Update tutorial-nested-iot-edge.md

Author: huguesBouvier

articles/iot-edge/tutorial-nested-iot-edge.md

@@ -254,7 +254,7 @@ In the [Azure Cloud Shell](https://shell.azure.com/), you can take a look at the
 
 In addition the runtime modules **IoT Edge Agent** and **IoT Edge Hub**, the **top layer device** receives the **Docker registry** module and **IoT Edge API Proxy** module.
 
-The **Docker registry** module points to an existing Azure Container Registry. In this case, `REGISTRY_PROXY_REMOTEURL` points to the Microsoft Container Registry. In the `createOptions`, you can see it communicates on port 5000.
+The **Docker registry** module points to an existing Azure Container Registry. In this case, `REGISTRY_PROXY_REMOTEURL` points to the Microsoft Container Registry. By default, **Docker registry** listens on port 5000.
 
 The **IoT Edge API Proxy** module routes HTTP requests to other modules, allowing lower layer devices to pull container images or push blobs to storage. In this tutorial, it communicates on port 443 and is configured to send Docker container image pull requests route to your **Docker registry** module on port 5000. Also, any blob storage upload requests route to module AzureBlobStorageonIoTEdge on port 11002. For more information about the **IoT Edge API Proxy** module and how to configure it, see the module's [how-to guide](how-to-configure-api-proxy-module.md).