Notify

ENS notifies its subscribers of an event by sending a notification. Notify is also referred to as “publish.” A notification can contain the following items:

• An event reference (which, optionally, can contain parameter/value pairs)

• Optional application-specific data (“opaque” for ENS, but the publisher and subscriber agree apriori to the format of the data)

The optional application-specific data is referred to as the “payload.”

There are two kinds of notifications:

• Unreliable notification - Notification sent from an event publisher to a notification server. If the publisher does not know nor care about whether there are any consumers, or whether they get the notification, this request does not absolutely need to be acknowledged. However, a publisher and a subscriber, who are mutually aware of each other, can agree to set up a reliable event notification link (RENL) between themselves. In this case, once the subscriber has processed the publisher’s notification, it sends an acknowledgment notification back to the publisher.

• Reliable notification - Notification sent from a server to a subscriber as a result of a subscription. This type of notification should be acknowledged. A reliable notification contains the same attributes as an unreliable notification.

See Publisher API for more information.