This diagram shows how BEMS uses Microsoft Graph to send notifications to devices when a reverse proxy is used. BlackBerry recommends using a reverse proxy.

Component name	Description
BEMS	BEMS consolidates several BEMS services used to send work data to and from BlackBerry Dynamics apps, including BlackBerry Push Notifications (BlackBerry Mail), BlackBerry Connect, BlackBerry Presence, and BlackBerry Docs. BEMS listens for notification URI sent by the Microsoft Graph API.
Reverse proxy server	The reverse proxy server receives the Microsoft Graph connection and proxies the connection to the private BEMS URI.
Microsoft Graph	Microsoft Graph is a RESTful web API that allows you to communicate with Microsoft Cloud service resources.

1. BEMS sends a request to Microsoft Graph to subscribe to mailbox changes (for example, new email). The External Notification URL is included in the request.
2. Microsoft Graph initiates a connection to your organization's reverse proxy using the External Notification URL and sends a request that includes notification details.
3. The reverse proxy server intercepts the Microsoft Graph connection request and translates/routes the request to your BEMS cluster or instance.
4. BEMS receives the request from the reverse proxy and sends the new notification (for example, new email) to BlackBerry Work based on the notification rules and the user's device settings.