From: ccie2be (ccie2be@nyc.rr.com)
Date: Thu Jun 26 2003 - 15:54:15 GMT-3
Hey Jay,
Thanks for your reply.
A quick little config change on rtr-2 has proved your suggestion correct.
I'm going to play around with this some more to see how much the difference
in stratum needs to be for multiple ntp masters to sync up properly, but
thanks for sharing your thoughts with me. It did the trick.
BTW, in terms of NTP, to count the "hops", I would count the number of NTP
servers daisy chained to one another? For example, given rtrs A, B, C, D,
and E where E is configured to get ntp from C and C is configured to get ntp
from A and A is the master, router E considers rtr A to be 2 hops aways?
(Rtrs B and D just provide connectivity and aren't ntp servers). Do have it
right?
Thanks again.
----- Original Message -----
From: "Jay Hennigan" <jay@west.net>
To: "ccie2be" <ccie2be@nyc.rr.com>
Cc: "Group Study" <ccielab@groupstudy.com>
Sent: Thursday, June 26, 2003 2:10 PM
Subject: Re: NTP
> On Thu, 26 Jun 2003, ccie2be wrote:
>
> > I have 2 2500's connected via ethernet and they can ping each other's
loopback
> > and ethernet addresses.
> >
> > This is the NTP config of each:
> >
> > RTR-1
> >
> > ntp master 6
> > ntp server 192.168.2.2 source lo0
> >
> >
> > RTR-2
> >
> > ntp master 7
> > ntp server 192.168.1.1 source lo0
> >
> >
> > Both routers have there system clocks set to different dates and times.
> >
> > When I do a "show ntp asso det" on rtr-2, it shows
> >
> > 192.168.1.1 configured, insane, invalid...
> >
> > Why is this and what should I do about it?
>
> I haven't tested this in the lab, but a thought...
>
> Each "hop" increases the stratum by one. If r2 is a master at stratum
> 7 and r1 has a widely varying time and reports itself as stratum 6, then
> r2 has two sources that are effectively stratum 7. As it is itself a
> master, it will reject the data from the peer at the same stratum as
> "insane" if the time is different.
>
> What is the behavior if the strata differ by 2 or more? Change r1 to
> master at stratum 5 for example.
>
>
> --
> Jay Hennigan - CCIE #7880 - Network Administration - jay@west.net
> WestNet: Connecting you to the planet. 805 884-6323 WB6RDV
> NetLojix Communications, Inc. - http://www.netlojix.com/
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