MBR stands for Maximum Bit Rate, and it defines the maximum rate traffic can flow between a UE and the network.

It can be defined on several levels:

MBR per Bearer

This is the maximum bit rate per bearer, this rate can be exceeded but if it is exceeded it’s QoS (QCI) values for the traffic peaking higher than the MBR is back to best-effort.

AMBR

Aggregate Maximum Bit Rate – Maximum bit rate of all Service Data Flows / Bearers to and from the network from a single UE.

APN-MBR

The APN-MBR allows the operator to set a maximum bit rate per APN, for example an operator may choose to limit the MBR for subscriber on an APN for a MVNO to give it’s direct customers a higher speed.

(This is only applied to Non-GBR bearers)