FDX/Unified DOCSIS

fmd · 2025-02-13T20:05:09+00:00

While we wait for the announcement that N+X deployment has officially begun... Unified is the new version of FDX that has downstream going all the way to 1.8 GHz (currently limited by old taps). The return still stops at 684 MHz. Comcast has presented this spectrum layout to begin with: This is sufficient to offer symmetrical 2 Gbps. When more of the legacy channels go away, higher speeds can be offered. 3.1 modems that get FDX-L (limited) firmware can use the FDX channels.

crucialcolin

hex0101 Can’t really tell, as this Harmonic Ripple housing could contain either a Pebble-1 (mid/high split) or a Pebble-2 (FDX) RPD.

Ah yeah I just thought of that myself. Well the guy I saw working on one the amps which had previously been an Starline MB120 appeared to have a module with much bigger fins on it indicative of FDX.

Moffetts

The amps are the telltale sign of upgrades with this go around. That wasn’t necessarily true with the midsplit deployment.

bigcoda

crucialcolin work has begun as my Xfinity service is currently out. So far it doesn’t look like they are touching any nodes/amps today in my neighborhood though.

Nice! Yea Comcast completed the second day of upgrades in my neighborhood yesterday. I didn’t notice any work trucks or crews in the area, but my internet was going down intermittently throughout the day. Once they sent me the text, letting me know they completed the work in my area, it’s like nothing ever happened.

crucialcolin They got a small section of sidewalk dug up on one of the streets. I’m thinking for additional fiber. I’m a little surprised they shut service off to the entire neighborhood off just to do that.

Hmm interesting, I think you might be correct.

bigcoda

crucialcolin Is this an FDX node?

Yea like others said, you really can’t tell, I know some of them were being painted white in the beginning. But I don’t know if the white paint indicates which node you have, or there just trying to save a few bucks buy not painting them white now?

Moffetts

All of the harmonic ripple nodes are white. The Arris OM6000 nodes were silver or white, depending on their age.

bigcoda

wl415 The aerial amplifier in the alley behind my house in Boulder, CO was just replaced yesterday. It seems they kept part of the old housing. Since then, there have been constant outages and speed tests have since gone to shit. Never had an issue before. Comcast is being used as WAN failover (Quantum Fiber is the primary ISP), so it’s not a major issue for me. Is this FDX?

Yea that definitely looks like a FDX CommScope housing. I’m surprised your area wasn’t already upgraded to FDX, since Colorado was one of the first FDX DOCSIS 4.0 areas?

clocks

crucialcolin I see a lot of those around me. We are currently midsplit.

cypherstream

Moffetts in Philadelphia near south street I saw an OM6000 painted brown! If I wasn’t walking with my wife I would have taken a picture.

crucialcolin

bigcoda Nice! Yea Comcast completed the second day of upgrades in my neighborhood yesterday. I didn’t notice any work trucks or crews in the area, but my internet was going down intermittently throughout the day. Once they sent me the text, letting me know they completed the work in my area, it’s like nothing ever happened

Yeah mine was out between 8am-2 pm because of that line work.

It’s interesting since then my Internet seems to be working again while they are still driving around opening and making changes to amps. The Xfinity outage page shows they are working in my neighborhood until 7:30pm tonight. Maybe they are just swapping FDX modules into the old amps or they are working on the plant while it’s live (powered on) in such a way as to not cause a noticeable cascading outage to end users. It’s definitely weird 🤷‍♂️

crucialcolin

clocks see a lot of those around me. We are currently midsplit.

Yeah was currently mid-split as well until they started this new round of work. I’m thinking a Pebble-2 upgrade module is going in there.

I have seen other white harmonics nodes in use in a couple spots that still have above ground utilities(a rarity in my city).

hex0101

Moffetts Early Harmonic Nodes were Silver

rPHY/vCMTS in 2019! Some Comcast customers had it!

crucialcolin

Damn not sure they replaced the line extenders on my street yet but the roll off with the OFDM channel around 1ghz got worse.
Went from -10.2 dBmV to -11.5 dBmV

We’ll see what tomorrows work brings i guess…

I believe frequencies will move around when they enable FDX too. Off hand isn’t one of OFDM channels supposed to show up under 350 mhz? Not to mention having more then just one?

wl415

bigcoda FDX started two hours South in Colorado Springs, which has newer infrastructure. My neighborhood in Boulder never even had mid-split to begin with. I have a STR up in the mountains that has had it for two years now, but still don’t have it at my place in Bay Area. Boulder’s infrastructure is very old, and much of the utility service (like mine) is delivered from a rear alley that has had undergrounded service. The entire city is like that, since the building department required homeowners to foot the bill for utility burial with renovations and new construction back in the 90’s.

cypherstream

hex0101 wow pre covid! Bleeding edge back then.

I wonder if they standardized on white for training techs. “If it’s white, it’s a node ,if it’s silver it’s an amp”.

Spectrum has even been installing some blue gear. Blue taps and hardline splitters apparently mean it’s rated to at least 1.8 GHz. Quick visual to know what’s done or not. https://atx.com/products/taps-passives/gigaxtend-xs-series-2ghz-taps-passives/gigaxtend-2ghz-hardline-passives/

Color coding ftw.

Moffetts

hex0101 Wow that is vintage, like prototype stuff.

crucialcolin

bigcoda A little FDX goodness being put in right across the street:

crucialcolin

Signal seems better now with the upper freq by replacing that line extender.

Of course they are still running in mid-split mode with a single OFDM channel. It will be interesting to see how long they wait to enable FDX here.

cypherstream

They do look nice with the color coded cables. There certainly are more of them from the lid to the base in FDX / Smart amps.

fmd

crucialcolin An observation (because of the thread title), the amplifier is not a 2nd gen Unified amp (1.8 GHz). I’m eager to see more deployment pictures of these.

crucialcolin

fmd An observation (because of the thread title), the amplifier is not a 2nd gen Unified amp (1.8 GHz). I’m eager to see more deployment pictures of these.

Interesting. I did not know there was a difference. Anyways it looks like my cable plant is staying 1.2 GHz since they just put these in today. Not Extended Spectrum (ESD).

My guess upgrading to 1.8 Ghz would require replacing a ton of taps or passive devices. An expensive Comcast likely doesn’t want to do.

I know for a fact the taps in my neighborhood are all rated to 1.2 GHz just don’t remember the brand. 1.8 GHz is probably limited to new builds only in legacy AT&T broadband areas(northern California).

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