Notification System: Requirements and Load

A retail bank's notification system promises its customers three things. A question about a possible fraud on their card is handed to the push and SMS providers within 30 seconds. An alert about money moving in or out of their account is handed to its provider within a minute. An offer from the marketing team never wakes them at night.

It also declines to promise three things. It does not promise that every message arrives exactly once, that an offer arrives at any particular hour of the day, or that a fraud check arrives at all if it is more than 5 minutes old