L25GC+: A Low-latency, 3GPP-compliant 5G Core Network

About

L25GC+ is a re-architected 5G Core (5GC) that reduces latency and improves user experience by minimizing control plane impact on the data plane and optimizing packet processing. Built on free5GC and OpenNetVM, L25GC+ uses X-IO to eliminate message serialization and HTTP overheads in 3GPP SBI, enabling fast, synchronous communication between NFs. L25GC+ integrates with free5GC NFs via compatible SBI APIs from X-IO, easing adoption with minimal code changes. In testbed evaluations, L25GC+ achieves 2× lower data plane latency during paging and handover compared to free5GC.

For more design details, please refer to:

• SIGCOMM 2022: L25GC: A Low Latency 5G Core Network based on High-Performance NFV Platforms
• CloudNet 2023: L25GC+: An Improved, 3GPP-compliant 5G Core for Low-latency Control Plane Operations

Build and Installation

• Tested OS: See Tested OS Distributions

• NIC Requirement: You need at least two DPDK-compatible NICs to run L25GC+.

• Reference topology:

Experiment Setup

1. Configure N2, N3, and UPF-U on the CN node.
2. Configure UERANSIM on the UE/AN node.
3. Update IP routes and ARP settings in scripts/set_nw_env.sh for both UE/AN and DN nodes.
4. Refer to our setup guide and instructional video for step-by-step instructions.

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Installation

1. Run the setup script on target machine

   ./scripts/setup.sh <ue|cn|dn>

2. NIC interface on CN node must be bound to a compatible DPDK driver (e.g., igb_uio).

   Note: In some environments, the interface must be brought down before binding.

   sudo ifconfig <interface> down
   sudo ~/L25GC-plus/NFs/onvm-upf/subprojects/dpdk/usertools/dpdk-devbind.py -s
   sudo ~/L25GC-plus/NFs/onvm-upf/subprojects/dpdk/usertools/dpdk-devbind.py -b igb_uio <PCIe addr>

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Running L25GC+

You can use our provided scripts to launch onvm_mgr and L25GC+ NFs. This script assumes the L25GC-plus folder is your working directory.

1. Run ONVM Manager

   ./scripts/run/run_onvm_mgr.sh

2. Run UPF-U (new terminal)

   ./scripts/run/run_upf_u.sh 1 ./NFs/onvm-upf/5gc/upf_u_complete/upf_u.txt

3. Run UPF-C (new terminal)

   ./scripts/run/run_upf_c.sh 2 ./NFs/onvm-upf/5gc/upf_c_complete/config/upfcfg.yaml

4. Run 5GC Network Functions (NFs) (new terminal)

   source ~/.bashrc
   ./scripts/run/run_cp_nfs.sh

5. Run Webconsole (new terminal)

   The webconsole is used to pre-store UE info in MongoDB for authentication and configure QoS.

   cd webconsole/ 
   ./bin/webconsole

   See this video or doc for usage instructions.
6. Stop L25GC+

   ./scripts/run/stop_cn.sh

Running UERANSIM

This script assumes the L25GC-plus/UERANSIM folder is your working directory.

1. Run gNB

   ./build/nr-gnb -c config/free5gc-gnb.yaml

2. Run UE (new terminal)

   sudo ./build/nr-ue -c config/free5gc-ue.yaml

Unit test

1. Ping Test (UE to DN)

   # on UE/RAN node
   ping -I uesimtun0 192.168.1.4

   Replace 192.168.1.4 with the IP of your DN node.

2. iperf3 Throughput Test

   # On DN Node:
   iperf3 -s -B 192.168.1.4

   # On UE/RAN Node:
   iperf3 -c 192.168.1.4 -B 10.60.0.1

   Replace 192.168.1.4 with the IP of your DN node. Assume 10.60.0.1 is the IP of UE (uesimtun0).

Tested OS Distributions

OS Distribution	Status	Notes
Ubuntu 24.04	⚠️ Untested	All dependencies available via apt or pip
Ubuntu 22.04	✅ Works out of the box	All dependencies available via apt or pip
Ubuntu 20.04	✅ Works out of the box	All dependencies available via apt or pip
Ubuntu 18.04	⚠️ Untested	Likely requires upgrading GCC, Python, and installing recent Meson manually

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Dependency Versions

Component	Version	Installation Notes
DPDK	24.07.0	Built from source using Meson
Pktgen-DPDK	24.07.0	Compatible with the same DPDK version
dpdk-kmods	commit@9b182be	Required only for igb_uio (optional)
Meson	>=0.58.0	Recommended: 0.61.2+; use pip3 install meson
Ninja	>=1.10.0	Usually installed via apt

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Submodules in L25GC-plus/NFs/

The NFs/ directory contains X-IO and all the L25GC+ NFs.

Module	Description	Language	Commit
amf	Access and Mobility Management Function — handles UE registration and mobility	Go	a186198
ausf	Authentication Server Function — performs UE authentication procedures	Go	0cb2ece
chf	Charging Function — manages charging-related interfaces (if implemented)	Go	088bd10
nrf	Network Repository Function — supports service registration/discovery	Go	e4c12be
nssf	Network Slice Selection Function — selects network slice per UE session	Go	a6b6472
onvm-upf	User Plane Function — data plane packet handling implemented via ONVM	C	f4423e8
pcf	Policy Control Function — enforces policy rules for QoS, access, charging	Go	1de2b6c
smf	Session Management Function — handles PDU sessions and tunnel setup	Go	fbb1e3e
udm	Unified Data Management — manages user identity and subscription access	Go	147cabe
udr	Unified Data Repository — stores structured user data	Go	fce77b3
xio	Unified I/O interface between Golang NFs and ONVM stack	Go/C	464d9d5

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New feature

• QoS implementation is achieved using token bucket and trTCM to support GBR and MBR.
• You can view the content and QoS settings through the following link:
  1. QoS Configuration in Webconsole.
  2. QoS Design Document

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Contact

For questions, feedback, or collaboration inquiries:

Email: l25gc@googlegroups.com
Join our Google Group

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License

L25GC+ is released under the Apache 2.0 License.