The onstat -g ntu option prints network user statistics.
IBM Informix Dynamic Server Version 10.00.UC1 -- On-Line -- Up 01:57:53 -- 101376 Kbytes global network information: #netscb connects read write q-free q-limits q-exceed alloc/max 3/ 3 0 0 0 1/ 1 135/ 10 0/ 0 2/ 0 Individual thread network information (basic): netscb type thread name sid fd poll reads writes q-nrm q-pvt q-exp c76ea28 tlitcp ontape 61 3 5 0 0 0/ 0 1/ 1 0/ 0 c63e548 tlitcp tlitcplst 4 1 5 0 0 0/ 0 0/ 0 0/ 0 c631028 tlitcp tlitcppoll 3 0 5 0 0 0/ 0 0/ 0 0/ 0