2.1 Users of the Notification Service Library

Users of the Notification Service library run on cluster nodes as defined by the Cluster

Membership Service (see [4]).

2.1.1 Producer

A notification producer generates notifications (using the Producer API of the Notification


2.1.2 Consumer

A consumer consumes notifications that were generated by producers. If a consumer

is not interested in all notifications, it can specify filter criteria. A consumer can also

be a producer. A consumer can be one of the types described in the following subsections

or both: Subscriber

A subscriber for notifications gets notifications forwarded as they occur (push interface). Reader

A reader retrieves historical notification entries from the persistent notification log

(pull interface).

2.2 Notification Service

Similar to the AIS Services, the Notification Service mainly consists of a client library

and a server. No assumptions are made as to how server instances are distributed

across the nodes of an SA Forum cluster. In an implementation, the server could

even be part of the library.

2.2.1 Notification Service Library

The Notification Service library provides the following public C APIs:

• Producer API

• Subscriber API

• Reader API

2.2.2 Notification Server

The notification server applies the filtering criteria on notifications for delivery to subscribed

consumers and performs the logging into persistent storage.

2.2.3 Transport Service

The transport service links the Notification Service library and the notification server.

It is currently not specified.

2.3 Log Service

Alarm notifications and security alarm notifications are logged persistently. An implementation

may also support persistent logging for the other notification types (object

creation / deletion, attribute value change, state change notifications). It is recommended

that the Notification Service use the API of the SA Forum Log Service to

write notifications into persistent storage. Likewise, the Notification Reader API may

also use the log files of the Log Service.


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