Comcast’s latest hybrid broadband test teases an end to slow uploads

Chris Davies - Apr 22, 2021, 9:09am CDT
Comcast’s latest hybrid broadband test teases an end to slow uploads

If there’s one thing working from home has taught us over the past year, it’s that we probably snack too much; if there’s a second thing, it’s that your home internet connection can never be too fast. With fiber slowly spreading, Comcast is showing off the next-generation of its hybrid-fiber coaxial (HFC) network technology, and in the process promising a fix to one of the more frustrating aspects of home broadband: comparatively slow upload speeds.

Typically, ISPs love to shout about their download rates. Less common, though, are boasts about upload speeds, since they’re usually a fraction of the pace. That’s traditionally not been such an issue, as people tend to download things – such as streaming video – more than they upload.

While we’ve been working from home, home-schooling, and getting onto more and more video calls, however – not to mention playing streaming games in our spare time – the need for more upload capacity has increasingly become obvious. That’s one big advance that Full Duplex DOCSIS will bring, Comcast says, though there’s still a little time to wait before your friendly Xfinity sales rep will be pestering you with calls to upgrade.

Right now, the first successes are in the lab still. Comcast has been working with Broadcom on the first Full Duplex DOCSIS system-on-chip (SOC), compatible with the DOCSIS 4.0 Full Duplex standard. Though there are a few benefits to that, one is the ability to “dramatically increase upstream speeds,” Comcast claims, without sacrificing download speeds in the process.

We’re talking multi-gigabit rates in both directions, in fact, which is going to come as welcome news to anybody paying for the maximum cable internet rates right now but finding their upload tops out at around 10 Mbps.

The test involved Comcast labs in Philadelphia and Denver, the company says, with throughput rates exceeding 4 gigabits per second (Gbps). It’s a big jump over the symmetrical 1.25 Gbps rates Comcast announced it was achieving last October, and it’s expected to get faster still as the system is optimized. It’s part of what the internet provider industry is referring to as the “Path to 10G”: a recognition that, as with so many things, more speed is going to be required in the years ahead.

One big advantage is that the hybrid-fiber coaxial approach means Comcast will be able to use much of its existing wiring, rather than install brand new connections to each subscriber. For now, though, patience is still required. Expanded testing of the system is on the schedule for later in 2021, but there’s no public timescale for when it might see a commercial launch: Comcast is clear to point out that this is a multi-year initiative, so don’t hold your breath.


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