TOSSI - Telecom Open Source System Integrator
Open telecom, made whole.
TOSSI is the Neutral Foundation for the Open Telecom Stack, built on Open Standards and Open-Source Innovation. We believe technology is strongest when it is whole, uniting Radio, RAN, Core, AI, and Security into an Open, Interoperable, and Enduring Ecosystem.
A Linux distribution for open telecom
A Linux distribution doesn't invent the kernel or every package. It curates the best technologies, ensures they work together, and delivers a system people can trust. TOSSI brings that same approach to telecom, integrating and validating open technologies so builders can focus on innovation, not integration.
Make telecom open - and make it work as one
Telecom runs the modern world, yet for decades it stayed closed. TOSSI exists to change that - to integrate the open telecom stack into a complete, validated, secure network that any operator, nation, or builder can run on open foundations.
The question is no longer whether open source can build a network - there are capable open-source projects for the core, the radio, the RIC and the dataplane. The unsolved problem is making the pieces work together: conformant to the standards, secured end to end, and reproducible in production.
That integration is what turns a pile of excellent projects into a network you can trust. We do it once, in the open - so the community starts from interoperability instead of integration debt, and the next decade of telecom rests on foundations no single vendor can close again. And because a network built today must stay safe for a decade, post-quantum security is woven through every interface from the start.
Eight pillars, one integrated stack
Each pillar is a layer of the open telecom system. TOSSI selects, versions, integrates, and validates them so they interoperate end to end.
5G Core Network
Cloud-native, service-based 5GC: control plane and user plane, 3GPP-aligned.
RAN & O-RAN Integration
Disaggregated, multi-vendor radio over open fronthaul and the O-CU/O-DU/O-RU split.
RAN Intelligent Controllers
Near-RT and Non-RT RIC control loops over the E2 and A1 interfaces.
Service Management & Orchestration
The management plane terminating O1, O2, and A1 across the deployment.
xApps & rApps
The RAN-control app ecosystem with SDKs, descriptors, and onboarding.
Post-Quantum Security
ML-KEM, ML-DSA, and SLH-DSA with crypto-agility across TLS, IPsec, and PKI.
Cloud-Native & Kubernetes Operators
The Kubernetes substrate and GitOps that package and lifecycle telecom CNFs.
eBPF & Dataplane
Kernel-programmable networking and a high-throughput UPF dataplane via eBPF/XDP.
Open, reproducible, and secure by default
What TOSSI is
- A neutral, vendor-independent integrator
- Upstream-first - fixes land in the source projects
- Conformance against 3GPP and O-RAN Alliance specifications
- Post-quantum, crypto-agile security by default
What TOSSI is not
- A vendor or a product company
- A hard fork of upstream projects
- A single project - it is the integration of many
- A replacement for 3GPP or the O-RAN Alliance
Build the integrated open telecom stack with us
Start with the reference architectures, bring your network function or app to conform against the baseline, or join the working groups shaping where the stack goes next.