Used in: cluster-config.


Specifies configuration information for the Packet publisher, which manages network data transmission.

Reliable packet delivery

The Packet publisher is responsible for ensuring that transmitted packets reach the destination cluster node. The publisher maintains a set of packets which are waiting to be acknowledged, and if the ACK does not arrive by the packet-delivery resend timeout, the packet will be retransmitted. The recipient node will delay the ACK, in order to batch a series of ACKs into a single response.


The rate at which the publisher will accept and transmit packet may be controlled via the traffic-jam and packet-delivery/flow-control settings. Throttling may be necessary when dealing with slow networks, or small packet-buffers.


The following table describes the elements you can define within the packet-publisher element.

Element Required/Optional Description
<enabled> Required Specifies if TCMP clustering is enabled. For Coherence editions which support both Coherence Extend and Coherence TCMP based clustering, this feature allows TCMP to be disabled to ensure that a node only connects via the Extend protocol.

Default value is true.

Preconfigured override is tangosol.coherence.tcmp.enabled.
<packet-size> Required Specifies the UDP packet sizes to utilize.
<packet-delivery> Required Specifies timing parameters related to reliable packet delivery.
<notification-queueing> Required Contains the notification queue related configuration info.
<burst-mode> Required Specifies the maximum number of packets the publisher may transmit without pausing.
<traffic-jam> Required Specifies the maximum number of packets which can be enqueued on the publisher before client threads block.
<packet-buffer> Required Specifies how many outgoing packets the OS will be requested to buffer.
<packet-pool> Required Specifies how many outgoing packets Coherence will buffer before blocking.
<priority> Required Specifies a priority of the packet publisher execution thread.

Legal values are from 1 to 10.

Default value is 6.

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.