[ntp:questions] Detecting bufferbloat via ntp?

Dave Täht d at taht.net
Wed Feb 9 04:18:10 UTC 2011


Rick Jones <rick.jones2 at hp.com> writes:

> Dave T??ht <d at taht.net> wrote:
>> No, I am trying to come up with a reasonably passive way to detect
>> bufferbloat - which is only (currently) observable by doing latency
>> under load tests on the network edge - in the data center.
>
> So you are hoping that ntp's "natural" (albeit infrequent) latency
> measurements might expose it for you?

With a large enough dataset, the bufferbloat signature might stand out,
as it is often on the order of seconds, according to active measurement
tools such as netanalyzer. 

Not only that, but the originating timestamp data currently being
discarded might point to effective queue lengths measured in lunar
distances.

The noise that we've been filtering out may actually be at a dull roar. 

But I don't know. 

24 hours worth of rawstats data (if that contains enough information,
judging from the discussion on the list, it does) from a given ntp
pool or pools would be revealing.  

Would there be anyone here interested in collecting that data and poking
into this issue further? 


-- 
Dave Taht
http://nex-6.taht.net




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