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From: Terje Mathisen "terje.mathisen at on 23 Jan 2010 13:19
Morten Reistad wrote:
> In article<7a7r27-mu21.ln1(a)ntp.tmsw.no>,
> Terje Mathisen<"terje.mathisen at tmsw.no"> wrote:
>>> *172.79-161-68.c .GRMN. 1 u 38 64 377 8.548 -9.575 8.038
>>
>> Hmmm. That's pretty bad, actually. I hope this was taken shortly after
>> first sync? After a few hours you should see significantly lower jitter
>> and offset values!
>
> Yep.
>
[snip]
> I am on a cable network, "GET", with lots of bandwidth, but it is through
> tons of weird repeaters and has a 10k host flat ethernet (i can see the
> arp's; around 300 kb/s sustained traffic) so it is full of jitter.
> Currently 6mb up, 16 down. I cannot detect latency differences up and down
> through the jitter.
>
> I therefore got a second opinion :
>
> From faxe, located inland from Copenhagen. Excellent network, I have
> uncapped 100mb/s bandwith. Copenhagen is a nice compromise between
> local to Scandinavia, and well reachable to the rest of the world.
>
> remote refid st t when poll reach delay offset jitter
> ==============================================================================
> +mail.tyroll.dk gps.dix.dk 2 u 22 256 377 0.588 3.932 0.404
> -host3.typomedia www.movieget.co 3 u 21 256 377 0.853 5.958 0.416
> +blah.jabber.dk gps.dix.dk 2 u 24 256 377 0.983 4.573 0.069
> -4504ds1-vo.2.fu ntp.ngdc.net 3 u 5 256 377 26.315 9.081 0.651
> *172.79-161-68.c .GRMN. 1 u 67 256 377 10.607 4.408 0.257

Sub-ms jitter with 256-second polling is much more like it. :-)
>
>
> I keep watching the ntp reports.
>
> In PPOEs I discovered that watching NTP closely tended to give advance
> warning about hardware failures. It told us clearly about temperature
> anomalies. I made a little morning report for me, the technical manager;
> taking that report above; adding the source machine as a column; sorting
> the host-host pairs by jitter; assigning a rank and reporting everything
> that changed rank by more than 25 places since yesterday.
>
> I also reported machines that went in and out of favour with large amounts
> of other machines. If 10 routers are synced to box x today, but there were
> 50 yesterday, then something happened, enough to log onto box x to have a look.

_Very_ nice idea, I'll see if I can use it!
>
> By gut feeling is that the firewall here is about to fail.

Or GET is just as bad as they used to be while called UPC?

Broadband providers who feel they have to change their name and re-brand
completely is a bad sign. :-(

Terje

--
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"
From: Morten Reistad on 23 Jan 2010 16:09
In article <m6rr27-kp31.ln1(a)ntp.tmsw.no>,
Terje Mathisen <"terje.mathisen at tmsw.no"> wrote:
>Morten Reistad wrote:
>> In article<7a7r27-mu21.ln1(a)ntp.tmsw.no>,
>> Terje Mathisen<"terje.mathisen at tmsw.no"> wrote:
>>>> *172.79-161-68.c .GRMN. 1 u 38 64 377 8.548 -9.575 8.038
>>>
>>> Hmmm. That's pretty bad, actually. I hope this was taken shortly after
>>> first sync? After a few hours you should see significantly lower jitter
>>> and offset values!
>[snip]
[snap]
>> I am on a cable network, "GET", with lots of bandwidth, but it is through
>> tons of weird repeaters and has a 10k host flat ethernet (i can see the
>> arp's; around 300 kb/s sustained traffic) so it is full of jitter.
>> Currently 6mb up, 16 down. I cannot detect latency differences up and down
>> through the jitter.
[snip]
>Sub-ms jitter with 256-second polling is much more like it. :-)

>> By gut feeling is that the firewall here is about to fail.
>
>Or GET is just as bad as they used to be while called UPC?
>
>Broadband providers who feel they have to change their name and re-brand
>completely is a bad sign. :-(

Janco, then UPC, then Chello, now GET. All name changes because the old
name was too tainted.

GET is getting better. Downtime is now a few hours per year. It used
to be a week or two. Now the equipment has backups for important lines
and power feeds.

But they are slowly joining the fiber provider in mentality. These
are all unable to work above layer 2 in the osi model. Everything
done as ethernets. Large ethernets, concentrated over fiber to some
very few, but huge switches and routers.

-- mrr



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