From: Hobbs (deadheadblues@gmail.com)
Date: Mon Nov 03 2008 - 15:59:00 ARST
oh yeah. dont get me wrong. this is a test and you have get your points :) I
just used to have hard time with NTP and buckled down now i feel pretty
confident and can get it to work 99% of the time. In fact, whenever i get an
ntp task on a lab, im usually thinking "3 easy points"... :)
On Mon, Nov 3, 2008 at 10:14 AM, Scott M Vermillion <
scott_ccie_list@it-ag.com> wrote:
> Hey Hobbs,
>
> I guess my main point was that you don't want to stress over matters that
> are outside of your immediate influence - *especially* in the lab (and I'm
> specifically thinking backbone routers and their configuration here).
> Serious time can be lost chasing your tail. If you've properly configured
> NTP per your understanding of the task and the documentation, move on
> (IMHO). Obviously you'd come back to it later, time permitting. Never
> forget that the lab is a test of more than just technical prowess, right?
> It's mainly about that, but not exclusively. Again, IMHO.
>
> I'm a WAN guy with a background in SATCOM, T-Carrier, and SONET (etc). I
> have a pretty solid grasp of network timing and synchronization issues.
> This whole "Stratum 5" (and above) thing is a little humorous to me.
> Granted, the reasons for "synchronizing clocks" in an IP network are quite
> different than the reasons for doing so in the WAN domain. And I actually
> do understand the "logic" behind these nonexistent stratum levels. I just
> wish they could have found a better/less misleading syntax, personally
> speaking. But I guess there's rarely any value to being a purist, so it's
> not as though I'm losing any sleep over the matter. ;-)
>
> Regards,
>
> Scott
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Hobbs
> Sent: Sunday, November 02, 2008 6:01 PM
> To: Scott M Vermillion
> Cc: Huan Pham; CCIE Lab
> Subject: Re: NTP - Why NTP not synchronized, yet the router gets correct
> clock?
>
> I don't think checking the clock is proper way to view if routers are
> synced. You have to view the show ntp commands. On my online racks, the
> clock are always the current date and time. They have hardware clocks
> right?
> The only way to be sure if they are synced is if show ntp assoc/status
> shows
> they are. If the times are the same, it doesn't mean they have synced, or
> that one router got it from another.
>
> And if the task says they should be synced, then I would bet they are going
> to verify that with "show ntp stat/assoc" not "show run"...
>
> I give NTP a hard time but believe it or not, it is a simple protocol to
> use. You just have to be patient because sync/unsyncing can take a few
> packets and minutes. Its better to learn it than to chalk it up to being
> inherently buggy. If there's something that doesn't seem right, ask the
> group :)
>
>
> On Sat, Nov 1, 2008 at 6:35 PM, Scott M Vermillion <
> scott_ccie_list@it-ag.com> wrote:
>
> > Hi Huan,
> >
> > Apologize for the delayed response - I've been hammering away at GCOP
> > (Gutter Clean Out Protocol), LRP (Leaf Raking Protocol), and MMTSOOtFH
> > (Moving My Teenage Son Out Of the Freakin' House) lately.
> >
> > Sorry that didn't pan out for you. Bottom line is that it seems unlikely
> > that Cisco would somehow penalize you in the lab for something not
> > synchronizing properly if you've issued the appropriate commands, per
> their
> > documentation. I have my c877 edge router synched to an NTP server on
> the
> > Internet and all is well. But in preparing for the R&S lab, I found NTP
> to
> > be a tad flakey. I didn't stress over it too much, reasoning that this
> > would likely be a case where they would look for the presence of certain
> > commands vs. results. Obviously I have no idea whether that's truly the
> > case or not, but I would think the proctors are quite well aware of just
> > how
> > inconsistent this whole NTP affair can be.
> >
> > My thoughts anyway.
> >
> > Cheers,
> >
> > Scott
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > Huan
> > Pham
> > Sent: Friday, October 31, 2008 6:03 PM
> > To: 'CCIE Lab'; Scott M Vermillion
> > Subject: RE: NTP - Why NTP not synchronized, yet the router gets correct
> > clock?
> >
> > Hi Scott,
> >
> > Thanks for your suggestion. I tried it, but it gave different results
> each
> > time.
> >
> > I am not sure setting the Stratum to 1 does help here, or just the action
> > of
> > of removing and adding back the NTP peer that actually does help (in some
> > cases).
> >
> > By default, if you set NTP master without specifying the Stratum, it is
> set
> > to
> > 8. In the real lab context, we wont be able to set it freely (1 or 2 as
> you
> > suggested), but it has to be according to Lab requirement. For instance,
> if
> > the lab ask:
> >
> > Set R2 to get NTP clock from BB1 and R1 but BB1 should be the preffered
> one
> > (if availble). In this case, you wont be able to change the Stratum on
> BB1,
> > so
> > if it is set to 8 by default, then on R1 (as another Master), you have to
> > set
> > the Stratum to 8 or higher. Otherwise, R2 will always synch to R1 (lower
> > stratum), even if you put the prefered keyword on the peering to BB1.
> >
> > Cheers,
> >
> > Huan
> >
> >
> > --- On Fri, 10/31/08, Scott M Vermillion <scott_ccie_list@it-ag.com>
> > wrote:
> >
> > From: Scott M Vermillion <scott_ccie_list@it-ag.com>
> > Subject: RE: NTP - Why NTP not synchronized, yet the router gets correct
> > clock?
> > To: "'Huan Pham'" <pnhuan@yahoo.com>, "'CCIE Lab'" <
> ccielab@groupstudy.com
> > >
> > Date: Friday, October 31, 2008, 2:42 AM
> >
> > Hi Huan,
> >
> > I would suggest the following as a possibility:
> >
> > -Remove the 'ntp server 150.1.6.6' command from R5
> >
> > -Validate that the association is gone
> >
> > -Change R6 to 'ntp server 1'
> >
> > -Reapply the 'ntp server 150.1.6.6' command to R6
> >
> > Then give it a short time and post back as to whether or not you see a
> > "sane" and "synchronized" status.
> >
> > I have never tried setting the server to anything other than Stratum 1 or
> > 2.
> > In reality, there is no such thing as Stratum 5 (or above), so I'm not
> sure
> > that it's valid for a server to be configured for that level. Cisco
> takes
> > a
> > lot of liberties with the whole stratum thing, so it's hard to say one
> way
> > or the other. The command reference is silent on the matter and
> certainly
> > you can enter anything from 1 to 15. But for lab prep purposes I always
> > just went with 1 or 2 (obviously a Cisco router can't truly be Stratum
> 1!).
> > I just tried setting a server to 5 and met with the same results that you
> > did. Then I converted it to 1, but the other router still showed as
> > "insane," even after it reflected the new configured stratum level of
> > its
> > server. Only after I removed the config from the client and reapplied it
> > did I (almost instantly) get a "sane" status.
> >
> > Let us know...
> >
> > Scott
> >
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > Huan
> > Pham
> > Sent: Thursday, October 30, 2008 6:44 AM
> > To: CCIE Lab
> > Subject: NTP - Why NTP not synchronized, yet the router gets correct
> clock?
> >
> > Hi,
> >
> > This should be a very simple question, but NTP always bugs me.
> >
> > Scenario is simple. R6 is the NTP master, and R5 is client. It already
> > takes
> > ages, but I could not get R5 clock synchronized (status = unsynchronized,
> > insane). Yet, R5 picks up the correct clock from R6, even after I reload
> > the
> > router.
> >
> > You may ask to manually set clock of the two routers close to each other,
> > so the synchronization will speed up. I've done that and it does not
> help.
> > Anyway, client already picks up the clock (from the Server), so no need
> to
> > manually set it. The question is what can I do to get R5 to show status =
> > synchronized, and "sane".
> >
> > Any idea pls?
> >
> >
> > Rack1R6#sh run | in ntp
> > ntp source Loopback0
> > ntp master 5
> >
> >
> > Rack1R5#sh run | in ntp
> > ntp server 150.1.6.6
> >
> > Rack1R5#sh ntp associations detail
> > 150.1.6.6 configured, insane, invalid, stratum 5
> > ref ID 127.127.7.1, time CCB4C034.A6EF985D (23:22:28.652 UTC Thu Oct 30
> > 2008)
> > our mode client, peer mode server, our poll intvl 1024, peer poll intvl
> > 1024
> > root delay 0.00 msec, root disp 8354.68, reach 377, sync dist 8378.571
> > delay 47.67 msec, offset 154290.0900 msec, dispersion 0.06
> > precision 2**24, version 3
> > org time CCB4C049.1D3A1525 (23:22:49.114 UTC Thu Oct 30 2008)
> > rcv time CCB4BFAE.D9112EC7 (23:20:14.847 UTC Thu Oct 30 2008)
> > xmt time CCB4BFAE.CCD8B539 (23:20:14.800 UTC Thu Oct 30 2008)
> > filtdelay = 47.67 47.67 47.96 48.10 47.87 47.85 47.84
> > 47.93
> > filtoffset = 154290. 154290. 154290. 154290. 154290. 154290. 154290.
> > 154290.
> > filterror = 0.02 0.03 0.05 0.06 0.08 0.09 0.11
> > 0.12
> >
> > Rack1R5#sh ntp status
> > Clock is unsynchronized, stratum 16, no reference clock
> > nominal freq is 250.0000 Hz, actual freq is 250.0000 Hz, precision is
> 2**24
> > reference time is 00000000.00000000 (00:00:00.000 UTC Mon Jan 1 1900)
> > clock offset is 0.0000 msec, root delay is 0.00 msec
> > root dispersion is 0.00 msec, peer dispersion is 0.00 msec
> >
> >
> > (R5 after reload)
> >
> > Rack1R5#sh clock
> > *23:25:13.371 UTC Thu Oct 30 2008
> >
> > This is the same clock from R6.
> >
> >
> >
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