Subscribers per pfp

dslwanter

How many subscribers per pfp? I know theres like 3 sizes.

xpxp2002

Legacy GPON was typically 32/1. XGS-PON builds often use 64/1.

dslwanter

xpxp2002 what does that translate to per box?

xpxp2002

dslwanter So each splitter is 32/1 or 64/1. Up to 32 or 64 subscribers per splitter. Those all share the same light back to the OLT. Multiple splitters can be used to reach larger service areas, each having their own dedicated strand and OLT port. I'm pretty sure they can fit 2 splitters in one PFP box, but not sure if that's only true with 32/1 builds.

I can't say that I've personally seen AT&T do it, but Windstream will sometimes run parallel fiber strands with two terminals on each pole/handhole in dense industrial and commercial areas in order to ensure adequate PON ports and bandwidth are available.

In a residential neighborhood, it would be more likely that OSP engineering would determine exactly how many PFPs, splitters, and terminals are needed to go 1:1 if they build to be able to service every household and scale density accordingly. They seem to reuse existing ROW where DSLAMs are placed for the PFP. I've often seen them pole-mounted with AT&T, either next to the crossboxes and DSLAM boxes or simply out in the field if there is no existing RT/DSLAM nearby. Windstream seems to always ground-mount theirs. I've literally seen them in the ROW in the grass along a road where there is no existing RT.

Also, when AT&T converts GPON to XGS-PON, they will do an overlay with a new, dedicated XGS-PON splitter, even though wavelengths are different. Everyone already patched into the GPON splitter stays until they upgrade to an XGS-PON tier or get moved due to a trouble call. I don't think they've fully decommissioned any converted GPONs yet, but I'm sure that will eventually happen. And my understanding is that converted areas become 64/1, so one XGS-PON splitter is installed for every two GPON.

dslwanter

xpxp2002 yes, this pattern l have already noticed with the pfp placement near existing copper distribution but it seems to be matching crossboxes not just remote terminals. I am trying to calculate how many connect per box. The box servicing the areas around us seems to serve around 216 homes based on where its available in 3 adjacent developments. There is a larger dual door pfp on 46 near dollar general that i think services more. Above the one that services 216 there are there splitters above it before about 3 reels drop down the pole to the pfp. They are starting in the development accross from us so trying to calculate if we might be in this build if its a dual door pfp by my calculations would service about 432 connections.

LightSpan

You can have up to 832 single fibers in a double door . This one was a telco rack mount for a remote site in a subdivision . The Office feed fiber is a 288 , the distribution feed is a 576 to the houses .

SpottedCat

My PFP is on a small plot of land next to a VRAD cabinet, and also what looks like an underground vault with an air conditioner on it. This is what feeds analog phone lines in the area, and during widespread power outages, like after a hurricane, AT&T would wheel out a generator and plug it in to keep services running.

It is my understanding that PON networks don’t require power in the field, right? So the fiber uplinks in that PFP go straight to the central office a few miles away and service won’t go down during an extended outage?

I’m curious because the underground vault I mentioned looks like it could have active OLT equipment in it if they decided to put it there.

LightSpan

SpottedCat That is correct , no power is needed . The splitters are passive . This is the same as the under ground vault just above ground . In the back ground is some series 5 (SLC5) that by now has been turned down .

SpottedCat

LightSpan Does AT&T plan to going to keep these remote sites powered up as is, or abandon all the active stuff and just leave the PON cabinets?

I’m imagining the cost savings from shutting down all the active equipment and just leaving the passive PFPs everywhere, but there could be a benefit to active monitoring equipment in the field too.

LightSpan

SpottedCat They will keep power if there is a GPON ROLT ( Remote Optical Line terminal ) if the feeds are to far out for the office OLT , they will keep power . I have been retired since July of 2024 . I assume there plan has not changed .

dslwanter

Confirmed we are on this build. They were out last Friday surveying our pedestals and I had a bs with the 2 in our yard. They said roughly 3-6 months for service. I can see this being one large pfp or 2 smaller ones. None of the nearby pfps have power to them but ill keep my eye out. We are about 3.5 miles from the CO and our DSLAM was RT based.

SLC_96

PFPs do not have any electronics so there wont be any power connected.

Near me there are many locations where the optical splitter was installed in the existing copper cross box.

dslwanter

SLC_96 thats what I figured on the power. We never saw vdsl so if that ties back to the vrad architecture and some sort of conversion process it wont matter here. Most areas around here are coming straight from ADSL with some COs that were setup for ADSL2+. That seems to be the pattern here as well with the crossbox to pfp placement. If thats the case, it will be a small pfp for our development and probably a larger one for the adjacent development as it is about double in size plus the main road leading to both developments. Im just glad hell is in fact finally freezing over. Even thought the cable monopoly we have had forever also converted to xgspon, well they are running gpon over it but still, it will be great to finally have a choice and potentially save if I move from verizon for mobile as well.

SpottedCat

What amazed me is how the cable companies (in particular, Comcast) has had years to deploy PON and be more competitive with companies like AT&T and Verizon, but they instead keep nursing their expensive DOCSIS tech, even installing coax into new housing developments in the past few years when fiber should have been the obvious choice.

DOCSIS 4.0 is really cool tech and it’s amazing how they can get so much bandwidth out of existing coax but in the end it still requires tons of active equipment in the field and uses copper-based cabling which is vulnerable to corrosion and lightning. They really should have pushed more to PON in the last decade.

xpxp2002

SpottedCat I think a lot of it was just typical short-term planning where they were more worried about what the next quarter would look like to Wall Street versus making the more difficult, but appropriate decision to spend a little more capex in the interest of long term investment in keeping the business competitive.

Instead, they’re now caught flat-footed spending more when material and labor costs are higher to basically forklift the entire plant from CMTS to tap anyway, just to breathe another decade of life into HFC instead of doing it to catch up and future-proof in one step. It’s absurdly short-sighted. I agree that D3.1 ESD and FDX, and D4 are cool tech. But it’s an expensive stopgap that will leave them just as far behind when they’re done as they are today.

Charter is doing high-split where they open up ~250 MHz of upstream and have another ~1-1.6 GHz of downstream spectrum on the wire, and even when they’re done (expected 2026-2027) they’re only going to be able to offer 5 Gbps down/1 Gbps max in most areas. Some markets that got their first-phase upgrades will likely max out at 2 Gbps down/1 Gbps up. XGS-PON has been broadly out in the field for at least 5-6 years and can support symmetrical 5 Gbps on typical 64/1 splits (AT&T implementation). I believe CenturyLink was even pushing it to 8 Gbps down/up in some of their plant. I’m not talking max capacity of the PFP or anything – this is a per-customer service offering. Now, imagine having the foresight to witness this in real world implementation, then being Charter or Comcast and instead choosing to spend billions to finish with a plant that is already guaranteed to be less capable than your competitors can be today.

They’re going to finish and then have to start all over again. I’m sure investors will be thrilled to see more capex being poured into another massive OSP upgrade project when they have to immediately turn around and start upgrading CMTS and nodes again, or pull the fiber (with even higher L&M costs) that they could have and should have done what will then be a decade later.

dslwanter

SpottedCat I often felt the same way. Almost like those at the top completely ignored any technical insight and lacked knowledge. In their eyes, replacing the system with fiber would be a complete rip and rebuild so to the non technical deep pocket that seems like a steeper investment. They probably felt just milk the cash cow monopoly as long as possible. When in reality it cost them more to keep pumping money into the workhorse rather than breeding the new workhorse. Very short sighted to have buried coax and ran fiber all the way to a hfc node only to realize gpon was a better choice with an easy upgrade to xgspon when needed.

MacLeech

dslwanter

dslwanter problem is they’re have to keep pumping money into upgrades of the existing system for a decade while they overbuild it with fiber and migrate customers over. Meanwhile during that dual network support period they have to maintain both while not charging customer any more than their current fees. It’s not rip and replace. It’s overbuild and migrate. See FIOS and Altice as examples.

dslwanter

MacLeech true on the rip and rebuild clarification. That’s what our local cable monopoly is doing. They stopped for the most part at DOCSIS 3.1. They actually went the xgpson route instead of milking into docsis 3.1 fdx or 4 here locally. Spectrum, the other cable monopoly in our market, on the other hand is and is now facing pressure due to Omni, Lumos, and AT&T.