Section: 6.1.4 Coordination between ESM and SM
Content: For inter-system change from S1 mode to A/Gb mode or Iu mode, SM uses the following parameters from each active EPS bearer context: - EPS bearer identity to map to NSAPI; NOTE 1: If the UE and the MME support signalling for a maximum number of 15 EPS bearer contexts, any active EPS bearer contexts using EPS bearer identity 1 to 4 are not mapped but deactivated locally before inter-system change to A/Gb mode or Iu mode. - linked EPS bearer identity (if available) to map to linked TI; - PDN address and APN of the default EPS bearer context to map to PDP address and APN of the default PDP context; - TFT of the default EPS bearer context, if any, to map to the TFT of the default PDP context; - TFTs of the dedicated EPS bearer contexts to map to TFTs of the secondary PDP contexts; and - GERAN/UTRAN parameters as provided by the MME while on E-UTRAN access, i.e. R99 QoS, LLC SAPI, radio priority, packet flow identifier, transaction identifier and BCM (if available). If the MME also provided an Extended EPS QoS IE, then the bit rates signalled with this IE are also applicable to the R99 QoS. NOTE 2: Some networks not supporting mobility from S1 mode to A/Gb mode or Iu mode or both do not provide the UE with the GERAN/UTRAN parameters. However, for this case there is no need for the UE to perform mapping to GERAN/UTRAN parameters (i.e. the PDP contexts cannot be transferred to A/Gb mode or Iu mode). The MME performs the mapping from EPS to R99 QoS parameters according to 3GPP TS 23.401[ General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access ]  [10], annex E. At inter-system change from S1 mode to A/Gb mode, SM shall not activate the PDP context(s) if SM does not have the following parameters from the active EPS bearer context(s): - LLC SAPI; - radio priority; - transaction identifier; and - R99 QoS. At inter-system change from S1 mode to Iu mode, SM shall not activate the PDP context(s) if SM does not have the following parameter from the active EPS bearer context(s): - transaction identifier; and - R99 QoS. For inter-system change from A/Gb mode or Iu mode to S1 mode, ESM uses the following parameters from each active PDP context: - NSAPI to map to EPS bearer identity; - NSAPI of the default PDP context to map to linked EPS bearer identity; - PDP address and APN of the default PDP context to map to PDN address and APN of the default EPS bearer context; - TFT of the default PDP context, if any, to map to the TFT of the default EPS bearer context; and - TFTs of the secondary PDP contexts to map to the TFTs of the dedicated EPS bearer contexts. The MME and the UE perform the mapping from R99 to EPS QoS parameters according to 3GPP TS 23.401[ General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access ]  [10], annex E. In particular the MME derives the APN-AMBR for the corresponding PDN connection from the MBR of the R99 subscribed QoS profile and the UE maps the MBR of its default PDP context to the APN-AMBR of the corresponding PDN connection.