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.

fmd

Man-of-Leisure Well, Comcast could implement things further down the road. Things that they haven’t yet talked about publicly. Two reasons why it needs consideration: MoCA coexistence (the reason why the modem doesn’t go to 1.2 GHz in mid-split mode) and interference from the modem. Mid-split introduces in-home interference (iHAT tries to detect this). High-split increases the risk of interference in the home and between neighbors. They can deal with it like they deal with the interference from FDX modems.

I think I see some “it depends”…

Man-of-Leisure

fmd Well, Comcast could implement things further down the road.

I guess, but it sounds to me like they’ll probably stop giving out XB8s once they upgrade an area to DOCSIS 4.0.

New customers will get an XB10 in those areas, and existing customers who want the faster speeds will probably just be shipped an XB10.

Similar to Charter skipping over mid-split and going straight to high-split and 4.0, they aren’t bothering to support mid-split on modems that support it, even though they could.

jweaver

cypherstream signals are pretty bad there.

MacLeech

hex0101 Charter and Cox are pushing Xumo which is a joint project of Charter/Comcast and built on the X1 platform.

CommunityMember

MacLeech Charter and Cox are pushing Xumo

As I recall, also Rogers (Canada). Having a cheap streaming puck (BOM probably in the $20 range) to hand out like candy is an attractive path forward now that all the majors have cloud DVR solutions as part of their various migrations to IPTV delivery first. Linear QAM is not completely dead yet, but it is in hospice for most of the major providers (make it comfortable, but no further life extending active intervention). Comcast (unlike Charter) has still not offered a TV Provider app for the Xumo, which is unfortunate (the Xi6 is essentially a Xumo variant with the equivalent of a Comcast TV Provider app).

CommunityMember

Man-of-Leisure New customers will get an XB10 in those areas, and existing customers who want the faster speeds will probably just be shipped an XB10.

Or possibly the XD4 (for the few customers with their own gateway and want to continue to use it (most customers use the Comcast XB gateways)). However at this time tech visits are reportedly needed for D4.0 FDX multi-gig tiers (just like the earliest D3.1 roll outs required a tech visit). Given the potential issues with FDX, using techs to make sure that X-class service installs do not impact other customers is probably a good plan at this point. Eventually self installs (and shipment or store pickup) should be available for customers with X-class (if the incidents of real world impacts are minimal).

fmd

CommunityMember However at this time tech visits are reportedly needed for D4.0 FDX multi-gig tiers

Yes, Comcast requires a visit for now. The job:

Convert the home to IPTV
Make sure the modem is point-of-entry (may be anywhere in the home, but no splitters)
Remove any MoCA filter (needs capacity above 1 GHz, initially)
Check the signal. New tech, so everything must be validated

When Comcast is confident enough, FDX will become available as self-install. The installs will be less than ideal, but the tech has now been validated.

cypherstream

Even if they did FDX here, I’d have to really think hard on the switch. I live in the market that has the routing on the left. More hops and what the heck is going on in McKeesport. Pings in Central PA are twice as much as Eastern PA.
Every site is like this. Amazon AWS, Microsoft, Facebook, Apple, Google, OVH, Cloudflare.
Typical pings in one county over are 29-35ms, while to the east is 12-20ms.
And the thing is, both sites get about 600 down by 360 up… Comcast Business 500/300 plan. At home with SECV I’m about 9 hops to most East US sites and 10-15ms latency.

hex0101

fmd Supposed to also be running a new drop to ensure signal integrity. There is also no MoCA on the XB10. The customer is going to have to purchase another MoCA adapter to make up for the previous XB gateway that was acting as a MoCA client and run the MoCA network on a separate feed that is not connected back to the cable plant (an isolated in-home only cable network like how HomePNA worked for AT&T U-Verse TV).

CommunityMember

fmd When Comcast is confident enough ….

Given the mess (I am using that as a technical term) that I see in some residential locations, Comcast may never end up being fully confident for wide self installs that do not require a followup tech visit (while I am sure you, and a few other of the usual suspects on this site, could do it all, and do it right, do you really think most will be able to do so?). Hopefully any next gen iHAT variants will be able to not only test the residence for readiness, but also test interference from/to neighbors before full FDX activiation.

jweaver

fmd honestly, that will mean millions of customers will not be able to go FDX or have an X-Class tier initially. No splitters is also unreasonable and unrealistic for many.

fmd

CommunityMember Hopefully any next gen iHAT variants will be able to not only test the residence for readiness, but also test interference from/to neighbors before full FDX activiation.

That is their plan. fHAT tests the home, and nHAT tests between homes.

cypherstream

FTTH providers have techs do installs. It would be no different really.

fmd

jweaver The self-installs will be less ideal, so there may be a splitter and a MoCA filter.

CommunityMember

jweaver No splitters is also unreasonable and unrealistic for many.

With the migration to IPTV (and most customers are sufficiently happy with wireless for their satellite boxes and to use Pods for extension of the WiFi network (FD: I wire everything)), probably less than one might think (how customers are going to be migrated before they try to install X-Class is left as an exercise of the customer (and Comcast; I would hope they start to push the migration to IPTV harder faster in order to be ready for self-install X-Class)). Sure, there are people using MoCA for their own home networks, but that number is relatively small (although those that are doing so tend to fantasize they are among the many (sort of like CableCARD TiVo users fantasize they are among the many)). The real issue is that most consumers will have zero clue and ability to remove the no longer needed splitters (and/or install isolated networks), and while I have seen splitters installed (by (contracted) techs no less) behind wall plates, even out in the open splitters are beyond the capability of the average consumer unless they installed them in the first place.

I do agree that Comcast will likely end up needing more tech visits than they would prefer to complete the migration.

I would expect (hope) to be seeing a few “experience” sessions in upcoming SCTE/TechExpo conference, where we might get addition clue about the reality of deployments (while “where the rubber meets the road” sessions are not always the flashiness sessions, they tell you a lot about the real world deployments).

hex0101

jweaver Convert customers to IPTV. Now only the FDX modem needs to be connected to the incoming line. QAM’s days are numbered anyway. Weak Wi-Fi signal? Pull Cat6 to the room in the home with a weak Wi-Fi signal, or add an xFi pod. Techs can handle this during the FDX install.

Not sure about self installs, all those 1 Ghz splitters need to be removed or replaced with 1.2 Ghz splitters, MoCA filter has to also go. No way the average person will be able to figure this out. Once an address is FDX ready and has gone through a pro install, self install should then be possible in the future at that address, with fHAT and nHAT verifying proper operation during activation. (returning customer, new resident/homeowner, etc.).

Comcast tech had to come out my residence to activate my Gigabit service in 2018. Customer Service was not able to activate it remotely despite the fact that I already had an XB6 on the 300/20 plan at the time. Tech was able to use my existing XB6 and got it provisioned for Gigabit.

jweaver

CommunityMember XB10 not compatible with the wireless boxes though.

fmd

hex0101 Remember that Comcast requires access to downstream capacity above 1 GHz, because FDX OFDM is not currently in use (to not complicate things). When FDX begins to add to the downstream capacity, above 1 GHz is no longer required.

Most of their plants today are 1 GHz, so that also puts a limitation on available capacity up there.

They state in one paper that some homes will be allowed to be “worse” than others (the amount of attenuation), depending on what tier the customer wants. Higher tier > more OFDMA channels are needed = the modem needs to output more power.

X-500 (1xFDX OFDMA) and X-1000 (2xFDX OFDMA) are their highest selling tiers.

jweaver

hex0101 easier said then done to convert to IPTV. If Comcast is going to charge additional to run that Ethernet, many will just decline and cancel X-Class.

XB10 is incompatible with the wireless boxes.

CommunityMember

hex0101 Not sure about self installs, all those 1 Ghz splitters need to be removed or replaced with 1.2 Ghz splitters

With the (extremely) rare exceptions, those 1GHz splitters work well with 1.2GHz signals, they just are not “certified” (i.e. tested) above (usually) 1002MHz (you test to the specs your customers want, not the specs for some theoretical future usage). While I am sure some manufacturer did something “special”, I have seen no substantial changes in RF performance in 1GHz and 1.2GHz splitters.

Test-User

Since xFi Pods were brought up with regards to expanding coverage…

The Gen2 xFi Pods (2 Ethernet ports) are capable of Ethernet backhaul. Run a high quality Cat6 (not Cat6a, unless you’ve followed all official guidelines for Cat6a networking usage, which I’m under the impression that neither the Pods, nor the XB8 can accommodate) from the XB8/XB10 directly to the Pod. The Gen2 Pods are officially capable of 500Mbps. Although I’ve heard absolutely nil from anyone using them with an XB10. If you want the best coverage, using an XB8/XB10 and an xFi Gen2 Pod, Ethernet backhaul is the only way. YMMV

Saratoga66

jweaver You have stated the XB10 will not work with wireless boxes a number of times on this form. Do you have a link to the reason why?

I could see it not working with DVR type boxes that require a MOCA connection the gateway for the IP boxes to communicate with the DVR. If all boxes are simple IP boxes it should not require anything special to work. It’s no different than a TV, Roku, Apple or other device running the Xfinity TV app.

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