Section: Annex E (normative): Mapping between EPS and Release 99 QoS parameters
Content: This annex specifies how the QoS parameter values of an EPS bearer are mapped to/from the Release 99 QoS parameter values of a PDP context in PDN GW, S4-SGSN and MME. Within this specification, different names are used for the QoS parameters of a PDP context e.g. "R99 QoS profile" and "R99 QoS parameters", but nevertheless the whole QoS IE as described in TS 24.008[ Mobile radio interface Layer 3 specification; Core network protocols; Stage 3 ]  [47] is referred to including the R99 and R97/98 QoS attributes. This means that the MME performs QoS mapping, populates and forwards both R99 and R97/98 QoS attributes towards the UE in S1 mode, if the UE supports A/Gb mode or Iu mode or both. The MME also performs QoS mapping, populates and forwards both R99 and R97/98 QoS attributes also on Gn when deployed in the interoperation scenarios as listed in Annex D, clause D.2. The S4-SGSN performs QoS mapping, populates and forwards either both R99 and R97/98 QoS attributes or only R97/98 QoS attributes towards the UE in Iu mode and A/Gb mode. The P-GW performs QoS mapping, populates and forwards both R99 and R97/98 QoS attributes over Gn/Gp when deployed in the interoperation scenarios as listed in Annex D, clause D.2. The following mapping rules hold: - There is a one-to-one mapping between an EPS bearer and a PDP context. - When EPS bearer QoS parameters are mapped to Release 99 QoS parameters the pre-emption capability and the pre-emption vulnerability information of the EPS bearer ARP are ignored and the priority of the EPS bearer parameter ARP is mapped to the Release 99 bearer parameter ARP, as described in table E.1. Table E.1: Mapping of EPS bearer ARP to Release 99 bearer parameter ARP When Release 99 QoS parameters are mapped to EPS bearer QoS parameters the pre-emption capability and the pre-emption vulnerability information of the EPS bearer ARP are set based on operator policy in the entity that performs the mapping. The Release 99 bearer parameter ARP is mapped to the priority level information of the EPS bearer parameter ARP as described in table E.2. Table E.2: Mapping of Release 99 bearer parameter ARP to EPS bearer ARP The values of H (high priority) and M (medium priority) can be set according to operator requirements to ensure proper treatment of users with higher priority level information. The minimum value of H is 1. The minimum value of M is H+1. From Release 9 onwards, the priority of the EPS bearer parameter ARP is mapped one-to-one to/from the Evolved ARP parameter of a PDP context, if the network supports this parameter. NOTE 1: The setting of the values for H and M may be based on the SGSN mapping from the Release 99 bearer parameter ARP to the ARP parameter that is used for UTRAN/GERAN. NOTE 2: After a handover from UTRAN/GERAN to E-UTRAN the ARP parameter of the EPS bearer can be modified by the P-GW to re-assign the appropriate priority level, pre-emption capability and pre-emption vulnerability setting. NOTE 3: A mapping from the EPS bearer parameter ARP to the Release 99 bearer parameter ARP is not required for a P-GW when connected to an SGSN via Gn/Gp as any change of the bearer ARP parameter may get overwritten by the SGSN due to subscription enforcement. However, the P-GW should not combine services with different EPS bearer ARP values onto the same PDP context to enable a modification of the bearer ARP without impacting the assignment of services to bearers after a handover to E-UTRAN. - The EPS bearer parameters GBR and MBR of a GBR EPS bearer are mapped one-to-one to/from the Release 99 bearer parameters GBR and MBR of a PDP context associated with Traffic class 'conversational' or 'streaming'. - When EPS bearer QoS parameters are mapped to Release 99 QoS parameters the Release 99 bearer parameter MBR of PDP contexts associated with Traffic Class 'interactive' or 'background' is set equal to the value of the authorized APN-AMBR. If the APN-AMBR is modified while the UE accesses the EPS through E-UTRAN, the UE shall also set the Release 99 bearer parameter MBR to the new APN-AMBR value for all non-GBR PDP contexts of this PDN connection. The P-GW shall enforce the APN-AMBR across all PDP contexts with Traffic Class 'interactive' and 'background' for that APN. The MME or S4-SGSN may attempt to transfer APN-AMBR and UE-AMBR to a Gn/Gp SGSN - When Release 99 QoS parameters are mapped to EPS bearer QoS parameters the AMBR for the corresponding APN shall be set equal to the MBR value of the subscribed QoS profile. At handover from a Gn/Gp SGSN the MME or S4-SGSN shall provide this APN-AMBR value, if not explicitly received from the Gn/Gp SGSN, to the Serving GW and the PDN GW for each PDN connection. It is required that the subscribed MBR in the HLR/HSS is set to the desired APN-AMBR value for all subscribed APNs which may lead to a selection of a P-GW. The UE derives the APN-AMBR from the value of the MBR of a PDP context created by the PDP Context Activation Procedure as described in TS 23.060[ General Packet Radio Service (GPRS); Service description; Stage 2 ]  [7]. NOTE 5: If the pre-Rel-8 UE with the updated subscribed MBR is connected to a GGSN, the GGSN can downgrade the MBR of the PDP contexts based on either local policy or PCC (where the MBR per QCI information is provided to the PCEF). NOTE 6: From Release 9 onwards, the APN-AMBR is available on Gn/Gp. - For handover from a Gn/Gp SGSN and if the MME does not receive AMBR values from the Gn/Gp SGSN, the MME provides a local UE-AMBR to the eNodeB until MME gets the EPS subscribed UE-AMBR. When the MME gets the subscribed UE-AMBR value from the HSS, it calculates the UE-AMBR (UE-AMBR=MIN (subscribed UE-AMBR, sum APN-AMBR of all active APNs)). Then it compares this value with the local UE-AMBR and if the local UE-AMBR is different from the corresponding derived UE-AMBR, the MME initiates HSS Initiated Subscribed QoS Modification procedure to notify the derived UE-AMBR to the eNodeB. NOTE 7: The local UE-AMBR may be for example based on the summing up of the APN-AMBR values of all active APNs of the UE or on internal configuration. - A standardized value of the EPS bearer parameter QCI is mapped one-to-one to/from values of the Release 99 parameters Traffic Class, Traffic Handling Priority, Signalling Indication, and Source Statistics Descriptor as shown in Table E.3. NOTE 8: When mapping to QCI=2 or QCI=3, the Release 99 parameter Transfer Delay is used in addition to the four Release 99 parameters mentioned above. - When EPS bearer QoS parameters are mapped to Release 99 QoS parameters the setting of the values of the Release 99 parameters Transfer Delay and SDU Error Ratio is derived from the corresponding QCI's Packet Delay Budget and Packet Loss Rate, respectively. When Packet Loss Rate parameter is further mapped to Release 99 QoS parameter Reliability Class (TS 23.107[ Quality of Service (QoS) concept and architecture ]  [59], table 7), the Residual BER is considered <= 2*10-4. Also when Release 99 QoS parameters are mapped to EPS bearer QoS parameters the values of the Release 99 parameter SDU Error Ratio are ignored. - The setting of the values of all other Release 99 QoS is based on operator policy pre-configured in the MME and S4-SGSN. - In networks that support mobility from E-UTRAN to UTRAN/GERAN, if the UE has indicated support of UTRAN or GERAN, the EPS network shall provide the UE with the Release 99 QoS parameters in addition to the EPS bearer QoS parameters within EPS bearer signalling. Table E.3: Mapping between standardized QCIs and Release 99 QoS parameter values