Blog Post

Comcast shows off a 3 gigabit broadband connection. That’s fast!

Stay on Top of Enterprise Technology Trends

Get updates impacting your industry from our GigaOm Research Community
Join the Community!

In an attempt to show that cable technologies can stay competitive with the fiber-broadband, Comcast (s CMCSA) chief executive Brian Roberts today demonstrated a 3 gigabits per second (Gbps) connection. He also talked about the next generation in video delivery during his keynote speech at the Cable Show in Washington DC.

Roberts used the 3 Gbps connection which he used to open an email and download a 4K video file. I’m sure the email didn’t tax the connection. However the 4K video download would certainly tax Comcast’s existing broadband cap of 300 GB per month (it is trialing other versions of the cap) given that a single 4K movie download weighs in at about 100 GB per movie. Yet, 4K is the next generation video delivery standard after HD and companies such as Netflix are already starting to deliver content in 4K.

On the broadband side, Comcast knows that to keep up with the demand for faster broadband networks, it will have to push the envelope on gigabit speeds. Google is building out gigabit networks in three cities, while AT&T has threatened to build on in Austin, Texas. Meanwhile private companies and municipalities are pushing their own gigabit projects.

So while Comcast currently delivers a top speed of 305 Mbps in some markets, showing off a multi-gigabit connection is important to show that cable technology can keep up with the fiber to the home build outs. The 3 Gbps connection was delivered over a DOCSIS hybrid fiber coax (HFC) network. But in the real world such speeds might be impossible without an upgrade to the next generation DOCSIS 3.1 technology.

As impressive as this demo is, the reality of deploying 3 gigabits per second may require a new technology (the coming DOCSIS 3.1 standard) as well as some hard thinking on how Comcast wants to use the spectrum available inside its cables.

The DOCSIS standard boosts broadband speeds by allocating more channels comprised of 6MHz of spectrum together to deliver broadband. So more channels, equal more speeds. But, those 6MHz chunks of spectrum also deliver between 2-4 television channels as well, so at a certain point Comcast has to decide if it wants to boost broadband at the expense of adding or delivering television channels.

5 Responses to “Comcast shows off a 3 gigabit broadband connection. That’s fast!”

  1. Hendrik Rood

    What if cable companies decide to allow content to flow over their broadband networks and allocate their installed bandwidth toward either their own video or internet downloads on-demand.

    There isn’t much difference anymore for a cable operator instrumenting its plant to enable Switched Digital Video and VoD/delay TV directed at a single user and a user who wants to look at channel 500, which no one else in the neighborhood views at the same time and a cableco instrumenting its plant for delivery over DOCSIS3.1

    The amount of bandwidth required doesn’t change, whether it is a 4K Netflix movie arriving over the pipe or a 4K SDV/VoD from the cableco.

    The key difference seems that IP flow runs over both the DOCSIS3.1 CMTS-platform and the included Edge-QAM interfaces (DOCSIS3.1 has E-QAM interfaces with CCAP), while their own IPTV injects the videostream with SDV directly into the E-QAM system, without using the relatively expensive routing platform of a CMTS.

  2. Transmitting a lot of channels at once in the traditional method may be overkill for a few hundred subscribers, but is more efficient when the number of subscribers are in the hundreds of thousands. With IPTV, each subscriber will require his own HD channel at the very least. This will involve a significant re-engineering of the network if Comcast has not done so already. While eventually everyone will simply be using the 1 gigabit of broadband as an IPTV link, it might be a bit further away for now.

  3. James Hancock

    Comcast and other cable providers need to:

    1. Switch to h264 (or h265) and exchange all of the cable boxes they currently have out there. (probably h264 for right now because cable card supports it, but not h265)
    2. Ditch all duplicate channels and only feed the HD version of each channel. Currently many channels are broadcast on their wire 3 or more times! Only broadcast the HDTV version and down convert for people that have old lame TVs. This will save a ton of SD channels and thus bandwidth.
    3. Switch to IP for video entirely and use IP multi-cast on their network so that only the channels that are needed at the specific neighborhood are sent to them over the wire. At any given time, comcast is broadcasting 300 channels to every neighborhood. By doing this, the vast majority of time that would be cut to perhaps 20 in an average neighborhood where the network demarks from fiber to coax.
    4. Float the total amount of internet bandwidth in the neighborhood and thus each person based on total bandwidth – tv channels being used.

    By doing this they would be able to easily get well over 3 gigabits in most neighborhoods without any problem at all. The problem is that the cable system is incredibly inefficient right now.