APN-AMBR

[3GPP 23.401] Each APN access, by a UE, is associated with per APN Aggregate Maximum Bit Rate (APN-AMBR).

The APN‑AMBR is a subscription parameter stored per APN in the HSS. It limits the aggregate bit rate that can be expected to be provided across all non‑GBR bearers and across all PDN connections of the same APN (e.g. excess traffic may get discarded by a rate shaping function). Each of those non‑GBR bearers could potentially utilize the entire APN‑AMBR, e.g. when the other non‑GBR bearers do not carry any traffic. GBR bearers are outside the scope of APN‑AMBR. The P‑GW enforces the APN‑AMBR in DL. Enforcement of APN‑AMBR in UL is done in the UE and additionally in the P‑GW.

All simultaneous active PDN connections of a UE that are associated with the same APN shall be provided by the same P-GW.

Fig. 1 APN-AMBR

APN-AMBR applies to all PDN connections of an APN. For the case of multiple PDN connections of an APN, if a change of APN-AMBR occurs due to local policy or the P‑GW is provided the updated APN-AMBR for each PDN connection from the MME or PCRF, the P‑GW initiates explicit signalling for each PDN connection to update the APN-AMBR value.

Fig. 2 APN-AMBR Setting

UE-AMBR

[3GPP 23.401] Each UE in state EMM-REGISTERED is associated with per UE Aggregate Maximum Bit Rate (UE-AMBR).

The UE‑AMBR limits the aggregate bit rate that can be expected to be provided across all non‑GBR bearers of a UE (e.g. excess traffic may get discarded by a rate shaping function). Each of those non‑GBR bearers could potentially utilize the entire UE‑AMBR, e.g. when the other non‑GBR bearers do not carry any traffic. GBR bearers are outside the scope of UE AMBR. The E‑UTRAN enforces the UE‑AMBR in UL and DL.

Fig. 3 UE-AMBR

The UE‑AMBR is limited by a subscription parameter stored in the HSS. The MME shall set the UE‑AMBR to the sum of the APN‑AMBR of all active APNs up to the value of the subscribed UE‑AMBR.

Fig. 4 UE-AMBR Setting