[ntp:questions] Re: Router Vendor + NTP

roy roy at suespammers.org
Sun Jun 12 13:52:05 UTC 2005

David Carne wrote:
> C.P.T.N members,
> I work for a small router vendor, and we're just about to release our
> first product. We plan to use NTP to synchronize the times on our
> devices, but we want to be good netizens, and run our own ntp
> infrastructure for our devices.

This sounds very good!  I'm glad to see a vendor in this market segment
taking the ethically high ground in this area.

> Does anyone have any advice on this? AKA, expectations of what we'll
> need in terms of bandwidth / what kind of server hardware we'll need?
> We expect to have eventually 100k+ devices out there, and the devices
> will probably synchronize one a week or so. [we have no need of really
> really accurate timekeeping].

You have no need for accurate timekeeping?  What about your customers!
They probably don't need to examine the router event logs on a regular
basis.  But when I do that, I find that event logs become difficult to
correlate when the time logged is not accurate.

But I admit that I am probably an atypical router consumer.  Not only
do I review router event logs, but I also update the router firmware.

> So in summary, do you all think I can do this with a single powerful
> box? or should I do something with round robin dns load balancing?

The processor and memory requirements for an NTP server are minimal by
today's standards.  Network bandwidth requirements can be more
significant.  For example, a company I work with uses a good quality,
commercial NTP server appliance.  It has a 133 MHz processor and
100Base-T Ethernet connection.

In my opinion, multiple servers in geographically dispersed data
centers is the way to go.  Your router SNTP software should be
configurable with multiple timeserver DNS names / IP addresses and
should automatically switch if the server stops responding or the
response time gets too high.  This saves your company in support costs,
because failures (extended power failure, network outage, hardware
failure, etc.) do not take down your time services network.  Take a
look at how geographically dispersed the NIST timeservers are.

> Apologies for the intrusion, but after reading all the discussion about
> how some router vendors abuse the system, we want to make sure we do
> things the right way.

No apologies needed.  Thank you for asking.


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