23.1953GPPProvision of User Equipment Specific Behaviour Information (UESBI) to network entitiesRelease 5TS
The UESBI-Iu is specific to the RRC connection. The RNC shall use all sources of UESBI-Iu and update it with the latest received UESBI-Iu. Common ID messages that do not contain UESBI-Iu shall not cause the RNC to change or delete any UESBI-Iu that the RNC has already received.
Note: this requirement is intended to cover situations such as (a) UESBI-Iu is only received from one CN domain, (b) the UESBI-Iu received from CS and PS domains are different, (c) etc.
If UESBI-Iu is received after, instead of before, the RANAP Security Mode Command, then the RNC should use the UESBI-Iu for its future actions.
When the UESBI-Iu is not received for a UE, then the RNC shall assume that the UE has some default capability. This default capability is RNC implementation dependent.