[ntp:questions] NTP over redundant peer links, undetected loops

Terje Mathisen "terje.mathisen at tmsw.no" at ntp.org
Wed Feb 11 20:35:07 UTC 2009


Stefan Schimanski wrote:
> Hi!
> 
> We are trying to implement a NTP installation over a redundant
> network, connecting the stratum 2 servers to the stratum 3 clients.
> The precise situation is the following (compare with
> http://1stein.org/download/network.png):
> 
> 3 networks, 192.168.3.0, 192.168.4.0, 192.168.5.0
> ATOM1, ATOM2 - stratum 1 servers in network 3
> GW1, GW2 - stratum 2 servers in all networks, i.e. 3, 4, 5
> CLIENT1...CLIENTn - stratum 3 clients in network 4 and 5

I did quite a bit of work while setting up a big corporate network, with 
dual servers, one of which had a Motorola Oncore UT+, in each of three 
geographically distributed locations.

I had similar plans like you, wanting to setup two or three layers of 
servers, but then I realized that this was totally superfluous!

We had less than 40K server and client machines worldwide, so even if 
every single one of them configured all 6 primary servers, the resulting 
load would be negligible, the timing results would be optimal, and so 
would the redundancy level.

The icing on the cake is that I don't need to consider where a client 
machine is located, I simply tell everyone to use exactly the same 
configuration file, with one exception:

The core/root DNS servers (as well as DHCP servers and some other 
network gear) use the same six servers, but they use the IP addresses 
directly instead of the DNS names.

Terje
-- 
- <Terje.Mathisen at tmsw.no>
"almost all programming can be viewed as an exercise in caching"




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