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Good thing I bought and use my own router and modem. Although the interesting bit I noticed from the article was about the 'additional bandwidth' that gets allo

by oxalo 12y ago

Good thing I bought and use my own router and modem. Although the interesting bit I noticed from the article was about the 'additional bandwidth' that gets allotted. Meaning Comcast doesn't let you use all of your bandwidth.

sp332 12y ago
DOCSIS 3.0 modems support at least 171 Mbit/s https://en.wikipedia.org/wiki/DOCSIS#Speed_tables https://en.wikipedia.org/wiki/DOCSIS#Speed_tables But you have to share those channels with your neighbors, and then you have to share the back-haul lines with lots of people. So no, you don't get to use all the available bandwidth, but I don't think Comcast ever pretended that they weren't limiting you. If you upgrade to faster service they just click a button to bump your allotted speed up.
- Zelphyr 12y ago
  Wait. So a single DOCSIS 3.0 modem (which I own) can support 171 Mbit/s but Comcast gives me 50 for the low price of $70/month (not including TV)?
  - grecy 12y ago
    The modem can, but that doesn't mean the cabling, or the cable plant on the other end can. I work for a telco, we just upgraded all our cable and plant for 13k customers so we could offer 100Mbit down / 10Mbit up. The old max speed was 50/5. The cost was in the millions, even though the modems have supported it for years.
    - altcognito 12y ago
      So roughly $76 per customer. That cost could be amortized over, yknow, 6 months at $12. edit: You did say, "millions", but my point still stands. Unless it was 10+ million, which seems like a stretch. also: You don't have to amortize it over anyone in particular. You have revenue, you get to dictate how that revenue is spent.
      - grecy 12y ago
        It was a few "millions". Remember, too, that only a small percentage of customers have chosen to upgrade to 100MBit, so you can only amortize it over them. We did the business case beforehand and it didn't really make sense to be honest. We did it to keep the regulator happy(er) (we're not in the US).
  - jggonz 12y ago
    Yes, but how bad would you feel if you had been promised 171Mbps for a higher price and you only really attained 70-90 because you had to share the bandwidth with your neighbors? In your case, they could probably offer more than 50MBps, but they're playing it safe with 50MBps.
  - bri3d 12y ago
    It makes a lot more sense to evaluate an ISP based on the speed and latency they give you for the price (along with other factors like service, reliability, ethics, etc.), not how much of your modem's theoretical maximum bandwidth they're able to use. In order to be DOCSIS 3.0 certified, your modem does have to support 4x4 bonded channels (4 channels up, 4 channels down). But that does not mean your provider has the channels available or will provision them for you. DOCSIS 3.0 modems will happily provision themselves down to 1 6.5Mhz channel down, yielding just 38Mbits as a maximum. There's a lot more to it than just channel allocation, as well - the 38Mbit maximum for a 6.5Mhz channel is with 256QAM and a good signal-to-noise ratio, which depends on a huge variety of factors. Plus, even if you're getting plenty of channels allocated and have a good SNR, there's still the backhaul from your nearest point of presence into Comcast's WAN, the bandwidth across Comcast's WAN, and then whatever peering agreements they have to get across to the Internet at large. At any rate, I think this is a pretty silly argument against Comcast - it's like being angry that your Gigabit Ethernet switch doesn't give you 1000MBit access to some random server on the Internet.
    - munger 12y ago
      Unfortunately here in Louisville/Boulder Colorado, it's either Comcast or Century Link. I have tried both and done my own testing, and Comcast is still the best connection despite their price point. I could not agree more about latency. My first try with Century Link last year had 120ms latency which is terrible because Comcast was 15ms. CL upgraded my neighborhood loop and got to 20ms which is fine, but the CL upload speed is still crippled at an outdated 768kb/s where as Comcast I get 3.5Mb/s upload. I work from a home office so upload bandwidth is important. So since there is no other contender that has both good latency and upload speed I use Comcast for now.
      - selectodude 12y ago
        I hate Comcast as much as the next guy, but at least here in Chicago, they're very expensive and very good. I hate dealing with them, but paying $90/mo for 105/20 that works well is better than paying $60/mo for something that doesn't (RCN).
mikeryan 12y ago
Comcasts "bandwidth" is a shared pipe that includes your neighbors internet and a your TV channels. The vast majority of that bandwidth has never been dedicated to your private use.

by oxalo 12y ago

sp332 12y ago

DOCSIS 3.0 modems support at least 171 Mbit/s https://en.wikipedia.org/wiki/DOCSIS#Speed_tables https://en.wikipedia.org/wiki/DOCSIS#Speed_tables But you have to share those channels with your neighbors, and then you have to share the back-haul lines with lots of people. So no, you don't get to use all the available bandwidth, but I don't think Comcast ever pretended that they weren't limiting you. If you upgrade to faster service they just click a button to bump your allotted speed up.

Zelphyr 12y ago
Wait. So a single DOCSIS 3.0 modem (which I own) can support 171 Mbit/s but Comcast gives me 50 for the low price of $70/month (not including TV)?
- grecy 12y ago
  The modem can, but that doesn't mean the cabling, or the cable plant on the other end can. I work for a telco, we just upgraded all our cable and plant for 13k customers so we could offer 100Mbit down / 10Mbit up. The old max speed was 50/5. The cost was in the millions, even though the modems have supported it for years.
  - altcognito 12y ago
    So roughly $76 per customer. That cost could be amortized over, yknow, 6 months at $12. edit: You did say, "millions", but my point still stands. Unless it was 10+ million, which seems like a stretch. also: You don't have to amortize it over anyone in particular. You have revenue, you get to dictate how that revenue is spent.
    - grecy 12y ago
      It was a few "millions". Remember, too, that only a small percentage of customers have chosen to upgrade to 100MBit, so you can only amortize it over them. We did the business case beforehand and it didn't really make sense to be honest. We did it to keep the regulator happy(er) (we're not in the US).
- jggonz 12y ago
  Yes, but how bad would you feel if you had been promised 171Mbps for a higher price and you only really attained 70-90 because you had to share the bandwidth with your neighbors? In your case, they could probably offer more than 50MBps, but they're playing it safe with 50MBps.
- bri3d 12y ago
  It makes a lot more sense to evaluate an ISP based on the speed and latency they give you for the price (along with other factors like service, reliability, ethics, etc.), not how much of your modem's theoretical maximum bandwidth they're able to use. In order to be DOCSIS 3.0 certified, your modem does have to support 4x4 bonded channels (4 channels up, 4 channels down). But that does not mean your provider has the channels available or will provision them for you. DOCSIS 3.0 modems will happily provision themselves down to 1 6.5Mhz channel down, yielding just 38Mbits as a maximum. There's a lot more to it than just channel allocation, as well - the 38Mbit maximum for a 6.5Mhz channel is with 256QAM and a good signal-to-noise ratio, which depends on a huge variety of factors. Plus, even if you're getting plenty of channels allocated and have a good SNR, there's still the backhaul from your nearest point of presence into Comcast's WAN, the bandwidth across Comcast's WAN, and then whatever peering agreements they have to get across to the Internet at large. At any rate, I think this is a pretty silly argument against Comcast - it's like being angry that your Gigabit Ethernet switch doesn't give you 1000MBit access to some random server on the Internet.
  - munger 12y ago
    Unfortunately here in Louisville/Boulder Colorado, it's either Comcast or Century Link. I have tried both and done my own testing, and Comcast is still the best connection despite their price point. I could not agree more about latency. My first try with Century Link last year had 120ms latency which is terrible because Comcast was 15ms. CL upgraded my neighborhood loop and got to 20ms which is fine, but the CL upload speed is still crippled at an outdated 768kb/s where as Comcast I get 3.5Mb/s upload. I work from a home office so upload bandwidth is important. So since there is no other contender that has both good latency and upload speed I use Comcast for now.
    - selectodude 12y ago
      I hate Comcast as much as the next guy, but at least here in Chicago, they're very expensive and very good. I hate dealing with them, but paying $90/mo for 105/20 that works well is better than paying $60/mo for something that doesn't (RCN).

mikeryan 12y ago

Comcasts "bandwidth" is a shared pipe that includes your neighbors internet and a your TV channels. The vast majority of that bandwidth has never been dedicated to your private use.