Section: 7.2.25 Modify Access Bearers Response
Content: If an SGW supports the MABR feature (see clause 8.83), the SGW shall send a Modify Access Bearers Response message on the S11 interface to an MME as a response to a Modify Access Bearers Request message. If handling of all default bearers to be modified fails, then Cause at the message level shall be a failure cause. Possible Cause values are specified in Table 8.4-1. Message specific cause values are: - "Request accepted". - "Request accepted partially". - "Context not found". - "Service not supported". - "Modifications not limited to S1-U bearers" The SGW shall send the cause value "Modifications not limited to S1-U bearers" if - it can not serve the MME Request without corresponding S5/S8 signalling other than to unpause charging in the PGW, or without corresponding Gxc signalling when PMIP is used over the S5/S8 interface, or - if there are suspended non-GBR bearers for that UE in the SGW (NOTE 3). Upon receipt of that cause value, the MME shall repeat its request using Modify Bearer Request message per PDN connection. NOTE 1: This cause value is introduced for forward compatibility between an MME implementing this version of the specification and an SGW implementing a more recent version requiring the SGW to send S5/S8 signalling. NOTE 2: During an Inter-MME Intra-SGW handover/TAU, if the SGW, PGW and the old MME support the partial failure handling feature but the new MME doesn't, the SGW needs to inform the PGW about the change of FQ-CSID (see clause 16.2.5 of 3GPP TS 23.007[ Restoration procedures ]  [17]). If the SGW receives a Modify Access Bearers Request from the new MME, it can force the MME to send individual Modify Bearer Request message per PDN connection by returning the cause value "Modifications not limited to S1-U bearers". NOTE 3: There may be some suspended non-GBR bearers in the SGW during an Inter-MME Intra-SGW Tracking Area Update without SGW Change when the UE is coming back to E-UTRAN via a different MME than the MME serving the UE before the CSFB or SRVCC call. Table 7.2.25-1: Information Elements in a Modify Access Bearers Response Table 7.2.25-2: Bearer Context modified within Modify Access Bearers Response Table 7.2.25-3: Bearer Context marked for removal within Modify Access Bearers Response Table 7.2.25-4: Load Control Information within Modify Access Bearers Response Table 7.2.25-5: Overload Control Information within Modify Access Bearers Response