So I am not quite sure of the differences. I have read that DSL is fed into the home via the phone line, and cable is, of course, through the cable jacks. I currently have a 30Mbps cable connection but am forced to downgrade to a 6Mbps connection due to the service not being available where I am moving.

What are the main differences? For example, as I said I have a 30Mbps connection now that costs $30/mo, but the 6Mbps DSL service I am being forced into is going to cost $35 (different location and different company)! I figured the prices would be similar but was surprised that was not the case. Are there some underlying differences between the two services that may justify such a difference?

If I have a 6Mbps DSL line, will a 6Mbps cable line be the same speed? I realize there are circumstances to consider when making this judgement (i.e. whether you have a dedicated line to your home or a community line), but assuming the situations are exactly the same are they similar?

Also, why have I seen some internet providers offer packages upwards of 105MBps, while a company like AT&T has 'Extreme' package (or whatever the fastest may be called) only on the order of 18Mbps? Is cable capable of speeds that much greater than DSL?


DSL and Cable are generally regarded as equivalents at a given speed. 6mbps cable and 6mbps DSL offer the same performance (for practical purposes).

There are some subtleties behind the scenes; some modems and ISP devices handle congestion better than others.

DSL is limited by distance to the central office a lot more than cable is; as a result many cable ISPs can offer higher speeds to a larger amount of customers. However, if you have clean phone wiring and are relatively close to the central office, DSL can be very competitive with cable.

Cable has one main disadvantage; it is more prone to congestion at peak hours than DSL if a provider does not build enough capacity on their network. DOCSIS 3.0 was designed to help with this issue.

ADSL connections often use an ATM backbone and/or PPPoE which adds some overhead and may provide slightly lower than advertised speeds and/or cause performance problems for time sensitive applications (see TC-ATM patch for more details). VDSL is fed by fiber backhaul and does not have this issue.

  • I provider of the DSL line in question is actually AT&T. I was told by them, when I asked a similar question regarding congestion, they said that each customer actually is given a dedicated line thereby facilitating greater speed within the home based to a similar cable service that is not dedicated. – sherrellbc Aug 18 '13 at 19:38
  • This is an old story, albeit partially true. Cable networks can be congested at peak hours, but only if your ISP has not built enough capacity. DSL can still be congested higher up in the infrastructure, so it's not a "dedicated link" to the internet either. – cloneman Aug 21 '13 at 0:06

From my understanding, 30 MBPS was for your whole neighborhood. So if no-one used the internet, you get 30. DSL is "dedicated" but if every one maxed out their dedicated amount, their trunk lines get maxed out and you get slower speeds.

Also, cable usually has less upload speed than DSL. And I do believe DSL can go faster than cable because cable is not typically fiber based, where phone companies are. It's just how close to the fiber (optic lines) are you. That is, is it fiber to your house, or fiber to a box miles away with copper in between, and how many miles matters.

We have always been happier with DSL and we have heard complaints from people with cable who tried to do things like uploading larger files for business, or run VOIP, or other out of the box things. People with DSL seems to have less problems doing such things.

Cable is great for the average home user. DSL shines with "power" users. (Personal opinion, not fact)


Typically in most areas, cable is able to get you speeds that much higher. It does come down to a difference in the technology and hardware, and cable typically comes out on top. When you move to an area where cable is not an option, I believe that DSL connections are leveraging hardware and lines that are already in place for phone systems - hardware that is designed to be cheaper to implement. Cable is more designed around speed, but a cable company isn't going to invest in laying lines to an area unless they expect to get a return on that investment with a large customer base. It's worth noting that normally the speeds advertised by ISPs include "up to..." since they can't guarantee you'll always get a specific speed (doing so would require that they have more network capacity than is actually used, which would not be a good budgeting decision for them). So take that advertised speed with a grain of salt, and consider it more of an average speed to expect on a good day.

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