How to build an inexpensive carrier-WiFi network on your laptop with Magma

This Thursday at OpenInfra Summit Berlin, Mirantis network architect Wojciech Nawrot will present a talk, “How to build an inexpensive carrier-WiFi network on your laptop with Magma.” During the session, Wojciech will explain how to build a fully functional carrier-WiFi lab, using gear you probably already have at home plus less than $100 worth of equipment you can easily buy online. This talk is the culmination of innovative work that Wojciech has done over the past two years. If you’re attending the summit this week, check out Wojciech’s session to learn about his fascinating project!

Below we’ve included basic information about Magma, carrier-WiFi, and Wojciech’s carrier-WiFi project. For a deeper dive, including full instructions on how to set up a carrier-WiFi lab, download the project documentation.

Update: The summit has ended. You can watch a recording of Wojciech's presentation below.

Why is carrier-WiFi important?

For those of you who aren’t network engineers, let me explain why this technology is game-changing. For many years, regional mobile operators lacked an affordable solution to decongest LTE networks. This has become a great challenge recently in emerging markets, where mobile operators have experienced tremendous growth in the number of data plan subscribers, but many countries have a shortage of licensed spectrum. This problem has led to network congestion, with service interruptions and degraded Quality of Service for subscribers.

The traditional way to decongest LTE networks is to extend them using costly proprietary solutions that unfortunately are out of reach for most mobile operators in emerging markets. Thus being able to leverage open source Magma to extend LTE networks by seamlessly handing traffic off to carrier-WiFi networks solves a real need in many countries, and directly affects the quality of life for hundreds of millions of people. In his talk, Wojciech shows how you can set up Carrier-WiFi using devices you probably already have at home, combined with less than $100 worth of equipment you can purchase online. This includes a pre-owned enterprise-class WiFi access point, blank USIM cards, Android/iOS phones, a home router, and a single laptop running open source Magma software and a carrier’s core services, such as HSS and PCRF. Magma is an example of open source at its best, bringing innovation to the people and making technology more accessible for everybody.

Note: The remaining content in this blog is an excerpt from Wojciech’s project documentation.

What is Magma software?

Magma is an open source software platform that gives Mobile Network Operators (MNOs) an open, flexible and extendable mobile core network solution. It allows MNOs to offer cellular service without vendor lock-in by providing a modern, open source core network that enables operators who are constrained by a lack of licensed spectrum to add capacity and reach by using WiFi. Magma joined the Linux Foundation in 2021.

What is carrier-WiFi?

Carrier-WiFi is the deployment of a large number of WiFi Access Points in dense geographic areas by a cellular carrier in order to augment its cell phone network. All mobile devices have WiFi, and the capability of offloading cellular traffic to WiFi eliminates cellular congestion. The cellular carrier may also be able to generate additional revenue with a WiFi hotspot plan added on top of the regular LTE data plan.

Phones switch from LTE to WiFi automatically if the carrier’s WiFi network is detected. They authenticate with the carrier’s USIM card and access the Internet according to data plan-specific Policy and Charging Control (PCC) rules. A phone is disconnected from the WiFi network (or the Internet slows down) if the subscriber's data pack for a specific validity period is exhausted. However, for some traffic categories, data usage tracking can be disabled so that specific apps such as Facebook or WhatsApp can be used totally free of charge.

A high-level architecture of the Magma Carrier-WiFi solution integrated with WLAN access network and an MNO’s core elements is shown in the diagram below:

What are the components of a carrier-WiFi lab?

The following diagram shows hardware and software components used in the Lab:

As opposed to typical Magma deployments with eNodeBs and Access Gateways (AGW) implementing Evolved Packet Core (EPC), a Carrier-WiFi Lab doesn’t require expensive LTE RAN equipment operating in licensed spectrum to connect an end-user. Instead, a pre-owned, affordable, enterprise-class WiFi Access Point with 802.1x/EAP-AKA, CoA and L2GRE support can be used. Other hardware peripherals required for the Lab include blank USIM cards, Android/IOS phones (UEs) and a regular home wired NAT router (see 3.4 Hardware specifications of the documentation for details).

The remaining crucial Lab components listed below are implemented as Docker Desktop containers or VirtualBox VMs running on top of the Mac Operating System:

• Magma - Orchestrator (Orc8r) [Docker Desktop@MacOS],

• Magma - Network Management System (NMS) [Docker Desktop@MacOS],

• Magma - Carrier-WiFi Access Gateway (CWAG) [VirtualBox@MacOS],

• Magma - Federation Gateway (FEG) [VirtualBox@MacOS],

• Carrier’s core - Home Subscriber Server (HSS) [Docker@VirtualBox@MacOS],

• Carrier’s core - Policy and Charging Rules Function (PCRF) [VirtualBox@MacOS].

For a description of the respective software components and subcomponents, please download the project documentation.

Thanks for reading! To learn more, please attend Wojciech Nawrot’s presentation at OpenInfra Summit Berlin this Thursday, June 9 and download his full project documentation.