Used in: packet-publisher.


The traffic-jam element is used to control the rate at which client threads enqueue packets for the Packet publisher to transmit on the network. Once the limit is exceeded any client thread will be forced to pause until the number of pending packets drops below the specified limit. To limit the rate at which the Publisher transmits packets see the burst-mode element.


Specifying a limit which is to low, or a pause which is to long may result in the publisher transmitting all pending packets, and being left without packets to send. An ideal value will ensure that the publisher is never left without work to do, but at the same time prevent the queue from growing uncontrollably. It is therefore recommended that the pause remain quite short (singles of milliseconds), and that the limit on the number of packets be kept high (i.e. > 5000).


The following table describes the elements you can define within the traffic-jam element.

Element Required/Optional Description
<maximum-packets> Required Specifies the maximum number of pending packets that the Publisher will tolerate before determining that it is clogged and must slow down client requests (requests from local non-system threads). Zero means no limit. This property prevents most unexpected out-of-memory conditions by limiting the size of the resend queue.

Default value is 8192.
<pause-milliseconds> Required Number of milliseconds that the Publisher will pause a client thread that is trying to send a message when the Publisher is clogged. The Publisher will not allow the message to go through until the clog is gone, and will repeatedly sleep the thread for the duration specified by this property.

Default value is 4.