# Overview

> The Road Roaming Hub is a standalone OCPI hub that connects CPOs, eMSPs and CPMS platforms, so each integrates once and reaches the whole network.

The Road Roaming Hub is a standalone, multi-tenant OCPI hub. It connects Charge Point Operators (CPOs), eMobility Service Providers (eMSPs) and CPMS platforms to each other, so each one integrates once and reaches every network on the hub. It works alongside the Road Charge Point Management System (CPMS) but is a product in its own right: you connect over OCPI, whatever platform you run.

There are three ways to use it.

**Roaming-as-a-Service.** Connect and use Road's existing roaming agreements instead of building your own. A CPO reaches the drivers of every eMSP on the network; an eMSP reaches every location. This suits an operator that wants coverage without negotiating agreements one at a time. See [joining as a CPO](/docs/roaming/guides/joining-as-a-cpo) and [joining as an eMSP](/docs/roaming/guides/joining-as-an-emsp).

**Network extension.** A CPMS that already runs its own roaming connects to the hub as one more link and gains the locations and drivers in Road's network, through a single integration, on top of the agreements it already holds.

**Roaming infrastructure.** Connect over OCPI and run your roaming transactions on the hub while keeping full ownership of your own agreements. This is the basis of [Roaming PaaS](/docs/roaming/guides/roaming-paas), where you run your own roaming network on Road's platform.