QoS stands for Quality of Service. It consists of several parameters that control message communication behavior between the Data Capture and Delivery controller and WebSphere® Premises Server.
The default configuration for the Data Capture and Delivery controller is QoS level: QOS 1 and QoS persistence: memory only. This means that messages, including tag reads, are assured to flow from the Data Capture and Delivery controller to WebSphere Premises Server, except when the Data Capture and Delivery controller has been turned off, the Data Transformation has been stopped during network outages, or WebSphere Premises Server is down.
Reasons for these default settings:
Tag reads eventually flow to the back end, as long as the Data Capture and Delivery controller is not rebooted or restarted, regardless of network communications between the Data Capture and Delivery controller and WebSphere Premises Server. Tags cannot be read or queued at all when the network between the tag reader and the Data Capture and Delivery controller is down because there is no quality of service supported by the tag reader protocols.
At the Data Capture and Delivery controller, there are three QoS levels at which messages can be configured to be delivered from the Data Capture and Delivery controller to WebSphere Premises Server:
Persistence is configured through the persistence property key in the MicroBroker agent. The values for the persistence property align with the QoS levels 0, 1, and 2.
There are two ways to configure persistence on the Data Capture and Delivery controller:
<property key="qos" value="1" required="false" default="1" name="QoS" description="Messaging Quality of Service: 0-at most once, 1-at least once, 2-exactly once."/>
<property key="qos.cutoff" value="warning" default="warning" name="QoS Threshold Cutoff" description="Lowest threshold level before assuming QoS=0. Threshold levels that are equal to or higher than this value will be published at the agent-defined QOS level."/>Since the value is set to warning, all alerts of level warning and above (for example, warning and error alerts) will be published at the QoS level defined for the alert agent. Levels below warning (for example, info and debug alerts) will be published at the qos=0 level.