The QoS Class Identifier (QCI) is a scalar that is used as a reference to access node-specific parameters that control bearer level packet forwarding treatment (e.g. scheduling weights, admission thresholds, queue management thresholds, link layer protocol configuration, etc.).
The Allocation and Retention Priority (ARP) primarily allows one to decide whether a bearer establishment request can be accepted or rejected in case of resource limitations.
- In addition, the ARP can be used by the eNodeB to decide which bearer(s) to drop during exceptional resource limitations (e.g. at handover).
Each GBR bearer is additionally associated with the following bearer level QoS parameter:
- GBR = Guaranteed Bit Rate, the bit rate that can be expected to be provided by a GBR bearer
- MBR = Maximum Bit rate
Each non-GBR is additionally associated with the following bearer level QoS parameter:
- UE-AMBR = UE Aggregate Maximum Bit Rate (in UL)
- APN-AMBR = APN Aggregate Maximum Bit Rate (in DL)