What Are the Interfaces Between MME and Serving GW?
I’ll explain you how the MME (Mobility Management Entity) and the Serving Gateway (SGW) communicate in an LTE network. These two components are part of the core network called EPC (Evolved Packet Core), and they work together to manage user mobility and data transfer.
The main interface that connects the MME and the Serving GW is known as the S11 interface. Let me break it down for you.
S11 Interface: The Core Link
- Function: The S11 interface is used for signaling between the MME and the SGW. It helps with creating, modifying, and releasing bearers — which are like data paths used for your internet or voice services.
- Protocol: This interface uses the GTP-C (GPRS Tunneling Protocol-Control plane) to carry signaling messages. It doesn’t carry user data — it only manages how the data should flow.
- Session Management: Whenever your device attaches to the network or moves between cells, S11 helps coordinate the session and ensure your connectivity is maintained.
So, every time you power on your LTE device or move between coverage areas, the MME and Serving GW are exchanging messages over the S11 interface to make sure everything stays connected and your data sessions remain uninterrupted.