SMF and UPF Emulation with PFCP Traffic over 5G N4 Interface
End‑to‑end PFCP simulation across the 5G N4 interface between SMF and UPF. MAPS™ 5G brings control‑plane and user‑plane verification together in one powerful, standards‑compliant solution.
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Overview
GL’s Message Automation & Protocol Simulation (MAPS™) 5G N4 Interface Emulator is a powerful solution for emulating Packet Forwarding Control Protocol (PFCP) signaling between the Session Management Function (SMF) and User Plane Function (UPF) over the N4 interface, in compliance with 3GPP standards. It accurately simulates the control and user plane separation (CUPS) architecture in 5G Core networks, supporting validation of network behavior in a controlled setup. The emulator replicates key SMF and UPF functions, including tunnel management for PDU session establishment, modification, and release. It also supports session-independent signaling procedures, where SMF manages policy rules and session lifecycle while UPF handles data forwarding and usage reporting.
In addition to protocol emulation, MAPS™ 5G N4 offers comprehensive testing capabilities such as error tracking, regression testing, conformance testing, and load generation. Users can run predefined or customized test scenarios using powerful built-in tools like the Message Editor, Script Editor, and Profile Editor for precise configuration of PFCP messages and call flows. It also supports user-plane traffic generation and reception through Mobile Traffic Core – GTP (ETH101) and Gateway (ETH102) licenses, enabling GTP-U stream and gateway-level traffic simulation for 5G and LTE networks. With strong automation, scalability, and integration support, MAPS™ 5G N4 is an ideal choice for equipment vendors, service providers, and test labs aiming to validate and accelerate 5G core network deployments.
Key Features
- PFCP Control-Plane: Emulate all SMF/UPF node procedures, including session lifecycle, heartbeat, and node associations
- User-Plane Traffic: GTP U streaming, HTTP/PCAP generation, scalable to 40 Gbps with licensed modules
- Test Automation: GUI, CLI, scripting, API control, scheduling, regression and load testing
- Custom Scenarios: Flexible editors allow message-level and call-flow customization
- Detailed Analytics: Call statistics, packet logs, traffic reports, graphs, and alerts for in-depth diagnostics
- Modular Architecture: Combine with other MAPS™ modules (N1/N2, N8, N10, etc.) for full 5G Core coverage
- High UE Load Emulation: The system can simulate tens of thousands of UEs, ideal for large-scale performance and stress tests
- Gateway Functionality: It includes gateway support to forward GTP mobile traffic to external IP networks (via ETH100/101)
Benefits
- Accelerate Time to Market – Ready to use test flows and a powerful scripting environment make it easy to validate session lifecycle and traffic handling
- Minimize Integration Risk – Isolate and test SMF or UPF DUTs while MAPS™ emulates the rest of the network in a controlled wrap around setup
- Scale and Stress with Confidence – Simulate massive UE loads and high density data flows. Generate tens of thousands of PFCP sessions and full GTP traffic—round the clock
- Full Customization and Visibility – Modify every PFCP IE via Message, Script, and Profile Editors. Access real time metrics, logs, and diagnostics for deep analysis
- Enterprise Grade Integrations – Control the emulator remotely via RESTful CLI/Python interfaces. Ideal for DevOps pipelines and multi site deployment
Why Choose MAPS™ 5G N4 Emulator?
- Comprehensive PFCP Emulation: Simulate SMF and UPF roles per 3GPP standards (TS 23.501/502, TS 29.244). Handle session establishment, modification, deletion, heartbeats, associations, and node level procedures flawlessly
- Control Plane and User Plane Integration: Beyond PFCP signaling, drive real mobile traffic via GTP U, HTTP, or PCAP streams—optionally scaling to 40 Gbps with PacketLoad™
- Robust, Automated Testing: Leverage built in scripts, CLI/Python APIs, and scheduler support for continuous regression, edge-case, performance, and conformance testing
Frequently Asked Questions (FAQs)
- What is MAPS™ 5G N4 Interface Emulator?
- The MAPS™ 5G N4 Interface Emulator is a protocol simulation tool that emulates PFCP signaling between the Session Management Function (SMF) and User Plane Function (UPF) over the N4 interface in 5G Core network. It allows users to test, validate, and analyze control and user plane interactions as per 3GPP standards.
- Can it emulate both SMF and UPF functions?
- Yes. MAPS™ 5G N4 can independently emulate SMF, UPF, or both simultaneously. This allows for flexible testing, such as validating a real SMF with an emulated UPF, or vice versa.
- What types of PFCP procedures are supported?
- MAPS™ 5G N4 supports a wide range of PFCP messages and procedures, including:
- Session Establishment / Modification / Deletion
- Heartbeat (liveness detection)
- Association Setup / Release
- Usage Reporting
- Session-independent procedures
- Does the emulator support user-plane traffic simulation?
- Yes, user-plane traffic generation and reception (GTP-U) is supported via add-on licenses:
- Mobile Traffic Core - GTP (ETH101) for GTP-U streaming
- Mobile Traffic Core - Gateway (ETH102) for simulating gateway behavior in 5G/LTE
- What testing capabilities are available?
- The emulator supports a wide variety of testing types:
- Functional testing
- Conformance testing
- Regression testing
- Load/stress testing
- Error and negative testing
- Can test cases be customized?
- Yes. MAPS™ 5G N4 provides powerful editors - Message Editor, Script Editor, and Profile Editor - which allow users to customize PFCP messages, session parameters, and call flows as needed.
- Is Automation supported?
- Absolutely. MAPS™ 5G N4 supports automation via command-line interfaces (CLI), Python APIs, and a Scheduler. This makes it ideal for CI/CD integration, remote test execution, and regression testing.
- What’s the licensing model?
- Licensing is modular. The base license includes MAPS 5G N4 interface simulation (PFCP), while user-plane traffic and gateway features are available through additional licenses (ETH101 and ETH102). Contact GL for a tailored quote based on your needs.
- What are the typical use cases?
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- Validating SMF and UPF protocol compliance
- Testing real network elements with emulated peers
- Simulating large UE sessions for performance/load testing
- Debugging and analyzing session and data-plane behavior
- Preparing testbeds for 5G core integration
- Can the emulator work with real DUTs (Devices Under Test)?
- Yes. Users can isolate and test a real SMF or UPF by emulating its peer component and driving realistic PFCP and traffic scenarios.
- Where can I find technical documents or request a demo?
- You can download brochures, view presentations, or request a demo directly from the GL website.
Supported Protocols Standards
Control Plane for N4 Interface
PFCP |
3GPP TS 23.501 (Release 17) |
UDP |
IETF RFC 768 |
IPv4 |
IETF RFC 791 [5] |
IPv6 |
IETF RFC 2460 [6] |
Use Cases
Wraparound Testing of UPF by Emulating SMF with PacketLoad for Data Traffic Evaluation
5G N4 Interface Procedure
In 5G N4 interface, MAPS™ acts as either SMF to test UPF or UPF to test SMF emulating the following call control procedure.
- MAPS™ N4 Emulator supported Procedures are -PFCP Session Establishment Procedure, PFCP Session Modification Procedure, and PFCP Session Deletion Procedure.
Node Related Procedures:
- PFCP Heartbeat
- PFCP Association Setup
- PFCP Association Update
- PFCP Association Release
- PFCP Version Not Supported
- PFCP Node Report
PFCP Session related messages:
- PFCP Session Establishment
- PFCP Session Modification
- PFCP Session Deletion
- PFCP Session Report
5G N4 interface Call Control Procedure
The below screenshots depicts the Call Control Procedure simulation across 5G N4 interface between SMF and UPF.
5G N4 interface Call Control Procedure at SMF Node
(Call Generation)
5G N4 interface Call Control Procedure at UPF Node
(Call Reception)
CLI/API
MAPS™ can be configured as server-side application, to enable remote controlling through command-line based Python client. Python is supported over all protocols as a standard.
The MAPS™ APIs allows for programmatic and automated control over all MAPS™ platforms. Each MAPS™ server can receive multiple client connections and offer independent execution to the client. Likewise, a single client can connect to multiple MAPS™ servers, including servers running different protocols, permitting complex cross-protocol test cases.
Client provides a simple scripting language, with programming facilities such as looping, procedures, and variables. The Client application includes a packaged library that enables communication with the Server from the client environment. The advantage of such communication enables user to control MAPS™ by sending commands and receiving responses in a scripting language already familiar with many users.
The following screenshots depicts transaction of API commands between the Python Client MAPS™ CLI Server.
Sample Python Client
MAPS™ CLI Server
Resources
Note: PCs which include GL hardware/software require Intel or AMD processors for compliance.
| Presentations |
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| MAPS™ 5G N4 Interface Emulator - Presentation |
| MAPS™ 5G Network Emulation Suite - Presentation |
| PacketScan™ 5G Protocol Analyzer Presentation |
| Webinar |
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