Used in: cluster-config.


The incoming-message-handler assembles UDP packets into logical messages and dispatches them to the appropriate Coherence service for processing.


The following table describes the elements you can define within the incoming-message-handler element.

Element Required/Optional Description
<maximum-time-variance> Required Specifies the maximum time variance between sending and receiving broadcast Messages when trying to determine the difference between a new cluster Member's system time and the cluster time.

The smaller the variance, the more certain one can be that the cluster time will be closer between multiple systems running in the cluster; however, the process of joining the cluster will be extended until an exchange of Messages can occur within the specified variance.

Normally, a value as small as 20 milliseconds is sufficient, but with heavily loaded clusters and multiple network hops it is possible that a larger value would be necessary.

Default value is 16.
<use-nack-packets> Required Specifies whether the packet receiver will use negative acknowledgments (packet requests) to pro-actively respond to known missing packets. See notification-queueing for additional details and configuration.

Legal values are true or false.

Default value is true.
<priority> Required Specifies a priority of the incoming message handler execution thread.

Legal values are from 1 to 10.

Default value is 7.
<packet-pool> Required Specifies how many incoming packets Coherence will buffer before blocking.

The content override attribute xml-override can be optionally used to fully or partially override the contents of this element with XML document that is external to the base document.