[ntp:questions] Re: What can be uses as an SNTP server

Richard B. Gilbert rgilbert88 at comcast.net
Sun Jun 12 14:54:29 UTC 2005

David Woolley wrote:

>In article <ywn9d5qs9vil.fsf at ntp1.isc.org>,
>Harlan Stenn <stenn at ntp.isc.org> wrote:
>>I just re-read the draft 2030 spec and it says that the legal values for
>RFC 2030 is released.  It can't be a draft.  Any replacement will have
>a new RFC number.  It will either obsolete RFC 2030 or define a new version
>of the protocol.  (For example, the NTP v4 RFC, when it arrives, will not
>obsolete RFC 1305.)
> <snip>
>You may be proposing a new RFC.  In that case, I doubt that you can change
>a SHOULD NOT into a MUST NOT without creating a new version of the protocol,
>as I very much doubt that IETF likes retrospective legislation.  To get
>your desired effect in a new version of the protocol, you would need to 
>have something like:
>   1        primary reference (this value SHALL only be used by
>            <definition that doesn't depend on the use of "e.g.">)
>   2-15     secondary reference (these values SHALL only be used by
>            a server fully implementing NTP (RFCxxxx))
That seems to me to be entirely too many strata!   Since each stratum 
degrades the quality of time; sometimes significantly, stratum 14 would 
likely be no better than your great grandfather's tall case clock 
(commonly called a grandfather clock).

Stratum ten is "conventional" for an unsynchronized local clock because 
nobody is likely to listen to or believe a server claiming stratum ten 
if there is any other choice.

Is anybody synchronizing anything to a stratum higher than five or six?  
(other than servers running unsynchronized local clocks?)

I've read elsewhere that stratum is an eight bit field.  It seems to me 
that five of those bits might be dedicated to some more useful purpose; 
e.g. indicating a sever using SNTP, a server using an unsynchronized 
local clock, a secondary server with fewer than four upstream sources, etc.

Some of the bits might be used to indicate the type of reference clock 
since some are much more desirable than others; e.g. a server 
synchronized to GPS at stratum 1 is more desirable than a server 
synchronized to an HF radio clock at stratum one.

More information about the questions mailing list