Need help interpreting graphs from SmokePing

chernavsky
chernavsky used Ask the Experts™
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I recently installed SmokePing on a server at work, so that I could monitor the state of our Internet connection to the cloud providers we use.  However, I'm having some trouble figuring out the meaning of the graphs that SmokePing generates.  For example:

http://chernavsky.dreamhosters.com/temp/smokeping.jpg

These five graphs cover the same 24-hour time period.  The bottom-right host (labeled "Frontier") is the next hop after our default gateway.  The other four hosts correspond to four cloud services we use.

What might cause the transient hump to appear for three hosts, but not the other two?  Also, what might cause the small, sudden step-wise increase in latency, followed by a decrease later?  Finally, is this type of behavior fairly normal, or is something amiss?
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Top Expert 2016

Commented:
caching  maybe why the delay and the subsequent decrease.  To all sites except your nearest neighbor they all slow down from 1800 until 12pm the next day. Some are dramatic .. cyberhost is consistently slow and it gets a tatency bump as the same time as others.

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Commented:
David, can you explain about caching?  What's being cached?  And why is it happening at that particular time?  And what about the humps that show up on three of the five hosts?  Also, is this normal?  Or is something amiss?
These are indeed interesting and quite unusual graphs. Is it the same every day? Do you deploy and kind of traffic shaping device?

The increase in latency on the various graphs is not consistent with a similar increase in latency of "Frontier". Assuming Frontier is the first hop of your provider (at the other side of your access line), we can conclude that your access line only partially contributes in the periods of higher latency. The strange graph behavior must be somewhere else on route.

Perhaps you could use traceroute and look for latency bumps  on the route between you and the cloud providers. If you compare between periods of high and low latency, you might be able to identify where the problem is situated.

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