North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Non-GPS derived timing sources (was Re: NTp sources that workin a datacenter)
On Mon, 2 Jun 2003, Leo Bicknell wrote: > Could it be that providers actually have multiple sources, but for > some reason GPS is always picked as the primary source for the > public facing function? At least a few providers keep their actual > sources (the receivers themselves) "hidden", and provide a unix box > syncing to all of them as the front end. From my limited knowledge, > that front end box will only show the one source it has picked as > "best". Like all answers, it depends. A relatively small number of providers have blocked access to their "master" NTP servers. So you can't see the current source from the next stratum down. You get a domain name, like ntp-1.ispdom.ain, for the source. But a large number permit queries to their NTP servers. They will report all the stratum 0 sources available, including the current sync'd source. Almost no providers use more than one stratum 0 source per NTP server. The people with lots of stratum 0 sources are almost never network service providers. Generally NSPs have 1 stratum 0 source, a two or three stratum 1 peers, and lots of stratum 2s. Most providers don't have a dedicated NTP infrastructure, so their tickers are running on routers and general purpose servers. Due to the way NTP works, it is a self-directed hierarchy. A stratum 1 chimer is only at the top while its synced to a stratum 0 source.
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