CMM as NTP server

It would seem to me reasonable to expect a CMM to be an NTP server.

but at the same time, the pre-existing NTP servers I have deployed are going a great job.

Sure, your idea would save alittle bit of traffic on the uplink though.

ahull wrote:
but at the same time, the pre-existing NTP servers I have deployed are going a great job.

Sure, your idea would save alittle bit of traffic on the uplink though.

Anyone can deploy an NTP server... I have set them up often. I am not interested in saving the trivial few bytes of bandwidth I would save by not participating in the NTP network.

Unless you are running a seperate time standard rather than just pulling time across the network from one of the "Time Lords", you are most certainly not going to be as accurate as GPS time would be.

My NTP servers are accurate and reliable enough as well, but wouldn't it be nice to have the GPS clock used to provide NTP for your local network? In view of the fact that AP's can be set up to get their time from an NTP server, it would seem quite reasonable to expect the Canopy system to include an NTP server. Since the system is based upon BSD anyway, it would seem trivial to include a time daemon.

The CMM is the logical place to put it.

It does make sence that using the time provided by the GPS would be pretty cool. Could even add my CMMs in as a time source in the NTP servers.

Interesting perspective, thanks.

What are you guys using for your NTP servers? I’ve never set one up - done a lot with routers and firewalls, web and ftp servers, speed test servers a little with BSD.


The CMM Micro already is an NTP server.

PatrickR wrote:
The CMM Micro already is an NTP server.

Yes, but HOW does the CMMmicro get the correct time? I've seen no place to input the time and date or an IP address to another NTP server. I was told over and over again during Canopy training that the GPS and the CMMmicro do NOT provide date and time. Can someone clarify this?
The CMM Micro already is an NTP server

That isn't true. The CMM distributes timing pulses and date/time information derived from the GPS receiver to the Canopy Access Points - the date and time only show up on the GPS page. It does not serve as a Network Time Protocol server.


So then what exactly does the NTP Server IP Address parameter in the Time & Date section of the AP’s and BHM’s get?

On my CMM Micro POPs I enter the IP address of the CMM Micro into this config and it pulls the time derived from the GPS and propogates it to the AP’s and BHM’s.

Are you guys saying that it would be a true NTP Server only if it did the conversion to your local time instead of GMT?

First, apologies for cross-posting. But I think everyone that’s posted here should be informed about how this stuff works:

GPS works on basis of transmitting the current time from multiple orbiting satellites. A position on ground will receive those signals slightly off-time from each other, and now you can calculate your position based on orbits and time skew. A side effect is you also know the current time, which you can then +/- your time zone to have local time. Nifty eh?

My CMM with the newer firmware does have an NTP, and it does answer requests. However my NTPd do not like to use it as a time source for some reason. I’ve recently read elsewhere that the CMM’s NTP rounds time to the nearest second, and so the network perceives a high jitter from the NTP’s responses. Found a post to the ISC mailing list via Google: