SQL Server Notification Services Architecture

This diagram shows the basic SQL Server Notification Services (SSNS) components. At the top, subscribers use a browser to set their notification preferences in a subscription application, which loads those preferences into tables in SQL Server.

On the left, applications generate various types of events, which are picked up by SSNS’s Event Provider. The Event Provider formats the events, accumulates them into batches, and loads them into SQL Server. The Generator uses information from the subscription tables to build and send queries to SQL Server, which generates a table of raw notifications. The Distributor reads the raw notifications, transforms them into XML, applies Extensible Stylesheet Language Transformations (XSLT) style sheets for the appropriate devices, and routes them to the various distribution channels shown on the right.

The distribution channels deliver the notifications to the subscriber’s devices, where they can be presented to the user in various ways, such as e-mail messages, instant messages, SMS messages, or even text-to-speech messages on a phone.