Interesting. Maybe a clock drift on the ONT. With longer differential you'd be more sensitive to it.
________________________________ From: AF <[email protected]> on behalf of dbernardi <[email protected]> Sent: Wednesday, August 20, 2025 2:35 PM To: [email protected] <[email protected]> Subject: Re: [AFMUG] how is underground FTTH done? DZS does as well and can even do it automatically and keep the laser shut down until ONT is booted but fears of that going sideways keeps that option from being used, but OPS likes to dispatch techs. The rogue ONU thing seems to happen more often (no concrete data to provide) on PONs with greater ONU differential than those in a tighter cluster which is why I brought it up. On 8/20/2025 2:10 PM, Adam Moffett wrote: > We're in tangent land now, but Nokia has a command you can send to the > ONT to stop transmitting for a specified period of time. So in theory > you can find that rogue ONT by ordering each one to shut down for a > minute and see which one makes the problem go away. > > I say "in theory" because the command is in the manual, but when I enter > it on the CLI it tells me it's not available yet. I wonder if they have > it working in Altiplano. > > -Adam > > > ------------------------------------------------------------------------ > *From:* AF <[email protected]> on behalf of dbernardi > <[email protected]> > *Sent:* Wednesday, August 20, 2025 1:57 PM > *To:* [email protected] <[email protected]> > *Subject:* Re: [AFMUG] how is underground FTTH done? > > > Not for some Dasan/DZS OLTs. You have to define both max distance and > max differential if exceeding 20km. If you have a single 1:32 splitter > 25km from the OLT on a PON port with even a handful of ONTs within close > distance of each other you will have issues. > > Optical budget and timing are related but pretty much independent. The > OLT tells each ONU when to transmit (similar to DOCSIS) so timing is > important. > > We've also seen 'rogue' ONUs caused by timing issues because their > transmission interferes with other ONUs signals. This is typically > observed as LOSi or SFi Alarms (but not for the offending unit), and in > some cases requires divide and conquer at the splitter ports to find the > offending unit. > > > On 8/20/2025 11:07 AM, Adam Moffett wrote: > > I think it's always been a differential distance, not a maximum > > distance. I think a lot of people just misinterpret it. > > > > ------------------------------------------------------------------------ > > *From:* AF <[email protected]> on behalf of Chuck <chuck@go- > mtc.com> > > *Sent:* Tuesday, August 19, 2025 4:55 PM > > *To:* [email protected] <[email protected]> > > *Cc:* [email protected] <[email protected]> > > *Subject:* Re: [AFMUG] how is underground FTTH done? > > There was in the beginning due to the timing and cuing of ONT upstream. > > It was to ensure 32 ONTs could all be transmitting max traffic at the > > same time. That is what Calix told me many years ago. > > Sent from my iPhone > > > > On Aug 19, 2025, at 11:50 AM, Josh Luthman > > <[email protected]> wrote: > > > > > > From what I've read, the issue was the timing between the farthest > > & closest ONT. There was no 20km timing limitation from OLT to > > anything. > > > > On Tue, Aug 19, 2025 at 12:39 PM <[email protected] <mailto:chuck@go- > > mtc.com>> wrote: > > > > Original GPON specs had a timing limitation of 20 km. > > > > *From:* AF <[email protected] <mailto:af- > > [email protected]>> *On Behalf Of *Josh Luthman > > *Sent:* Tuesday, August 19, 2025 6:31 AM > > *To:* AnimalFarm Microwave Users Group <[email protected] > > <mailto:[email protected] <mailto:[email protected]>>> > > *Subject:* Re: [AFMUG] how is underground FTTH done? > > > > Class C optics are rated for 60km or 42mi. That's a hell of a > > distance when you're only doing 1:32. We did 1:2 and 1:32 on > > the sixteenth PON port until we built more to justify another > OLT. > > > > On Mon, Aug 18, 2025 at 6:13 PM Chuck McCown <[email protected] > > <mailto:[email protected] <mailto:[email protected]>>> wrote: > > > > When you work out a 32:1 GPON, the timing distance > > limitations are exhausted before you run out of light. > > Splits are a 3 dB loss. A good splice will be .02dB. So > > don’t worry about splices. > > > > *From:* AF [mailto:[email protected] <mailto:af- > > [email protected]>] *On Behalf Of *Dev > > *Sent:* Monday, August 18, 2025 9:56 AM > > *To:* AnimalFarm Microwave Users Group <[email protected] > > <mailto:[email protected] <mailto:[email protected]>>> > > *Subject:* Re: [AFMUG] how is underground FTTH done? > > > > The thing with PON is that every time the light hits a > > splitter it loses a bit of strength, so you sort of have to > > plan to use a little hotter SFP in your OLT sometimes. > > Luckily, those are getting way cheaper nowadays, so it’s not > > the end of the world, but you do have to plan for that. > > > > Plus, each splice you do cuts down the signal a bit more. > > Fusion splicers only lose a tiny bit, but a physical > > connector can lose a bunch more, like the equivalent of a > > mile or more of distance, and a piece of crud on an > > uncleaned connector can lose 5 miles distance, so make sure > > you clean them with those cheap cleaner tools. > > > > On Aug 18, 2025, at 8:39 AM, Josh Luthman > > <[email protected] > > <mailto:[email protected] > <mailto:[email protected]>>> wrote: > > > > Splitters are waaay small. Smaller than a standard > > house key. > > > > What you are looking at is an MST terminal, looks like 8 > > ports. There can be a splitter inside of that yes. You > > can have the MST with 8 fibers splice to another 8 > > fibers or you can have what is in your picture have 1 > > fiber in, split 1x8, and then have 8 ports out for the > > installers to simply plug in to. > > > > If that MST is a 1x8, you can have a 1x4 before it, > > between the MST and OLT. That makes for OLT -> 1x4 > > splitter -> 1x8 splitter/MST. That is still a 1x32 > split. > > > > On Mon, Aug 18, 2025 at 11:34 AM Ken Hohhof > > <[email protected] <mailto:[email protected] > <mailto:[email protected]>>> wrote: > > > > I thought PON used like 16:1 or 32:1 splitters, and > > in this photo, I assumed that’s what the black boxes > > were. > > > > *From:* AF <[email protected] <mailto:af- > > [email protected]>> *On Behalf Of *Josh Luthman > > *Sent:* Monday, August 18, 2025 10:16 AM > > *To:* AnimalFarm Microwave Users Group > > <[email protected] <mailto:[email protected] > <mailto:[email protected]>>> > > *Subject:* Re: [AFMUG] how is underground FTTH done? > > > > Don't assume that about aerial. That's not how it > > works. Don't think about it in terms of taps. > > > > Generally speaking, installations are PON. What we > > do is design the fiber so we can hook up 100% of > > homes. We assign a color to every house. > > > > The first thing to think about is that you have to > > access the individual strand out of the cable, be it > > 12/24/48/144/etc. That is done with a SpliceCase or > > you splice on an MST for an ez mode plug. At > > Imagine we only splice - no connectors, no MST, no > > plugs, etc. > > > > > > Second thing is that when there's a cable up and > > down the road, you just need access to it through > > the case/MST from the house. This can be from the > > house to the handhole (concrete box in the ground) > > or you can run it from the house to the handhole > > through some 1.25" duct to the next handhole where > > there is one case. > > > > I can show you what it looks like if you don't get > > it yet. > > > > On Mon, Aug 18, 2025 at 11:11 AM Ken Hohhof > > <[email protected] <mailto:[email protected] > <mailto:[email protected]>>> wrote: > > > > The fiber train left without me, so maybe > > someone here can help me understand how the > > physical installation is typically done. > > > > I’ve seen aerial fiber and it’s pretty > > straightforward, I see splitters up on poles > > maybe at each intersection, and to hook up a > > customer, they run a drop wire from the nearest > > splitter to the house. If take rate is better > > than expected or a new house is built, worst > > case I assume they just add a splitter. > > > > But I also see FTTH deployments going in where > > they are boring for duct in the ROW and putting > > a little handhole in front of every house. How > > does this work? Are they using taps instead of > > splitters? If not, when they get a customer > > install order, do they pull his drop cable > > through all the handholes to a splitter? That > > doesn’t seem feasible. Are they dedicating a > > strand to each house and pulling the main cable > > out each time and splicing to that strand? And > > what if they estimate the take rate wrong, or a > > new house is built? > > > > There’s probably a simple explanation and once > > someone enlightens me it will be a Duh! moment. > > > > -- > > AF mailing list > > [email protected] <mailto:[email protected] > <mailto:[email protected]>> > > http://af.afmug.com/mailman/listinfo/ <http://af.afmug.com/mailman/ > listinfo/> > > af_af.afmug.com <http://af.afmug.com/mailman/ > > listinfo/af_af.afmug.com> > > > > -- > > AF mailing list > > [email protected] <mailto:[email protected] > <mailto:[email protected]>> > > http://af.afmug.com/mailman/listinfo/af_af.afmug.com <http:// > af.afmug.com/mailman/listinfo/af_af.afmug.com> > > <http://af.afmug.com/mailman/listinfo/ > af_af.afmug.com <http://af.afmug.com/mailman/listinfo/af_af.afmug.com>> > > > > -- > > AF mailing list > > [email protected] <mailto:[email protected] > <mailto:[email protected]>> > > http://af.afmug.com/mailman/listinfo/af_af.afmug.com <http:// > af.afmug.com/mailman/listinfo/af_af.afmug.com> > > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com>> > > > > -- > > AF mailing list > > [email protected] <mailto:[email protected] > <mailto:[email protected]>> > > http://af.afmug.com/mailman/listinfo/af_af.afmug.com <http:// > af.afmug.com/mailman/listinfo/af_af.afmug.com> > > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com > <http://af.afmug.com/mailman/listinfo/af_af.afmug.com>> > > > > -- > > AF mailing list > > [email protected] <mailto:[email protected] <mailto:[email protected]>> > > http://af.afmug.com/mailman/listinfo/af_af.afmug.com <http:// > af.afmug.com/mailman/listinfo/af_af.afmug.com> <http:// > > af.afmug.com/mailman/listinfo/af_af.afmug.com> > > > > -- > > AF mailing list > > [email protected] > > http://af.afmug.com/mailman/listinfo/af_af.afmug.com <http:// > af.afmug.com/mailman/listinfo/af_af.afmug.com> > > > > > > >
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