What is APN and PDN and What is the Difference between them?

Question

Which one of the below understanding is correct:

APN-AMBR defines the total bit rate that is allowed for all non-GBR bearers for all UEs associated with a specific APN,
or
Is this the total bit rate that is allowed for all non-GBR bearers for a single UE associated with a specific APN,

Also could someone please share typical setting for APN-AMBR and UE-AMBR from real network.

Answer 1

What is PDN?
PDN is a network established for the specific purpose of providing data transmission services.
What is APN?
APN is nothing but link between two networks(i.e simple case, LTE and external world).
Difference between them.
APN is one who identifies a PDN-GW. How?
APN structure is comprised into two parts: 1) Network identifier and 2) operator identifier.
- Network identifier which defines the PDN to which the UE requests connectivity, and Operator identifier which defines in which Public Land Mobile Network (PLMN) the PDN-GW is located.