Subscriber correlation is the process of identifying and tracking network traffic from a specific subscriber or user across different network segments or nodes. In a packet-based network, subscriber correlation is used to associate packets with a specific subscriber or user, enabling network operators to gain insight into individual subscriber behaviour, monitor service quality, and troubleshoot network issues.

Subscriber correlation is typically achieved by assigning a unique identifier to each subscriber, such as an IMSI, IMEI, MS-ISDN. As packets traverse the network, the identifier is used to associate each packet with the corresponding subscriber, allowing network operators to track traffic flows, monitor usage patterns, and analyse service quality.

Subscriber correlation is particularly important in mobile networks, where subscribers can move between different network segments or nodes as they roam between different geographic areas. By correlating traffic from a specific subscriber across different network elements, network operators can gain a holistic view of subscriber behaviour, detect and diagnose network issues, and optimize network performance and capacity.

How IMSI IMEI MSISDN is related to GTP mobile correlation on packet brokers:

In mobile networks, the International Mobile Subscriber Identity (IMSI), International Mobile Equipment Identity (IMEI), and Mobile Station International Subscriber Directory Number (MSISDN) are unique identifiers used to identify and authenticate mobile subscribers.

Packet brokers can use these identifiers to perform subscriber correlation in GPRS Tunneling Protocol (GTP) traffic. For example, when a mobile device connects to a network, it sends a GTP-C Create Session Request message to the core network. This message includes information such as the IMSI, IMEI, and MSISDN, as well as other session-related information.

The packet broker can use the IMSI, IMEI, and MSISDN to correlate GTP-U user data packets with the corresponding subscriber session established using GTP-C messages. This enables the packet broker to track user data flows across different network elements and nodes, allowing network operators to gain visibility into subscriber behaviour and troubleshoot network issues.

For example, if a subscriber is experiencing poor service quality, the packet broker can identify the IMSI, IMEI, and MSISDN associated with the subscriber and track their user data flows across different network elements. This can help the network operator pinpoint the root cause of the issue and take appropriate actions to address it.

In summary, IMSI, IMEI, and MSISDN are unique identifiers used to identify and authenticate mobile subscribers, and they are used by packet brokers to perform subscriber correlation in GTP mobile traffic.