From: Sean C (Upp_and_Upp@hotmail.com)
Date: Wed Jan 05 2005 - 15:57:32 GMT-3
Hi Chuck,
Good to write to you again - has been awhile.
I should have mentioned - I tried NTP master at spots - even incremented
them the farther I away I went from the GPS - but no go.
For example, tried
3600 - NTP master 4
2600#1 - NTP master 5
2600#2 - NTP master 6
etc...
but still couldn't the leaf routers to synch up. Oh yes, they would get the
time, but not be synched.
Again thanks, Sean
----- Original Message -----
From: "Church, Chuck" <cchurch@netcogov.com>
To: "Sean C" <Upp_and_Upp@hotmail.com>; <ccielab@groupstudy.com>
Sent: Wednesday, January 05, 2005 1:38 PM
Subject: RE: Real NTP scenario
I don't believe any router will PROVIDE NTP until it's configured with
'ntp master (stratum number)'. At least that's my understanding of it.
Chuck Church
Lead Design Engineer
CCIE #8776, MCNE, MCSE
Netco Government Services - Design & Implementation Team
1210 N. Parker Rd.
Greenville, SC 29609
Home office: 864-335-9473
Cell: 703-819-3495
cchurch@netcogov.com
PGP key: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x4371A48D
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Sean C
Sent: Wednesday, January 05, 2005 11:40 AM
To: ccielab@groupstudy.com
Subject: OT: Real NTP scenario
Hello,
I can get NTP going in a lab enviroment. But, I'm having trouble with a
real
case. Is it possible to link multiple routers together with NTP - each
cascading off the router before it? Whenever I try it, routers
downstream can
see the router above them and see some of the NTP info, but they don't
synch
up. I've tried using different configs - NTP server on different
routers, NTP
source-interface and NTP peering instead of NTP server - no good. I'm
wondering if there is some 'max-hops' one can be from a NTP device that
is
defined as a server. I've looked through the RFC but still lost. Any
help
would be appreciated.
Sorry for the long output.
Here's an example:
GPS NTP server (Available thru the web)
|
|(Internet)
|
3600 router
|
|(FR PVCs to 2600router#1)
|
2600 router#1
|
|(FR PVC to 2600router#2)
|
2600 router#2
****************************************
Here's the config from the 3600 to the GPS server. The clock and ntp
association both look good.
3600router#sh clock
10:13:04.123 EST Wed Jan 5 2005
3600router#srb ^ntp
ntp clock-period 17208278
ntp server 128.249.1.1
ntp server 131.144.4.9
3600router#sh ntp ass
address ref clock st when poll reach delay offset
disp
~128.249.1.1 128.42.59.172 3 29 64 377 29.4 -801.3
238.1
*~131.144.4.9 .GPS . 1 29 64 377 22.2 -809.4
201.4
* master (synced), # master (unsynced), + selected, - candidate, ~
configured
3600router#sh ntp status
Clock is synchronized, stratum 2, reference is 131.144.4.9
nominal freq is 250.0000 Hz, actual freq is 249.5872 Hz, precision is
2**16
reference time is C5868163.572891CD (10:08:19.340 EST Wed Jan 5 2005)
clock offset is -809.4360 msec, root delay is 22.16 msec
root dispersion is 1013.79 msec, peer dispersion is 201.37 msec
**********************************************************************
Here's the output from the 2600#1 that is off of the 3600. I have it
pointed
to the 3600's directly connected Serial IP:
2600router#srb ^ntp
ntp clock-period 17179680
ntp server <3600 Serial IP>
end
2600router#sh clock
10:12:39.170 EST Wed Jan 5 2005
2600router#sh ntp ass
address ref clock st when poll reach delay offset
disp
~<3600 Serial IP> 131.144.4.9 2 31 64 17 91.9 311.44
1980.0
* master (synced), # master (unsynced), + selected, - candidate, ~
configured
2600router#sh ntp status
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 250.0027 Hz, precision is
2**19
reference time is C58680F5.B82EDC8A (10:06:29.719 EST Wed Jan 5 2005)
clock offset is -791.5767 msec, root delay is 117.87 msec
root dispersion is 2345.78 msec, peer dispersion is 16000.00 msec
**********************************************************************
If I now try to have some other routers use the 2600#1 as their NTP
server,
the routers will never synch up. I've tried with NTP on 2600s and even
SNTP
on 1700s - no good. I assume it's because the 2600#1 isn't synched to
the
3600:
2600router2# sh ntp ass
address ref clock st when poll reach delay offset
disp
~<2600#1serial IP> 0.0.0.0 16 32 64 0 0.0 0.00
16000.
* master (synced), # master (unsynced), + selected, - candidate, ~
configured
2600router2#sh ntp stat
Clock is unsynchronized, stratum 16, no reference clock
nominal freq is 250.0000 Hz, actual freq is 249.9964 Hz, precision is
2**19
reference time is C5869074.CC5470D5 (11:12:36.798 EST Wed Jan 5 2005)
clock offset is -736.5485 msec, root delay is 147.55 msec
root dispersion is 5949.17 msec, peer dispersion is 16000.00 msec
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