B.1 Protocol state model for transparent mode

25.4153GPPRelease 17TSUTRAN Iu interface user plane protocols

Figure B.1 illustrates the state model for transparent mode Iu UP instances. A transparent mode instance can be in one of following states.

Figure B.1: Protocol state model for transparent mode

B.1.1 Null State

In the null state the Iu UP instance does not exist and therefore it is not possible to transfer any data through it.

Upon reception of a Iu-UP-CONFIG-Req from higher layer the Iu UP instance is created and transparent mode data transfer ready state is entered. The mode information is received either through RANAP signalling or directly in the CN node. In the Iu-UP-CONFIG-Req e.g. the following information will be indicated:

– Transparent mode.

B.1.2 Transparent Mode Data Transfer Ready State

In the transparent mode data transfer ready state, transparent mode data can be exchanged between the entities.

Upon reception of Iu-UP-CONFIG-Req indicating release from higher layer, the Iu UP instance is terminated and the null state is entered.