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Throughput graph: Why are there parallel lines?

0

Hello,

This is my throughput graph: alt text Could anyone tell me what I can conclude about the 2 parallel lines in this graph? Thanks in advance.

asked 19 Jun '11, 09:18

ord's gravatar image

ord
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2 Answers:

2

I see more that 2 parallel lines, but I assume you mean the two most "thick" ones. They tell you that most of he time, you have an average throughput of ~11.25 or ~11.75 MByte/s. So this looks like a healthy and fully utilized 100Mbit/s network.

You can zoom in on the graph to get more detail...

answered 19 Jun '11, 14:32

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SYN-bit ♦♦
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edited 20 Jun '11, 11:39

Guy%20Harris's gravatar image

Guy Harris ♦♦
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Hmmm... thinking about this for a second time, I can't tell from the graph that the network is healthy, I can only tell from it that Wireshark sees near 100Mbit/s bandwidth.

(which can easily be the case when a Gbit/s link gets spanned to a 100Mbit/s span port)

(19 Jun '11, 20:36) SYN-bit ♦♦

Hi SYNbit,

Thanks a lot. Actually, this is the case we've done with 2 PCs transmitting data to each other over a direct 100Mbps link. I've already zoomed in the graph and seen that in fact, there's nothing parallel but many dots together :)

BR,

(20 Jun '11, 00:17) ord

0

Hello,

Can I ask you another question about the throughput graph? Following is my another graph: alt text

Capacity of the link is 100Mbps; however, you can see the throughput can reach around 1Gbps at some time. Is there any inconsistency?

BR,

answered 20 Jun '11, 08:19

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ord
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I can imagine this being caused by in-accurate timestamping. When your capturing device is busy, it might queue a couple of packets and when it gets to timestamp them, they might get (almost) the same timestamps. Have a detailed look at the packets at the spike to see whether this is the case...

(20 Jun '11, 20:36) SYN-bit ♦♦