What will happen if APN configuration is not present in the Entity, say HSS ?

Question

It's just a general question, popped up when i was reading a document. For instance Suppose an APN configuration of an message say Update Location Request (ULR) is not present in HSS and MME has sent the message which has reached there in HSS. What will be the reaction of HSS?

Answer 1

You might be reading TS 29.272 Section 5.2.1.1.3 Detailed behaviour of the HSS

If the Update Location Request is received over the S6a interface, and the subscriber has not any APN configuration,the HSS shall return a Result Code of DIAMETER ERROR UNKNOWN EPS SUBSCRIPTION.

If the Update Location Request is received over the S6d interface, and the subscriber has neither an APN configuration profile nor GPRS subscription data, the HSS shall return a Result Code of DIAMETER ERROR UNKNOWN EPS SUBSCRIPTION.

Error Code *DIAMETER ERROR UNKNOWN EPS SUBSCRIPTION (5420):*

This result code shall be sent by the HSS to indicate that no EPS subscription is associated with the IMSI.
This error is a permanent failure. Errors that fall within the Permanent Failures category shall be used to inform the peer that the request has failed and should not be attempted again. The Result-Code AVP values defined in Diameter Base Protocol RFC-3588/6733 shall be applied. When one of the result codes defined here is included in a response, it shall be inside an Experimental-Result AVP and the Result-Code AVP shall be absent.