LTE: how eNodeB selects a MME (FIRST attach)?

Question

I'm trying to figure out how eNodeB can select the MME, as far as I know, I think eNodeB query to a DNS (iDNS?) with the TAI FQDN, is made up with TAC low bit, TAC high bit, MCC and MNC I mean something like

tac-lb.tac-hb.tac.epc.mnc.mcc.3gppnetwork.org

but where eNodeB send that TAI FQDN?? Is there a list into eNodeB with the MMEI?

Where is the DNS? How eNodeB query it?

In case of eNodeB already has a MMEI list into it.... Any example? Any eNodeB config file? Something that can help me to reach out to understand?

Regards

Answer 1

The concept is based on MME selection function in section 4.3.8.3 of 23.401 3GPP specification. 'The MME selection function selects an available MME for serving a UE. The selection is based on network topology, i.e. the selected MME serves the UE's location and for overlapping MME service areas, the selection may prefer MMEs with service areas that reduce the probability of changing the MME. When a MME/SGSN selects a target MME, the selection function performs a simple load balancing between the possible target MMEs.'