Section: 6.5.1.4C Handling the maximum number of active user plane radio bearers in NB-S1 mode
Content: When the maximum number of active user plane radio bearers in NB-S1 mode is reached (see clause 6.5.0) and upper layers request for more DRBs for PDN connections other than PDN connections with those DRBs, the UE can choose to release one or more of the PDN connections to cater for the upper layer request. The choice of which PDN connection to be released is implementation specific. If the maximum number of active user plane radio bearers in NB-S1 mode is reached and the upper layers of the UE request user-plane resources for exception data reporting, the UE shall release a PDN connection that has user-plane resources to cater for the request for exception data reporting. The choice of which PDN connection to be released is implementation specific. If the UE needs to release a PDN connection for the reasons stated in this clause, a PDN connection that is used for exception data reporting shall not be released. If the UE releases a PDN connection to cater for the upper layer request, the UE shall release the PDN connection via explicit ESM signalling.