Aviz Service Node details IMSI-based session correlation during 4G to 5G handovers

Aviz Service Node is described as a passive observability layer that correlates subscriber control-plane and user-plane sessions across hybrid 4G EPC and 5G core during inter-RAT handovers. For enterprise IT and security leaders, it targets loss of monitoring context when session identifiers change between LTE and 5G.

Research Overview

The blog frames hybrid 4G and 5G deployments as raising operational difficulty in maintaining consistent control-plane visibility as subscribers move between radio access technologies. It says traditional monitoring can lose session context during these transitions, creating troubleshooting and analytics gaps.

It positions Aviz Service Node as providing continuous, correlated subscriber session tracking across EPC and 5GC interfaces. The update claims the approach does not require changes to network configuration or mobility procedures.

Key Findings

The post states that subscriber identifier changes during inter-RAT mobility can cause monitoring tools to treat the activity as new sessions rather than a continuation. It highlights identifiers such as TEIDs, UE IPs, and QoS parameters as examples of values that can change.

It also describes handover triggers as not always explicitly exposed in signaling, so requests that appear to be new sessions may correspond to an ongoing subscriber session. The blog says Aviz Service Node validates incoming requests against existing EPC and 5GC contexts and internally treats them as handovers when appropriate.

Technical Breakdown

Aviz Service Node is described as detecting inter-RAT handovers using IMSI-based session matching and applying in-place session upgrade logic. The stated goal is to maintain a unified subscriber view during the transition between LTE and 5G.

For interface coverage, the blog attributes control-plane monitoring to S11 for EPC and N11 for 5GC, and user-plane monitoring to S1-U, N3, and N4. It says mirrored signaling and user plane traffic are ingested passively from these interfaces.

Operational Impact

The blog describes a real-time metadata export path to Kafka, with updates made during each handover transition. It says the exports are normalized and enriched so downstream analytics and monitoring tools receive synchronized session data across both EPC and 5GC domains.

It lists continuity of KPIs such as latency, packet loss, and handover success rate as outcomes tied to linked control-plane and user-plane contexts. It also states the service node does not sit in the live traffic path and therefore is not intended to affect live packet flow.

Overall, the blog presents Aviz Service Node as a passive mechanism for correlating and upgrading subscriber sessions during inter-RAT handovers between 4G EPC and 5G core, with real-time metadata streaming to Kafka. Blog Signals brief is a fact-based summary of the vendor blog.