From: Nick Shah (nshah@xxxxxxxxxxxxxx)
Date: Wed Aug 28 2002 - 01:31:24 GMT-3
Dmitry
The first & foremost requirement is that atleast one peer must be
operating in symetric active, client or broadcast mode.
If both peers are acting in passive mode, they will both ignore each other;s
messages.
By being synchd with 'itself' what I mean is that, in the absence of a lower
stratum clock, the NTP server will chose to consider 'itself' reliable and
synch with itself. Within the time it is not synchronised (do show ntp stat)
no one else will synch to it.
rgds
Nick
----- Original Message -----
From: "Volkov, Dmitry (Toronto - BCE)" <dmitry_volkov@ca.ml.com>
To: "'Nick Shah'" <nshah@connect.com.au>; <Dan.Thorson@seagate.com>; "'Brian
Dennis'" <brian@5g.net>
Cc: <ccielab@groupstudy.com>
Sent: Wednesday, August 28, 2002 1:13 PM
Subject: RE: NTP server/peer
> Nick, Brian, Dan,
>
> Still - not clear.
>
> > -----Original Message-----
> > From: Nick Shah [mailto:nshah@connect.com.au]
> > Sent: Tuesday, August 27, 2002 10:02 PM
> >
> > How/Where can you use it ? Well, in a distribution layer you
> > could have
> > 'peers' who can synchronise with each other, when a server is
> > unreachable.
>
> 3 scenarios:
>
> 1) Two boxes without lower stratum clock source:
>
> R1---------R2 on R1: ntp peer (ip add of r2) on R2: ntp peer (ip add of
r1)
> They don't sync each other - their stratum 16 (and even don't try - i
> checked via debug)
> The same situation using "ntp server" pointing to each other. If no clock
> source (stratum lower than 16) - No sync.
>
> 2)
> If I have one box synchronized with lower stratum, I can setup other box
to
> get time from first box using "ntp peer" or "ntp server" - I don't see
> difference ...
>
> 3) If I have two lower stratum clock sources with IP a.a.a.a and IP
b.b.b.b
> I configure two boxes:
> 3.I) with "ntp server a.a.a.a prefer" and "ntp server b.b.b.b"
> 3.II) with "ntp server b.b.b.b prefer" and "ntp server a.a.a.a"
>
> Why Dan did use "ntp peer" in this case ?
>
> > Remember a Server would be at a lower stratum number hence
> > more preferable,
> > in absence of which, the Peers can choose to synchronise with
> > either/each
> > other.
> > And last but not least, the most important rule, no client/peer will
> > synchronise with the Server/Peer if that server/peer is in turn not
> > not synchronised with itself.
>
> What does it mean - "not synchronised with itself" ? How it can be sych
with
> itself ?
> I guess using "ntp master" only ?
>
> Thanks,
>
> Dmitry
>
> > rgds
> > Nick
> >
> > ----- Original Message -----
> > From: "Volkov, Dmitry (Toronto - BCE)" <dmitry_volkov@ca.ml.com>
> > To: <ccielab@groupstudy.com>
> > Sent: Wednesday, August 28, 2002 7:31 AM
> > Subject: NTP server/peer
> >
> >
> > > Hello,
> > >
> > > Can somebody explain the difference between "ntp server"
> > and "ntp peer"
> > > commands ?
> > >
> > > I always used to use "ntp server".
> > >
> > > I read this:
> > >
> > http://www.cisco.com/univercd/cc/td/doc/product/software/ios12
> 1/121cgcr/fun_
> > c/fcprt3/fcd303.htm#xtocid2708216
> > and Doyle and Solie... and still don't understand when is suitable to
use
> > "ntp peer".
> >
> >
> > Thanks,
> >
> > Dmitry
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