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unexpected dotted line in I/O Graph


Hi, i just wanted to analyse IGMP behavior with I/O Graph with Version 2.0.1. What I got is beside the expected dots for a IGMP event, a dotted line at 0. I tried to change IGMP to 224/8 and changes in Style (Diamant, Block etc) and got always a similar line.

Does anybody has an idea how to remove that "line"?


Sorry, I am not allowed to attach a picture.

asked 13 Jan '16, 04:27

oilman44's gravatar image

accept rate: 0%

can you please upload the image somewhere else (google drive, dropbox) and post the link here?

(19 Jan '16, 07:44) Kurt Knochner ♦
(20 Jan '16, 05:33) oilman44

One Answer:


The Y values of your graph are "packets/s". Subsequently, for those "time intervals" or "ticks" (whose duration can be chosen in logarithmic steps from 0.001 s to 10 min. or so) where there wasn't any packet matching the filter rule, the corresponding Y value of "packets/s" is 0.

You can see that the fat red line at Y=0 becomes narrower at time ticks where Y value differs from 0 and so the dot for that interval is placed elsewhere. In your case, it is best visible shortly after 120 s time where you had two intervals with Y = 1 packet/s in two cases.

You may like the picture more if you change the graph style from "Dot" to "Impulse" for this kind of packets which occur only now and then.

I don't know, however, any setting which would allow you to specify that zero Y-values should not be drawn if Dot, Diamond or any other "discrete" style is used.

answered 20 Jan '16, 05:54

sindy's gravatar image

accept rate: 24%

edited 20 Jan '16, 15:32