Section: 4.3.18.3 Priority EPS Bearer Services
Content: The Service User receives on demand priority treatment according to its MPS profile, i.e. On-Demand. If the Service User is not authorized to use on-demand priority request, the Service User receives priority treatment (i.e. appropriate ARP and QCI ) at initial attach for all bearers, based on user profile data stored in the HSS/SPR and authorized by the PCRF (see TS 23.203[ Policy and charging control architecture ]  [6], clause 7.2). An On-Demand Service User requires explicit invocation/revocation via SPR MPS user profile update (see TS 23.203[ Policy and charging control architecture ]  [6], clause 7.5). Since MPS user profile are part of inputs for PCC rules, the update will trigger PCC rules modification to achieve appropriate ARP and QCI settings for bearers (see TS 23.203[ Policy and charging control architecture ]  [6], clause 7.4.2). When the eNodeB receives mobile initiated signalling with establishment cause set to highPriorityAccess, the eNodeB handles the RRC connection request with priority. When the MME receives and verifies mobile initiated signalling with establishment cause set to highPriorityAccess, the MME establishes the S1 bearer with priority. Based on MPS EPS priority subscription, MME can verify whether the UE is permitted to handle the request preferentially comparing to other UEs not prioritized. An AF for MPS Priority Service is used to provide Priority EPS Bearer Services using network-initiated resource allocation procedures (via interaction with PCC) for originating accesses. NOTE: Use of 3rd party AF for MPS services for Service Users is outside the scope of 3GPP specification.