xApp
A microservice on the near-RT RIC implementing RAN optimization logic such as traffic steering, load balancing, or QoE optimization.
An xApp is a self-contained application that plugs into the near-RT RIC to do one optimisation job well — steer traffic, balance load across cells, protect a slice's QoE, manage interference. The point of packaging it this way is openness: in classic RAN this logic was locked inside a vendor's black-box scheduler, but as an xApp it can come from a third party or even be written in-house, as long as it speaks the RIC's interfaces.
Under the hood an xApp subscribes to RAN telemetry over E2, reasons about it (often with an ML model trained by an rApp upstream), and pushes control actions or policies back down — all inside the near-RT loop. The hard, unglamorous problem in the real world is conflict: two xApps each chasing their own goal can fight over the same parameter, one nudging a handover threshold up while another nudges it down. That's why the RIC needs conflict-mitigation logic, and why deploying many xApps together is trickier than running any single one in isolation.
Frequently asked questions
- What is the difference between an xApp and an rApp?
- Where they run and how fast. An xApp runs on the near-RT RIC and acts on a ~10 ms-to-1 s timescale over the E2 interface — real-time things like traffic steering and load balancing. An rApp runs on the non-RT RIC (in the SMO) and works on slower, network-wide tasks like ML model training, policy, and analytics over A1/O1. Loosely: rApps think and train, xApps act in near-real-time.
Related terms
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