LTE: What does mean by Handling of Wild Card APN ?

Question

I have seen GTP control messages and found that F-TEID consists of an IP address and 32 bit long Tunnel Id. For example: Create Session Response message contains control plane F-TEID and user plane F-TEIDs. I have a question here, why not only TEIDs are included in Create Session Response message when IP address would be common ? or Does it mean control and user plane both F-TEIDs may have different IP address ?

Answer 1

When the wild card APN is present in the subscription context, the UE is authorized to connect to APNs which are not present in the subscription context.
When a request is received for registering a PDN GW ID and there is no PDN subscription context with this APN, the nodes (HSS/MME/ S4 SGSN) shall store the PDN GW ID - APN relation for the UE.
When a request is received for deregistering of PDN GW ID and there is no PDN subscription context with this APN, the nodes (HSS/MME/S4 SGSN) shall delete the PDN GW ID - APN relation from the list of APN - PDN GW ID relations.