This section is an introduction to SIP transactions and dialogs and is suitable for those who either are working with SIP at a basic level, perhaps debugging SIP scenarios, or people that just want to know a little more. If you wish to become a SIP expert, knowing transactions and dialogs is a must. Even if your life goal isn't to become an expert in SIP, knowing what transactions and dialogs are will be tremendously helpful as soon as you do anything related to SIP, such as developing your first little application using something like JSR289 or similar. This presentation will go over: - What is a transaction. - When does a transaction begin and when does it end. - What is the relation between a dialog and a transaction. - When is a dialog established. - Why do we need dialogs?