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#1625 - 05/20/06 02:43 PM Graph Interpretation
Galaxiana Offline


Registered: 05/20/06
Posts: 7
Loc: Chicago, IL
I am trying to understand what some of the data in Ping Plotter means. I have posted a screenshot of the graphs I get for a problem I'm trying to troubleshoot. Comcast should be out here today to address the problem evident in the first and second graphs, but what is causing the curious repetitive pattern on the 5th and 6th graphs?

Also, what is happening in the bottom (7th) graph? How would I go about resolving this problem (if it is one), since it's not my own (or my game site's) ISP, but somewhere in between?

The graphs display a 12 hour period of 15-second interval traceroutes.

Thank you in advance for your help.

Susan


Attachments
1646-Graph-Question.png


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#1626 - 05/20/06 03:51 PM Re: Graph Interpretation [Re: Galaxiana]
Pete Ness Offline



Registered: 08/30/99
Posts: 1106
Loc: Boise, Idaho
Hi, Susan.

Actually, there is less problem here than you might think there is.

The general technique for use of PingPlotter is to look at the final hop (or the last hop that is responding well, if the final destination isn't available like what you're seeing in the attached graph). If you see problems at that hop, then look back to earlier hops to find out the culprit for those problems. Any problems that occur at any intermediate hops that do not appear at the final destination, though, are non-issues.

Most of the graph problems we see hare are probably (I can't say for sure since you didn't turn on the time graph for hop 10), are not at the final destination. The "jitter" you see at hop 8 doesn't look like it shows up at hop 9 or 10, so that's an oddity of hop 8. The packet loss at hop 2 doesn't show up at hop 4, so that's an artifact of hop 2 that isn't affecting your downstream experience.

We talk about this technique here:

http://www.nessoft.com/kb/47

Also, we talk about how intermediate hop performance doesn't matter here:

http://www.nessoft.com/kb/24

Honestly, I don't see an obvious problem in the graph you attached. I'd want to see the graph of hop 10 (and ideally, I'd turn on TCP packets and try and get a trace graph of uswest.battle.net port 6112), but it looks pretty good.

Also, you'll want to correlate problems with "incidents" (lag, dropped connections, etc) - we discuss that in the first article listed above.

- Pete

Hop 8 (12.123.13.174) is showing some jitter, but

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#1627 - 05/20/06 05:34 PM Re: Graph Interpretation [Re: Galaxiana]
Galaxiana Offline


Registered: 05/20/06
Posts: 7
Loc: Chicago, IL
Pete,

You are so amazing, the sheer amount and quality of time you spend helping users interpret the results they get with your incredible programs! I mean, support for technical issues is one thing, but you go so far beyond the norm. I, for one, greatly appreciate your help, as I'm sure many others do, too.

I didn't post the hop 10 graph because it looked fine, even and consistent ~54 ms pings. As for the packet loss on hop 2, Comcast came out today, inspected and tested the cabling, and said the squirrels have been nibbling on it! They will replace it Tuesday.

I have PingPlotter running TCP packet pings now to uswest.battle.net port 6112. My route is actually going one hop further now past the previous end (which doesn't return ICMP packets.) But what's REALLY curious is, every so often another hop opens up between 11 and 12, and shows there for a few seconds with 100% packet loss, and then the hop disappears again. It always appears between hops 11 and 12. I'm trying to get a screenshot of this. No IP address shows up on this one, just the extra hop for a few seconds. Have you ever seen this before? Do you know what causes it?

Thank you,
Susan
_________________________
In Diablo II, as in real life, death is something you should strive to avoid. - Official Diablo website

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#1628 - 05/20/06 06:41 PM Re: Graph Interpretation [Re: Galaxiana]
Pete Ness Offline



Registered: 08/30/99
Posts: 1106
Loc: Boise, Idaho
Those "route changes" are all captured by PingPlotter - there's no need for you to capture it with a screenshot.

Just save off your data (File -> Save Sample Set...) and then email that to [email]support@pingplotter.com.[/email] We'll have a look and see if there's anything interesting there. If you're getting a lot of packet loss at the final destination, this might happen, but we'll know more if we look at the data.

- Pete

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