CableLabs, which tests and certifies DOSCIS equipment for all the majors (including Comcast), has stated that they expect the first D4.0(*) certifications in early 2024 (with the possible one-off's in late 2023).
That does not mean that there will not be testing and prototype experiments before that (some operators have even started now), but real deployments of commercially available CPE equipment across more than those small/limited tests, is not expected to start until 2024 (and even later for some operators in some markets). 2023 is thought to be a year of preparation (for at least Comcast), with the infrastructure being deployed that should be able to support the D4.0 future (i.e. R-PHY, vCMTS, etc.)
(*) Note that D4.0 includes lots of options (including the usual backward compatibility). Some operators will decide to implements FDX, some ESD, and perhaps some both, with all them able to claim D4.0 compliance (and sometimes marketing is all that matters).
Comcast uses the marketing term "10G" to refer to a host of network upgrades that are coming, including upgrades that they say will happen in multiple areas in 2023 that will result in "symmetrical multi-gig speeds."
With a successful test of full-duplex DOCSIS 4.0 complete, Comcast further outlined its plan for symmetrical multi-gig service to compete with FTTH
www.telecompetitor.com
One of the things that Comcast has been doing for awhile now are mid-split upgrades, which allow for faster upload speeds. In fact, they've increased upload speeds on just about all tiers in many areas, but they're nowhere close to being equal to download speeds. Their entry-level tier here, for instance, recently saw its speeds raised from 50/5 to 75/10 (with the usual over-provisioning of about 20% during off-peak hours). Their top (regular HFC) speed tier is now rated at 1200/35.
My understanding was that DOCSIS 3.1, even with mid-split, would not be capable of supporting at least 2 gigs in each direction (which is the
minimum that could possibly be called "symmetrical multi-gig"). To get those kinds of speeds, Comcast would also need to implement FDX.
This piece yesterday over at Light Reading does indicate that Comcast's mid-split upgrades to D3.1, combined with implementing full duplex (FDX), will enable symmetrical multi-gig speeds. Here's the key quote from the article linked above:
Under a mid-split, Comcast will expand the amount of capacity dedicated to the upstream – from a legacy range of 5MHz-45MHz to a broader range of 5MHz-85MHz. Using a DOCSIS network built to 1.2GHz with the mid-split and the use of Full Duplex DOCSIS (FDX) will put Comcast in position to roll out symmetrical, multi-gigabit speeds.
To some extent, this seems like a semantic debate. I was under the impression that if you added mid-split or high-split PLUS either FDX or ESD, then that is effectively D4.0. (Comcast is doing mid-split+FDX while Charter is doing high-split+ESD.) And I'm pretty sure that employing FDX (and maybe mid-split too) would require a new upgraded modem/gateway to access the top speed tiers.
IDK, maybe I'm incorrect in calling what Comcast will roll out before year-end 2023 "DOCSIS 4.0"? But it does appear to involve at least mid-split
and FDX (and probably other upgrades too, like R-PHY, vCMTS, etc.). So it's going to be a really significant network upgrade which, as I say, will likely necessitate a new generation of modems, whether those modems are still called D3.1 or instead called D4.0 (although note that the Telecompetitor story I linked up top here specifically mentions D4.0 modems and amplifiers).
What does all this mean for CableCARD TiVo users? Well, who knows. Maybe nothing. But given the kind of major network upgrade that Comcast will be doing in select markets next year, it would seem like an opportune time to reclaim that network bandwidth that's currently dedicated to QAM video and make the network fully IP, something which is known to have been on Comcast's (and other cablecos') long-term roadmap for years now.