[mat-wg] New on RIPE Labs: Further Virtualisation Testing for RIPE Atlas Anchor

Hi Randy,

On 13/09/16 01:59 , Randy Bush wrote:
>> https://labs.ripe.net/Members/romeo_zwart/LuigiCorselloAtlasanchorvirtualisationfinalreport.pdf
> 
> nice masters level work, which i presume it was.  of course, the devil
> is in the details, and he seemed to be dealing with a lot of devils.

Thanks for taking the time to review. I will forward your comments, I am
sure the researcher will be pleased with your constructive criticism.

[...]

> i was worried by
> 
>     In fact, the first TTM node for time monitoring (tt97.ripe.net)
>     resided in a different VLAN than the POC and had an average delay
>     of about 1100μsec! That was certainly not good enough to measure
>     sub millisecond time accuracy and was replaced by tt999.ripe.net
>     installed in the same VLAN as the POC.
> 
> ntp is designed to be pretty insensitive to rtt.  so this either scares
> the hell outta me about ttm, is a misunderstanding, or miscommunication.
> i would love to see more analysis of this.

This is a misunderstanding and probably only reflects a very early view
of the researcher on the topic. I don't believe it was intended to
comment on the quality of the TTM mechanism. :)

WRT you other question about more work along these lines on TTM. I think
it's unlikely we will follow this up further. The researcher has moved
on the greener fields in the mean time and a lot of work on TTM has been
done in the early 2000's and before, see e.g. [1]. Although that
particular reference is not specifically looking TTM accuracy.

> side note: it would have been nice if he had run openvz and kvm on
> something less paleolithic than centos.
>
> but my compliments to the researcher and to the ncc for funding him.
> useful work.

Thanks for that comment. I will pass it on. :)

> randy
> 

[1] http://www-nas.et.tudelft.nl/people/Piet/papers/PAM2002.pdf