Hi again, Did a little bit of reading and a simple test..
For software only PTP, you are probably better off with NTP. For hardware assisted PTP, only the NIC's have to support timestamping. Most Intel gigabit controllers do (IGP driver). I did run a couple of little tests in a pure virtual environment (pure software) and compared with NTP. I'm not overly pedantic, but NTP just feels better (in the fact it doesn't do horrid multicast stuff on my network). Sadly I do not have IEEE 1588 capable cards, so was unable to test in hardware assist. For a small network, NTP would probably suffice more. I tend to broadcast NTP servers through DHCP (easier to distribute) & run a central time server which all synch from. If you are wanting a feature-rich read on hardware assisted PTP.. http://www.linuxclustersinstitute.org/conferences/archive/2008/PDF/Ohly_92221.pdf Does however have a wealth of benefits over NTP mind, but looks to be more geared toward cluster computing. Ian On Tuesday 24 January 2012 18:53:03 Ian Grody wrote: > On Tuesday 24 January 2012 18:15:06 James Courtier-Dutton wrote: > > Hi, > > > > Does anyone have experience of both ntp and ptp ? > > Which is likely to be better (keep them synced to the best accuracy > > and lowest variance) at syncing three PCs on a LAN without a switch > > that supports ptp? > > My understanding is that in order for ptp to be better than ntp, the > > network switch has to also support ptp. > > Kind Regards > > > > James > > > > -- > > Please post to: Hampshire@mailman.lug.org.uk > > Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire > > LUG URL: http://www.hantslug.org.uk > > -------------------------------------------------------------- > > TBH I still use NTP. There is nothing I have that requires the high > precision of PTP. > > In essence, you only need multicast support since this is how it conveys > it's messages, but is also rumored to be runnable in unicast mode. > > If you require high precision time, PTP maybe a better option for you as it > has methods to account for network latency in conveying time messages. > > Give it a poke and see what works best for you :-) > > > Ian > > -- > Please post to: Hampshire@mailman.lug.org.uk > Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire > LUG URL: http://www.hantslug.org.uk > -------------------------------------------------------------- -- Please post to: Hampshire@mailman.lug.org.uk Web Interface: https://mailman.lug.org.uk/mailman/listinfo/hampshire LUG URL: http://www.hantslug.org.uk --------------------------------------------------------------
