The poster is asking about ethernet over power line and not power over ethernet. As you point out, the later should have zero effect on ethernet latency.
There are several ethernet over power standards. Latency will include a bridge in each adapter, the effects of a noisy uncontrolled AC power line when ARQ (automatic repeat query) is used, and the TDMA or CSMA media access control system. I suspect varying power line conditions will have the largest effect because any jitter from the media access control system will be multiplied by ARQ. On Sun, 10 Feb 2013 08:14:38 -0800, Chris Albertson <albertson.ch...@gmail.com> wrote: >THose power over Ethernet devices work with analog signals and don't >evn look at the data packets. All they do is place a DC bias on the >twisted pair. Ethernet is always transformer coupled so your >routers, switches and computers never see DC. > >What is your NTP server using for a reference clock? I'd suspect that >is the problem. If the reference is an Internet pool server than a >few mS is about what you should expect. If using GPS then look to >see if you have a good signal from enough satellites. > >But those POE boxes don't mess with the data packets, or at least the >are not designed to do that. If one is broken it could be adding >noise to the line. Broken hardware can do "anything". > > > >On Sun, Feb 10, 2013 at 3:18 AM, Rob Kimberley ><robkimber...@btinternet.com> wrote: >> I'm not sure if this is the best place to ask the question, but does anyone >> have experience of using Ethernet over power line adapters? I have an >> outside office, and my router is in the house plugged into the phone master >> socket. I have used two Ethernet over power adapters, one at the router and >> one in the office here to get internet access. The output of the adapter >> then goes to a multi-port hub to give me Ethernet to all my office devices >> including two Meinberg NTP servers. >> >> I've noticed large jitter readings on Meinberg's NTP monitor program. Can >> be as low as 2ms, but much higher (50mS +), and at this point NTP goes >> haywire. >> >> Not sure if it is the physical set up or something else. >> >> Any comments appreciated. >> >> Thanks. >> >> Rob _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.