17.4. PDP context types
From the viewpoint of the IMS, it is important to distinguish between the PDP context types shown in Figure 17.1. A primary PDP context is used whenever the first connection with a specific APN is established. If further connections with the same APN are needed, secondary PDP contexts are established.
IMS signalling can be transported either in a dedicated signalling PDP context or a general purpose PDP context. If a dedicated signalling PDP context is established, all IMS-related media streams must be put into one or more separate secondary PDP contexts.
Over a general IMS PDP context the UE may send signalling and media streams together. Nevertheless, it still has the option to create separate PDP contexts for media in this case as well.
Get The IMS: IP Multimedia Concepts And Services, Second Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
