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.

hex0101

cypherstream In Seattle Harmonic Ripple-1 nodes (with pebble-1 RPD) were being installed as far back as 2019 (prior to COVID pandemic!)

From a tech in Seattle- August 4th, 2019- RPHY cut in
Services were tested on the new RPHY node the day prior to cutover

MacLeech

Moffetts Well yeah, cable companies are in a perpetual upgrade cycle. I don’t know what makes them choose FTTH over HFC in new builds in 2025, but, they have no issues with “doing it all over again.” That is how they have always operated.

Most residential internet service providers are in a perpetual upgrade cycle, even fiber. Verizon FiOS went from BPON to GPON to now NG-PON2. ATT went from ADSL to ADSL2+ (fiber to the lawn fridge) to XGS-PON. Before that dial-up migrated through multiple variants of V.xx from 1200 through 14.4k, 28.8k, 33k, to 56k.

hex0101

MacLeech ATT went to GPON. (and maybe BPON, long time ago now.) GPON only OLT’s are still active in many areas. Mid-split 2 Gbps (speed tiers) and FDX 2 Gbps (plant capabilities) beat GPON in terms of speed only.

meerkathalon

We have scheduled maintenance on October 1st. Probably nothing out in the field though given the time of day.
What’s the theory behind legacy subsplit going to FDX gen 1 as opposed to straight to gen2?

cypherstream

meerkathalon Its rumored that if you are still legacy you might go FDX now. But like its been said, Cable is in a perpetual upgrade cycle, so who knows. There’s still new areas finishing up their HFC mid split builds. Maybe Commscope can’t crank out FDX amplifiers fast enough.

meerkathalon

cypherstream would gen 2 FDX be the point where they expand X-Class to a 5 Gbps tier? Or Is gen 1 already capable of that with changes in spectrum layout?

hex0101

meerkathalon 5 Gbps down and 3 Gbps upload is likely possible with 1.2 Ghz plant spectrum operation so the current FDX amps would be fine.

jweaver

Just had an overnight maintenance though it only applied to TV, but nothing on the TV side ever went out.

cypherstream

At SCTE Tech Expo 2025 in DC this past week, tons of 1.8 GHz stuff was shown. Smart self leveling/adjusting amps, lots of AI. Docsis still has a lot of legs in it.

kmax

So how does an email saying…

“Enhancing the Xfinity network for faster, more reliable speeds” With a date…

Just seems odd.

Moffetts

What is odd about it?

kmax

Absolute 0 nearby work.

MacLeech

kmax It could be done further upstream, like in the hub or the sites it connects to. You won’t always see the work being done.

hex0101

kmax Focus on your node and the road ahead! Just because you don’t see mid-split/FDX service active nearby doesn’t mean that you won’t get it! Also, depending on what you are looking at, you may not be up to date. For example, looking for hints of upgrade activity on the FCC broadband map, which is 9 months behind as of right now.

kmax

Perhaps maybe a transition to vCMTS? Still on at 690…channel 37 for the OFDM.

hex0101

kmax Not looking good.. 193 is what you want to see. Could check the CMTS MAC for a definitive answer. What was the date on the email if you happen to know by chance?

fmd

kmax What modem do you have? If it has FDX-L firmware (Comcast has confirmed that their modems have it/will get it), it can bond one of the FDX OFDM channels, if your plant gets the FDX upgrade. You would be the first here to post that channel config. 🙂

kmax

Today…10/3.

Oh, edit…work on 10/10.

Everything here is underground. and well won’t get into the pedestal conditions.,.,.

hex0101

kmax Oh Ok. Well for now, there will be no changes to the plant’s spectrum layout or channel ID numbers. The downstream OFDM will remain with ID 37 until the new rPHY node is cut-in. 690 Mhz with a channel ID of 193 will be the config that is run directly after node cutover.

Congratulations for being on a node that has been selected to receive plant upgrades! Either mid-split or FDX.

Expect crews in the area working on 10/10, unless there are unforseen issues like weather conditions. Feel free to take some pictures!

Aceq2jot

hex0101 What does the 193 mean. Could you clarify this for me as I see it on my mode. All the nodes are being upgraded in my areas and I have seen a truck a few times this week in my area with a fiber splicing trailer behind it.

kmax

XB8 CGM4981COM_8.1p8s2_PROD_sey

A very long story (I’ll try to shorten)…we’ve had “issues” just random reboots. Nothing earth shattering but still a PITA so after a bunch farting around with CS they finally did a truck roll. Tech said, yeah…line from pedestal to your house is having some issues. Then he says…“Read through previous notes, noticed you asked for an XB10 (Which I had). He said a call came over needing one for a 2 gig customer and 2 gig is required.” So, it is somewhere around here lol but he wasn’t really up on it if you know what I mean.

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