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DOCSIS 3.0 Channel Bonding and You

I’ve been a subscriber to Time Warner’s high-speed Internet service since we moved to Texas, largely because they were the only option we had when we arrived at our new home. Since then AT&T U-Verse has also become available (up to the 18 Mbps tier), but I’ve enjoyed pretty consistent and reliable service from Time Warner so I saw no reason to change — especially since AT&T requires a contract.

However, over the last few months our Time Warner connection has slowed to a crawww-w-w-wl. We’re on the Standard tier, which gives us 10 megabits downstream. That translates to about 1.25 megabytes per second of maximum download speed. Lately, though, I’ve been lucky to get anything faster than 400 KB per second. This is even coming from sites that I know have the bandwidth to serve up files as fast as you can take them, such as Microsoft (try downloading a Windows service pack to see what I mean). On top of that, downloading game demos and patches through my Xbox console or app updates on our Apple iDevices seemed to take a dog’s age.

Whenever I’d get suspicious that something was awry with our connection, I’d hop over to and check things out. Every time I’d get a report back that our line was humming along at 17-20 megabits, which is double what we pay for. This, I knew, was due to the PowerBoost effect. (PowerBoost is a cable broadband feature that gives you a burst of super speed for the first few seconds of any download.) That made it tough to get an accurate picture of what our true speed really was. But if I was testing out at near 20 megabits most days, surely my real-world speeds were pretty good too.


"Emphatically no, Brock."

Uhhh, yeah. Not so much. Quite by accident, after getting into a discussion on DSLReports about Time Warner’s upcoming upgrade from 10 Mbps to 15 Mbps on the standard tier (yay!), it was suggested to me that my slowness issues could be caused by congestion on the lines and that is actually a very poor benchmark of real-world speed. It was instead suggested that I try the speed and line quality tests at and Visualware. So I set off to do just that.

I was pretty annoyed to discover all those other speed tests reporting a usable real-world throughput of only 3.3 megabits per second, only a third of the speed I was paying for — and an exact match for the approximate 400 KB/sec I was seeing in various download scenarios. While my upload connectivity seemed pretty good (after all, how hard is it to deliver a paltry megabit of upload capacity anyway?), the download speeds were atrocious. Other users on DSLReports who live in the Dallas area confirmed that Time Warner’s lines are severely congested in this area, which means too many people are using the same nodes and overloading the QAM channels.

These folks also suggested a solution: get a DOCSIS 3.0 modem. At first I thought that was hogwash, since we’re only on the Standard tier and we don’t have any need for the DOCSIS 3.0 technology that would deliver the speeds offered by Time Warner’s 30-50 megabit tiers. But I was soon to learn an important lesson: no matter what speed tier you subscribe to, channel bonding — a DOCSIS 3.0 technology — is your friend.

Time Warner’s Dallas-area systems offer six downstream and four upstream QAM channels. If the channels are overloaded, a DOCSIS 3.0 cable modem can bond multiple channels together to provide one big pipe. That way, even if only a little data can get through each channel, bonding them together will allow you to push that data through multiple pipes at one time and thus work around that congestion. Only DOCSIS 3.0 modems can do this.

The old DOCSIS 2.0 modem that I was leasing from Time Warner, conversely, could only utilize one downstream and one upstream channel at a time and it’s forced to use the channel the cable company’s headend tells it to use. If that channel is overloaded, then you’re gonna see poor speeds, period — and there’s nothing you can do about it.

So, I decided, I’m going to solve this problem of slow speeds by purchasing a DOCSIS 3.0 cable modem. Time Warner wouldn’t lease one to me because I’m not a subscriber of their high-speed tiers, so buying a modem outright was my only way forward. As a bonus, purchasing my own modem gets me out of the upcoming new $4 monthly fee that Time Warner will soon begin charging to lease a modem from them. Faster speeds and a fee exemption? Sounds good to me!

It gets better. In another perfect convergence of circumstances, last week Time Warner updated their approved modems list to add a number of new DOCSIS 3.0 devices, including the [amazon_link id=”B0063K4NN6″ target=”_blank” ]Zoom 5341J[/amazon_link]. Rather than pay for the expensive Motorola SB6141, I can pay two-thirds of the cost and get the Zoom, and still enjoy the ability to bond 8 downstream and 4 upstream channels. Future-proofing indeed!

Channel bonding is go!

So that’s exactly what I did. We returned on Thursday night from a trip to Orlando and I didn’t really want to pay Amazon $9 to have the 5341J delivered on Saturday, so instead I went to Best Buy and picked one up after work today. When I got home, it was simply a matter of swapping out my old modem, calling Time Warner and reading them the 5341’s MAC address so they could provision it in their system. 15 minutes later the Zoom was showing a pair of solid blue LEDs on the front, indicating both downstream and upstream channel bonding was established. We were in business.

(Incidentally, it seems that Time Warner’s new modem lease fee is prompting a lot of subscribers to buy their own modems. When I called in, the first thing I heard was a prerecorded message saying “Have you purchased your own modem? Press 1 to speak to someone about activating it.” The benefit of this was that I didn’t have to wade through a phone tree to get where I needed to go.)

The new modem didn’t immediately deliver Internet connectivity, so I had to release and then renew the WAN IP address via my router’s control panel. Once I had done that, I had full access. Of course, I immediately went to run some more speed tests. This time, the results were much, much better: I was seeing a solid and consistent 9.58 Mbps down and 969 Kbps up, which is right there at the upper limit of what we’re paying for. And with all six downstream channels bonded, I’m not likely to see any hiccups, even once Time Warner boosts us to 15 Mbps down in the next month or two, as they are reportedly doing nationwide. Yes!

I learned an important lesson here about DOCSIS 3.0 and channel bonding. If you receive broadband Internet from a cable company (instead of, say, DSL or fiber), and if your speeds are utter crap, you might also want to consider a DOCSIS 3.0 modem if your provider supports channel bonding. It just might solve all your problems. And, for that matter, help you avoid paying an equipment lease fee!

18 thoughts to “DOCSIS 3.0 Channel Bonding and You”

  1. I’m in upstate NY and looking to do the same thing, D3 modem with standard speed tier. Can you confirm that your modem has successfully bonded channels? One thing that I’m hearing is that on the standard speed tier, TWC might not allow your modem to bond channels. If that’s the case, there is no advantage to buying a D3 modem. Very nice article by the way, can’t find much information on doing this.

  2. Nevermind, I found the answer to my question. Blue DS\US LEDs indicate channel bonding where green LEDs indicate only a single channel is in use.

    1. Yes, you are correct about the LEDs. Additionally, the Zoom 5341J has an internal status page (fairly barebones, but gets the job done) that shows channel bonding status. Here’s a screenshot of mine.

      Time Warner Bonded Channels

      Incidentally, Time Warner upgraded our area to 15 Mbps downstream a few weeks back (as they’re doing to the Standard tier nationwide) and we’re now seeing every bit of that, thanks to channel bonding.

  3. I’m in midcoast Maine running a new DOCSIS 3.0 Motorola 5680 modem on TWC “turbo” service 20Mbps down.. 2Mbps upload.. and I’m now getting 30-50Mbps down, and 2Mbps upload.. on my old Motorola 2100 modem, (standard tier) I was getting just at the edge of my 20Mbps down, and 2Mbps up.. but I was looking to lower my monthly bill, and bought the new modem for $127 +$20 for the 2 year warranty/replacement coverage from bestbuy.. I figure the extra speed, and $4 off my bill (and dropping the turbo ($5) at $9/month will pay for itself in less than 2 years.

  4. Thanks Chief! On I was getting 10-12Mbps down, through on 15 Mbps tier with Wow! service. I upgraded from D2 Linksys (BEFCMU10 I believe) to this Zoom 5341J. Testing after the upgrade indicates now seeing the full 15Mbps.

  5. I got a Motorola 6141 DOCSIS 3 modem to replace the Scientific Atlanta 2100R2 modem, but I have lost speed. I am not happy at all. I was getting 25 Mbps down before , and now I am only getting 14 Mbps down. What could be the problem?

    1. Probably what’s happened is that you aren’t getting Powerboost (or Turbo Boost, or whatever your cable provider calls it) anymore, since most if not all DOCSIS 3.0 modems don’t work with Powerboost technology. Many broadband speed tests will show you results much higher than your average throughput because Powerboost throws them off.

      In my case, line quality was so bad that even with Powerboost enabled I was only seeing an average of 3 Mbps throughput. However, speed tests like were telling me I had 18 Mbps down — perhaps because Powerboost blipped to that speed for a split second before trundling back down to a congested 3 Mbps level.

      If you are on Time Warner’s 15 Mbps standard package, 14 Mbps down consistently means you’re getting pretty much everything you’re paying for. Try a big download (like a Windows service pack) and watch your download speeds. Is it consistently 14 Mbps the whole way through? Then you appear to have a stable and high quality connection.

      If you really want Powerboost, you’d have to go back to a DOCSIS 2 modem like that 2100R2. But then you’ll have to deal with congestion issues that could make you actual download speeds much slower on average.

    2. Pete5668 may benefit from reviewing on cable modems and then checking the upstream power and signal-to-noise for his hookup by contacting his cable provider. I paid close attention to the number and type of splinters I had in my cable connection. Don’t leave us hanging on a negative.

  6. Nice review. I had already added the 5341J to my cart on Amazon as I usually take my time reading through the forums. It was your post that made me pull the trigger on completing the purchase. A few days ago I also picked up through Amazon the Asus (RT-N56U) n600 router and unfortunately I have not seen any reviews on a pairing the RT-N56U and the 5341J. Once I have both devices up and running, I will repost with an update. Wish me luck as comcast is the only provider available in my condo.

    1. Thanks for the feedback and good luck with your new modem + router combo. I actually have an Asus RT-N53 (the 10/100 little brother of the N56U) and have not had any problems with it. Quite the opposite, actually — it just runs for months with no need to power cycle. The firmware is not as customizable as what I’m used to with my WRT54GLs though, so I use the Asus as my wireless access point and a GL running Tomato as my gateway.

      That being the case, my Asus router is not directly connected to my Zoom 5341J, but I doubt you’ll have any trouble with yours.

    2. Its been 5 months since I have been using the 5341J, along with the Asus (RT-N56U) n600 and everything is working like a charm. Not a single reboot (knock on wood) and my speeds are fast and consistent. No lag issues from streaming from Amazon or Netflix, which was a previous issue from my old hardware. Modem setup couldn’t have been easier as I did not have to call Comcast cust svc. As for my new wifi router, holy Sh*t, this thing is just amazing. My signal is so much stronger than my older linksys model. I am very pleased with my purchase and the performance of my new additions. I’m sure there are probably newer hardware with more channels, but for my needs, this is enough for me.

  7. Thanks for the explanation. My SB6121 that I bought a year ago just started bonding for the first time a few minutes ago. My speeds aren’t any improved, I was getting the 30/5 I was supposed to be getting from Comcast anyway, but I was curious what bonding might mean to me anyway and found this page via Google.

    If I’d known that explanation about potentially getting better speeds when the pipes are clogged, I might have paid for the 6141, but the 6121 was cheaper and seemed to assure better compatibility from what I read, so I went with that. Not that I should really worry about it since I was doing fine un-bonded.

    Yay, more blue lights to go with the blue lights on my ASUS router!

  8. Very informative post. I use a VOIP phone service and I’ve noticed that my internet speed tests almost 80% lower if someone is on the phone (22mbps vs 5 mbps). I’m currently using an ancient DOCSIS 1.1 modem with Comcast Performance (20mbps) service. Would an upgrade to a 3.0 modem resolve these issues when more than one device is being used?

  9. Thank you. I have been working on my Asus and Surfboard all evening and could not get the bonding for uploading to engage. I thought it was something I was doing in the set up. Of course when I called Time Warner, they had no clue about anything since they no longer will be charging for the modem, but you would think since I don’t want to cancel cable they would give me a straight answer (oh well). My speeds are great in comparison but I still want to get the bonding on uploading so I think I will try your solution.

  10. Great article.

    I just replaced a clunky SB5101 with an SB6141, and so far, so good. Ping times used to hover in the 50s, and now I’m at ~ 15. Speed tests have me at ~22Mbps with both modems—I’m on TWC Turbo @ 20—though I decided to upgrade hoping for more stability than speed.

    BTW, you say

    “Rather than pay for the expensive Motorola SB6141 to get 6 downstream channels…”

    Every document I’ve read about the SB6141, and the SB6141 “Signal” tab says that it can handle 8 downstream channels, not 6. Was there an older model of SB6141 that could only handle 6? Just wondering.

    1. Good point. All the information I can find right now indicates the SB6141 supports 8 downstream channels. I can’t remember where I got the idea that it had 6, but it might have been from a forum user when I was doing my original research. That user may have been wrong. At the very least, it seems that the current 6141 does support an 8/4 channel configuration.

      Thanks for the tip! I’ll amend the article accordingly.

  11. I have a sb6141 love it since day one I have only had 6 bonded channels but when I woke up this morning it was now 8 Downstream Bonding Channel Valu. Why would they do this I know they have been around Syracuse NY fixing/replacing the nodes. Does this mean we might get a speed increase or is that just wishful thinking.

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