UNIX NETWORK PROGRAMMING Volume1. p.97

Figure 4.9 shows the actual number of entries on each queue measured on a moderately busy Web server. These values were obtained by sampling these two counters for a listening HTTP socket approximately every 84 ms for 2 hours during the middle of a weekday.

#entries on queue	Incomplete queue	Complete queue
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34	3,033 7,158 10,551 12,960 11,949 9,836 7,754 6,165 4,829 3,687 2,674 1,893 1,431 1,083 1,065 980 784 696 514 382 294 248 161 152 121 77 48 33 79 78 90 70 29 16 4	90,358 107 59 52 38 27 31 22 30 35 30 25 29 25 49 7
	90,924	90,924

Figure 4.9 Number of enties on incomplete and completed connection queues.

The completed connection queue was empty 99.4% of the time, but there were periods when this queue was not empty. The system on which this server was running (BSD/OS 2.0.1) had a maximum backlog of 64, although the values shown do not appear to have reached this limit.