AetherSlice

AetherSlice is an automated 5G SA network slicing testbed for Kubernetes. It deploys a 5G core with Open5GS and RAN options based on srsRAN Project, UERANSIM, or srsRAN with real RF hardware.

Developed as part of a project at the Chair "Architekturen der Vermittlungsknoten", Technische Universität Berlin, Germany.

Project Information

Field	Information
Project name	AetherSlice
Initial authors	Lukas Banjamin Roth, Johannes Maria Ruef
Supervisor	Elena-Ramona Modroiu
License	GNU Affero General Public License v3.0 (AGPLv3), see LICENSE

Basic Build/Run Instructions

Install the Python and Ansible dependencies on the control machine:

pip install -r requirements.txt
ansible-galaxy collection install -r ansible/requirements.yml

Edit ansible/inventory/hosts.yml with the target node IPs, then deploy the full stack:

cd ansible
ansible-playbook deploy.yml -i inventory/hosts.yml

To redeploy only the 5G stack on an existing Kubernetes cluster:

ansible-playbook deploy.yml --tags 5g -i inventory/hosts.yml

Architecture

┌─ K8s Cluster ─────────────────────────────────────────────────────┐
│                                                                   │
│  master (192.168.178.110)          worker (192.168.178.111)       │
│  ┌─────────────────────┐          ┌─────────────────────────┐    │
│  │ Open5GS Core (5GC)  │          │ Container image builds  │    │
│  │  AMF, NRF, SCP,     │          │ (nerdctl + buildkit)    │    │
│  │  AUSF, UDM, UDR,    │          └─────────────────────────┘    │
│  │  PCF, NSSF, BSF     │                                         │
│  │  SMF×3 (per slice)  │          ┌─────────────────────────┐    │
│  │  Shared UPF          │          │ RAN (srsRAN or UERANSIM)│    │
│  │  MongoDB, WebUI     │          │  gNB + 3 UEs (ZMQ)     │    │
│  └─────────────────────┘          └─────────────────────────┘    │
│                                                                   │
│  Calico CNI + Multus (PFCP bridge for SMF↔UPF)                   │
└───────────────────────────────────────────────────────────────────┘

Network Slices

Slice	S-NSSAI	5QI	DNN	gNB min PRB	gNB max PRB	UE Subnet
Best Effort	SST=1, SD=1	9	internet	10%	100%	10.41.0.0/16
Priority	SST=1, SD=2	5	priority	25%	80%	10.42.0.0/16
Guaranteed	SST=4, SD=3	6	guaranteed	40%	80%	10.43.0.0/16

QoS differentiation is enforced by the gNB scheduler via per-slice PRB allocation. A single shared UPF handles all slices (no per-slice traffic shaping).

Software Versions

Component	Version
Open5GS	v2.7.5
srsRAN Project (gNB)	latest main
srsRAN 4G (srsUE)	release 25.10
UERANSIM	3.2.6
Kubernetes	1.29
Calico	3.27.0
Multus CNI	4.0.2
Ubuntu	22.04 LTS

Requirements

Control Machine (runs Ansible)

• Ansible >= 2.15
• SSH key at ~/.ssh/id_ed25519

Cluster Nodes

Two VMs (or bare-metal machines) with Ubuntu 22.04, root SSH access, and static IPs. In development, both VMs were in the same local network, if this is not the case, also join them together via a VPN or other methods.

Node	Role	Recommended	Minimum
k8s-master	Core network (Open5GS)	4 vCPU, 8 GB RAM	2 vCPU, 4 GB RAM
k8s-worker	Image builds + RAN pods	14 vCPU, 16 GB RAM	8 vCPU, 8 GB RAM

The worker needs significant CPU for the srsRAN deployment: gNB (~6 cores), GNU Radio broker (~1.5 cores), and 3 UEs (~1.4 cores each). With fewer than 8 cores, UE attachment may be unreliable.

Inventory

Edit ansible/inventory/hosts.yml with your node IPs:

k8s_nodes:
  hosts:
    k8s-master:
      ansible_host: 192.168.178.110
      k8s_role: master
    k8s-worker:
      ansible_host: 192.168.178.111
      k8s_role: worker

Deployment

Full Stack (first time)

cd ansible
ansible-playbook deploy.yml -i inventory/hosts.yml

This runs all stages in order:

1. nodes -- K8s prerequisites on all nodes (containerd, kubelet, kernel modules, sysctl)
2. cluster -- Initialize K8s master, join workers, install Calico CNI
3. images -- Build container images on worker (Open5GS, srsRAN gNB, srsUE)
4. 5g -- Deploy core network + RAN

Selective Tags

# Only deploy K8s prerequisites
ansible-playbook deploy.yml --tags nodes -i inventory/hosts.yml

# Only deploy 5G stack (assumes cluster is ready)
ansible-playbook deploy.yml --tags 5g -i inventory/hosts.yml

# Only redeploy RAN
ansible-playbook deploy.yml --tags ran -i inventory/hosts.yml

RAN Simulator Options

The default RAN is srsRAN with ZMQ (3 simulated UEs). Switch with -e ran_simulator=:

Option	Command	Description
srsran (default)	deploy.yml --tags 5g	srsRAN gNB + 3 srsUE via GNU Radio ZMQ broker. Full L1/L2 radio simulation with QoS differentiation.
ueransim	deploy.yml --tags 5g -e ran_simulator=ueransim	UERANSIM gNB + 2 UEs. Faster startup, no radio layer (no QoS differentiation in throughput).
srsran_rf	deploy.yml --tags 5g -e ran_simulator=srsran_rf	srsRAN gNB with USRP B210 for real phones. Requires SDR hardware. See docs/real-rf-setup.md.

srsRAN (ZMQ) -- Default

Deploys a single pod on the worker with 5 containers: gNB, GNU Radio broker, and 3 srsUEs. Each UE connects to a different slice. Startup takes ~5 minutes (UEs attach sequentially at 130s, 160s, 190s).

ansible-playbook deploy.yml --tags 5g -i inventory/hosts.yml

UERANSIM

Deploys UERANSIM gNB + 2 UEs. No radio layer simulation -- useful for testing core network routing and slice selection without the CPU overhead of srsRAN.

ansible-playbook deploy.yml --tags 5g -i inventory/hosts.yml -e ran_simulator=ueransim

Real RF

Deploys only the gNB on a laptop connected to a SDR. Real 5G phones connect over the air (band n78, 3.6 GHz). The laptop is automatically provisioned as a lightweight K8s worker. This is not yet tested and may still need significant development work

ansible-playbook deploy.yml --tags 5g -i inventory/hosts.yml -e ran_simulator=srsran_rf

See docs/real-rf-setup.md for hardware, SIM programming, and phone setup.

Verification

# All pods running
kubectl get pods -n open5gs

# UE connectivity (srsRAN ZMQ)
kubectl exec -n open5gs deployment/srsran-multi-ue -c ue1 -- ping -c 3 8.8.8.8
kubectl exec -n open5gs deployment/srsran-multi-ue -c ue2 -- ping -c 3 8.8.8.8
kubectl exec -n open5gs deployment/srsran-multi-ue -c ue3 -- ping -c 3 8.8.8.8

# gNB logs (should show "NG Setup procedure is successful")
kubectl logs deployment/srsran-multi-ue -n open5gs -c gnb | grep "NG Setup"

# Open5GS WebUI
# http://<master-ip>:30300  (admin / 1423)

QoS Benchmark

Run the pairwise contention benchmark to verify per-slice QoS differentiation:

./ansible/scripts/contention_benchmark.sh

Tests all 3 UE pairs competing for radio resources. Expected result under contention:

UE1 vs UE2:  1.58 vs 2.99 Mb/s  (35% vs 65%)
UE1 vs UE3:  1.58 vs 5.99 Mb/s  (21% vs 79%)
UE2 vs UE3:  3.04 vs 5.98 Mb/s  (34% vs 66%)

Key Files

File	Description
ansible/deploy.yml	Main playbook
ansible/inventory/hosts.yml	Cluster node IPs
ansible/roles/srsran/files/multi-ue.yaml	gNB config, UE configs, GNU Radio flowgraph, K8s deployment
ansible/roles/srsran/files/subscribers.yaml	Open5GS subscriber provisioning (3 UEs)
ansible/roles/open5gs_srsran/files/	All Open5GS NF manifests (AMF, SMF, UPF, etc.)
ansible/scripts/contention_benchmark.sh	Pairwise QoS benchmark script
docs/real-rf-setup.md	USRP B210 + phone setup guide

Redeployment Notes

• If subscriber config changes, delete the job first: kubectl delete job add-subscribers -n open5gs
• srsRAN uses Recreate deployment strategy to avoid rollout hangs
• The --tags ran tag redeploys only the RAN (with automatic cleanup of previous deployment)
• Monitoring stack (Prometheus + Grafana): --tags monitoring (Grafana at :30301, admin/admin5g)