Adding 4G to architecture diagram.

Author: djrmetaswitch

articles/private-5g-core/media/azure-private-5g-core/packet-core-architecture.png

@@ -48,7 +48,7 @@ Azure Private 5G Core allows you to use Azure to easily carry out the following
 The following diagram shows the network functions supported by a packet core instance. It also shows the interfaces these network functions use to interoperate with third-party components.
 
 :::image type="complex" source="media/azure-private-5g-core/packet-core-architecture.png" alt-text="Packet core architecture diagram displaying each of the supported network functions and their interfaces.":::
-   Diagram displaying the packet core architecture. The packet core includes the following network functions: the A M F, the S M F, the U P F, the U D R, the N R F, the P C F, the U D M, and the A U S F. The A M F communicates with 5G user equipment over the N1 interface. A G Node B provided by a Microsoft partner communicates with the A M F over the N2 interface and the U P F over the N3 interface. The U P F communicates with the data network over the N6 interface. Several network functions use the N A F interface to communicate with the Application Function, which is provided by a service provider or enterprise.
+   Diagram displaying the packet core architecture. The packet core includes the following 5G network functions: the A M F, the S M F, the U P F, the U D R, the N R F, the P C F, the U D M, and the A U S F. The A M F communicates with 5G user equipment over the N1 interface. A G Node B provided by a Microsoft partner communicates with the A M F over the N2 interface and the U P F over the N3 interface. The U P F communicates with the data network over the N6 interface. Several network functions use the N A F interface to communicate with the Application Function, which is provided by a service provider or enterprise. When operating in 4G mode, the packet core includes S 11 I W F and M M E network functions. The S 11 I W F communicates with the M M E over the S 11 interface. An E Node B provided by a Microsoft partner communicates with the M M E over the S 1 M M E interface and the U P F over the S 1 U interface. 
 :::image-end:::
 
 ## Why use Azure Private 5G Core?