# Message Type

The Message Type column provides information on the exact messages exchanged between AMF, MME, ENB, GNB & HSS

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| Message-Type      | Description                                                                                                                                                                                                                                             | Core-Type |
| ----------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | --------- |
| S1 Setup Request  | eNodeB initiates the procedure by sending S1 (Radio Trunk) Setup Request message including the appropriate data to the MME. This message contains TAC ,eNodeB name ,eNodeB IP and its PLMN. This message is sent by eNodeB to MME                       | 4G        |
| NG Setup Request  | gNodeB initiates the procedure by sending NG (Radio Trunk) Setup Request message including the appropriate data to the AMF. This message contains TAC ,gNodeB name ,gNodeB IP and its PLMN. This message is sent by gNodeB to AMF                       | 5G        |
| S1 Setup Response | MME responds with S1 (Radio Trunk) Setup Response message including the appropriate data. When this procedure is finished, the S1 (Radio Trunk) interface is operational and other S1 messages can be exchanged. This message is send by MME to eNodeB. | 4G        |
| NG Setup Response | AMF responds with NG (Radio Trunk) Setup Response message including the appropriate data. When this procedure is finished, the N2 (Radio Trunk) interface is operational and other N2 messages can be exchanged. This message is send by AMF to gNodeB. | 5G        |
| S1 Setup Failure  | This indicates the failure of the S1 setup (Radio Trunk) with MME. This message is sent by the MME to eNodeB to indicate the S1 (Radio Trunk) Setup failure.                                                                                            | 4G        |
| NG Setup Failure  | This indicates the failure of the NG setup (Radio Trunk) with AMF. This message is sent by the AMF to gNodeB to indicate the NG (Radio Trunk) Setup failure.                                                                                            | 5G        |
| S1 Disconnect     | This message indicates that the SCTP connection between the 4G radio and MME is disconnected. One reason could be Radio is rebooted.                                                                                                                    | 4G        |
| gNB Disconnect    | This message indicates that the SCTP connection between the 5G radio and AMF is disconnected. One reason could be Radio is rebooted.                                                                                                                    | 5G        |
| HSS Connect       | S6a connection between the edge to HSS host is up. We support two HSS host Cloud and Local. "hss-type" parameter indicates primary or secondary HSS.                                                                                                    | 4G        |
| HSS Disconnect    | S6a connection between the edge to HSS host is down. We support two HSS host Cloud and Local. "hss-type" parameter indicates primary or secondary HSS.                                                                                                  | 4G        |