one." - CTO

"Keith is the Swiss Army of knife of VOIP and Data networking technologies with a healthy dose of great Programming skills and Customer Experience management. It is very tough to find a Jack of All Trades and a Master of a Few and Keith is one of them. I've interacted with him in deeply technical and business related circumstances and he hits the ball out of the park in both. His work ethic is second to none. He also demonstrates a very high entrepreneur mindset." - Director of Service Delivery 

Start Learning Now!

This same material is presented in live conferences that cost $400 per seat to attend. Through Udemy you are able to receive this course at an incredible value.

Click on "Take this course" and start learning now. 

Who is the target audience?
  • This course is best suited for technical support engineers that want to advance their career.
  • This course is not for someone wanting to learn about Cisco Call Manager
  • This course is not for someone wanting to learn about any specific vendor's SIP stack
Curriculum For This Course
31 Lectures
Introduction and Overview
1 Lecture 01:21

This is a quick introduction about the course. You will learn a little bit about the instructor and get an overview of what this course will cover. 

Preview 01:21
General SIP Overview
2 Lectures 23:28

In this module you will learn about SIP, the RFCs that define it and where SIP resides in the OSI model. 

Preview 07:14

What is SIP?
2 questions

SIP Clients and Server
1 Lecture 07:50
What is the difference between a SIP Client and SIP Server?
SIP Messages
14 Lectures 01:45:26
What does a SIP message look like?

What is a SIP response code?

1XX Response Codes

2xx - 3xx Response Codes

Wireshark Review - Examine a 2xx response

200 OK Capture quiz
1 question

4xx Response Codes

5xx Response Codes

6xx Response Codes

What is a SIP URI and how is it structured?

How is a SIP header structured?

What is an SDP and how does it affect media?

How does SIP allow user mobility?
SIP Authentication
1 Lecture 06:27
SIP Routing and Responses
3 Lectures 28:02
Why are SIP transactions and dialogs important?

How does SIP Route calls?

The SIP trapezoid model.
1 Lecture 11:00
How does SIP registration work?
The problem with NAT
1 Lecture 14:35
What challenges does SIP face with NAT?
Media and RTP
1 Lecture 11:11
Overview of the Real Time Protocol
Using Wireshark to Capture and Troubleshoot SIP
3 Lectures 23:59
Overview of capturing SIP traffic

Watch this to see how easy it is to install Wireshark. I install on OSX in this video. Linux and Windows are just as easy. 

Installing Wireshark

General Wireshark options and starting your first capture.
1 More Section
About the Instructor
Keith Croxford
4.2 Average rating
158 Reviews
2,851 Students
2 Courses
Director of Technology

Over the past 14 years I have been involved in information technology. 10 years of this has been focused on carrier / ISP voice and data networks.  I've built networks from the ground up. Literally.  I've worked on everything from outside plant (the wires in the ground) to the devices that deliver VOIP services to your home or business. 

A few things I've done with my career : 

Contracting with the US Army to build fiber optic infrastructure for their secure and non-secure networks. 

Deploying Metaswitch based voice services to businesses. 

Upgrading a network to be MPLS capable which allowed an ISP to add a lot of new services. 

Being part of an engineering team that lead Vonage to purchase Telesphere Networks

Creating fraud detection and analysis tools to stop VOIP hackers. 

Frequently I am asked to teach a concept to someone. This lead me to create my Udemy instructor profile. 

I strive to make these teaching sessions informative, fun, and upbeat.

See for yourself. Sign up for one of my courses today.