After events or alarms are triggered, SMN can send notifications to specified users by email FunctionGraph (function), or HTTP/HTTPS message. For example, Cloud Trace Service (CTS) detects key cloud service operations and uses SMN to notify you and other users.
If there is a discrepancy between processing capabilities of the upstream and downstream systems, SMN can cache data to reduce downstream pressure to reduce breakdowns, enhance availability, and mitigate complexity in the system.