How it Works

The bearer modification for an EPS session on SMF works with the following modifications:

  • PCF and MME-Initiated Bearer Modifications for EPS session on SMF—These procedures are used either when one or multiple EPS Bearer QoS parameters QCI, GBR, MBR, or ARP are modified or to modify the APN-AMBR. The PCF-initiated or the MME-initiated bearer modification procedures do not support the modification from a QCI of non-GBR resource type to a GBR resource type QCI and vice versa.

  • X2 and S1 Based Handover for EPS Session Connected to SMF—The X2-based handover procedure is used to hand over a UE from a source eNodeB to a target eNodeB using X2. In this procedure, the MME is unchanged and the MME determines to relocate the SGW.

    The S1-based handover procedure is used when the X2-based handover cannot be used. The source eNodeB initiates a handover by sending the Handover Required message over the S1-MME reference point. This procedure may relocate the MME or the SGW.