TCP/IP hiccups

I’m working on a closed system consisting of three nodes connected via
Ethernet (100Mbit). One node constantly sends data (GPS, etc.) on a TCP/IP
port. The node in the middle receives and buffers the data and periodically
passes it on to the third node.

The middle node’s TCP/IP reads consistently take about .02 seconds. However,
every now and then, a read will take .5 or even >1 second. This happens even
if I stop communication to the third node, so there should be very little,
if any, interference from anything else. (The receiving process is high
priority and is dedicated to the data port. It performs no sends, i.e., it
stuffs the data into shared memory.)

Running QNX 4.24 but Socket 4.25.

Any ideas for diagnosing this anomaly would be appreciated :slight_smile: