How to connect two eNBs to one MME

Let's say MME and ENB1 are running in a PC with IP 192.168.30.1 and ENB2 is running on a PC with IP 192.168.30.2, the configuration shall be done as following:

1. MME:
   gtp_addr: "192.168.30.1"
2. ENB2:
   mme_addr: "192.168.30.1" gtp_addr: "192.168.30.2"
3. ENB1:
   If we put "192.168.30.1", it will not work as MME is already using this address for its S1AP socket (3GPP does not allow to use a custom port). The solution is to create an IP alias:
   ifconfig eth2:1 192.168.30.3/24 up Then use this alias as gtp_addr for ENB1:
   mme_addr: "192.168.30.1" gtp_addr: "192.168.30.3"
4. Change enb_id on ENB2 to avoid both ENB having the same IDs.

Note : Radio frame must be synchronized between ENB1 and ENB2. The most convenient way is to use GPS antenna on both eNB