MME is not responding to S1 setup request message

Question

What is the eNB behavior in-case MME is not responding to S1 setup request message (ie. MME is not sending S1 setup failure or success).

Answer 1

Googled and found the following -

The specifications say that if the eNB receives “S1 setup failure” message, it includes the indicated time before retaining the S1 setup towards the same MME (TS 36.413). They does not say anything what happens if there’s no message incoming from the MME, but I presume, that it is up to the vendor that shall define another timer which the eNB uses (at expiry) to resend the message to the same MME. Another option is, that the eNB at this “vendor dependent timer” expiry will try to reach another MME (if connected to more than one), by sending “S1 setup request” message.