The GUTI, or Globally Unique Temporary Identity, is a crucial concept in 5G (fifth generation) mobile networks, serving as an essential identifier for User Equipment (UE) within the network. The GUTI is designed to provide a temporary and globally unique identity for a UE, ensuring privacy and security during communication with the 5G network. Here’s a detailed explanation of the GUTI in the context of 5G:
- Purpose of GUTI:
- Privacy: One of the primary purposes of the GUTI is to enhance user privacy. Instead of using a permanent and globally unique identifier, like the International Mobile Subscriber Identity (IMSI), the GUTI is temporary and changes frequently. This limits the exposure of a user’s long-term identity and reduces the risk of tracking and profiling.
- Security: The use of temporary identities like GUTI adds a layer of security to the communication between the UE and the network. Constantly changing identifiers make it more challenging for malicious entities to intercept and exploit user information.
- Composition of GUTI:
- The GUTI is composed of two main parts:
- GUMMEI (Globally Unique MME Identity): This part identifies the MME (Mobility Management Entity) that currently serves the UE. It includes the PLMN ID (Public Land Mobile Network Identity) and the MME Group ID.
- M-TMSI (Mapped Temporary Mobile Subscriber Identity): This part uniquely identifies the UE within the serving MME. It is temporary and can change during certain events, such as handovers.
- The GUTI is composed of two main parts:
- GUTI Allocation and Update:
- The GUTI is allocated by the MME during the initial attach procedure when the UE connects to the 5G network. It is then used for subsequent communication between the UE and the network.
- The GUTI can be updated during certain events, such as:
- Location Update: When the UE moves to a new tracking area or location area, the GUTI may be updated to reflect the new serving MME and M-TMSI.
- Handover: During a handover between cells or MMEs, the GUTI may be updated to maintain continuity in communication.
- Temporary Nature and Timer Mechanism:
- The GUTI is temporary and is intended to change periodically to enhance security and privacy.
- A timer mechanism is involved in GUTI management. If the UE remains inactive for an extended period, the GUTI may be marked as invalid, and a new GUTI will be allocated during the next communication with the network.
- Role in Handovers:
- During handovers, the GUTI is essential for maintaining continuity in communication. It allows the network to uniquely identify and track the UE even as it moves across different cells or MMEs.
- Support for Network Slicing:
- In the context of network slicing in 5G, the GUTI plays a role in supporting the isolation and customization of services within specific slices. It contributes to the unique identification of UEs within the context of a particular network slice.
In summary, the GUTI in 5G serves as a temporary and globally unique identifier for User Equipment, contributing to enhanced privacy, security, and efficient communication within the network. It plays a crucial role in identifying and tracking UEs while minimizing the exposure of long-term user identities.