Section: 5.4.4.2 MME Initiated Dedicated Bearer Deactivation
Content: MME initiated Dedicated Bearer Deactivation is depicted in Figure 5.4.4.2-1 below. This procedure deactivates dedicated bearers. Default bearers are not affected. To initiate the release of the full PDN connection including the default bearer, the MME uses the UE or MME requested PDN disconnection procedure defined in clause 5.10.3. Figure 5.4.4.2-1: MME initiated Dedicated Bearer Deactivation NOTE 1: For a PMIP-based S5/S8, procedure steps (A) and steps (B) are defined in TS 23.402[ Architecture enhancements for non-3GPP accesses ]  [2]. Steps 3, 4, 5 and 9 concern GTP based S5/S8 0. Radio bearers for the UE in the ECM-CONNECTED state may be released due to local reasons (e.g. abnormal resource limitation or radio conditions do not allow the eNodeB to maintain all the allocated GBR bearers: it is not expected that non-GBR bearers are released by the eNodeB unless caused by error situations). The UE deletes the bearer contexts related to the released radio bearers. 1. When the eNodeB releases radio bearers in step 0, it sends an indication of bearer release to the MME. This indication may be e.g. the Bearer Release Request (EPS Bearer Identity) message to the MME, or alternatively Initial Context Setup Complete, Handover Request Ack and UE Context Response, Path Switch Request may also indicate the release of a bearer. The eNodeB includes the ECGI and TAI in the indication sent to the MME. The eNodeB also includes the PSCell ID if Dual Connectivity is active for the UE in the RAN. If the PLMN has configured secondary RAT reporting and the eNodeB has Secondary RAT usage data to report, the Secondary RAT usage data is included. 2. The MME sends the Delete Bearer Command (EPS Bearer Identity, User Location Information, UE Time Zone, RAN/NAS Release Cause if available, Secondary RAT usage data, PSCell ID) message per PDN connection to the Serving GW to deactivate the selected dedicated bearer. RAN/NAS Release Cause indicates the RAN release cause and/or the NAS release cause. RAN/NAS Release Cause is only sent by the MME to the PDN GW if this is permitted according to MME operator's policy. If the MME received Secondary RAT usage data in step 1, the MME shall include it in this message. If MME received PSCell ID in step 1, the MME shall include it in this message. 3. The Serving GW sends the Delete Bearer Command (EPS Bearer Identity, User Location Information, UE Time Zone, RAN/NAS Release Cause, Secondary RAT usage data) message per PDN connection to the PDN GW. The Serving GW includes the Secondary RAT usage data it in this message if it was received in the previous message and if PGW secondary RAT usage data reporting is active. 4. If PCC infrastructure is deployed, the PDN GW informs the PCRF about the loss of resources by means of a PCEF-initiated IP-CAN Session Modification procedure as defined in TS 23.203[ Policy and charging control architecture ]  [6] and provides the User Location Information, UE Time Zone and RAN/NAS Release cause (if available) received in the Delete Bearer Command from the S-GW if requested by the PCRF as defined in TS 23.203[ Policy and charging control architecture ]  [6]. The PCRF sends an updated PCC decision to the PDN GW. NOTE 2: User Location Information and UE Time Zone might not be available if the MME or the Serving GW are of a previous release and did not provide this information. 5. The PDN GW sends a Delete Bearer Request (EPS Bearer Identity) message to the Serving GW. 6. The Serving GW sends the Delete Bearer Request (EPS Bearer Identity) message to the MME. 7. Steps between steps 4 and 7, as described in clause 5.4.4.1, are invoked. This is omitted if the bearer deactivation was triggered by the eNodeB in step 0 and step 1. This is also omitted if the MME initiated bearer release due to failed bearer set up during handover, the UE and the MME deactivate the failed contexts locally without peer-to peer ESM signalling. 8. The MME deletes the bearer contexts related to the deactivated EPS bearer and acknowledges the bearer deactivation to the Serving GW by sending a Delete Bearer Response (EPS Bearer Identity, User Location Information (ECGI), Secondary RAT usage data) message. The MME includes the Secondary RAT usage data if it received this in step 7 from the eNodeB. 9. The Serving GW deletes the bearer context related to the deactivated EPS bearer and acknowledges the bearer deactivation to the PDN GW by sending a Delete Bearer Response (EPS Bearer Identity, Secondary RAT usage data) message. The Serving GW includes the Secondary RAT usage data if it was received in step 8 and if PGW secondary RAT usage data reporting is active.