Scott Mueller's Upgrading and Repairing PCs Forum

My father recently switched to a cable ISP with a 20Mbps down residential plan and was using DOCSIS 2.0 modem. He recently started have a drop in speed and after talking to a costumer support rep he was told that his problem was that he needed a DOCSIS 3.0 modem in order to receive the advertised speed. He was concerned if the new modem would be compatible and if it was really needed to receive his full 20Mbps.

I told him that all the DOCSIS specs are standardized and backwards compatible and that I was pretty sure that a DOCSIS 2.0 modem was perfectly capable of handling the data rate he was paying for (not that he should realistically expect to see that speed all the time). I told him that if his modem was an issue it wasn't due to the DOCSIS 2.0 specification but do to hardware failure.

After consulting the DOCSIS® – Project Primer I see that the DOCSIS 2.0 spec will handle up to 27Mbps *upstream* so now I'm wondering...what are (if any) the real world benefits of a DOCSIS 3.0 cable modem for a residential or SOHO user?

-Evan

I love my Surfboard 6120.

I suspect he will still be dissatisfied however. I don't think it is the modem.

I know it isn't the modem (or at least the DOCSIS version) but it is easier for the service provider to send out (or have the customer pick up) a replacement modem rather than determine what is wrong with the network between his house and their building(s). His service provider has a history of *their* network being unreliable in his neighborhood. They don't get enough reports because most of the residents are retirement age or older and they don't report poor network conditions enough.

I was wanting to get a better understanding of the benefits of DOCSIS 3.0 over DOCSIS 2.0 (the same way you would explain how a 1Gbps network switch is better than a 100Mbps network switch and under what circumstances the former is more appropriate).

My father asked me why/if he needed the new modem and told me what the ISP phone rep. said and I said "I'll just post it on the Scott Mueller forum" then let him read the response. I have a feeling someone here knows more about this than me. <g>

-Evan

Having worked for a service provider in the past, albeit long before these fantastic speeds even became a thought, it was always a common practice to blame the customers equipment, ESPECIALLY if they had a router rather than think there was or is anything at all wrong with the service providers network infrastructure.

I'm sure that is still a common practice, even though the % of people using routers is much higher now than it was 8 years ago when I worked for that provider.

I'm sure this is of no help, but, just wanted to make you aware, you must be presistant in your contact with them about getting out to check the lines in your area to find the real problem, and to stop blaming YOUR equipment.

Cable companies generally provide the cable modem for you. Its included in the price of your service. So why worry about it?. Just take the cable modem that the company provides.

I'll give you a good reason to worry about it. <g>
I recently upgraded my service to Comcast's extreme 50 (50 down/10 up). I really like it. I know another guy named Steve <g> that upgraded shortly after I did. I was given a different modem than he was and my speed was much higher than his. When he finally talked Comcast into giving him the same modem that I had his speed also went way up. We also had to upgrade to gigabit routers to get the speed we were paying for.

Thank you Mike for posting that. What I was looking for originally was an explanation of how a DOCSIS 3.0 modem differs from a DOCSIS 2.0 modem but in hindsight I probably didn't word it very well. It was never a question of *if* you should use the newer modem. It was a question of what benefits does an end user gain from using a modem that meets the newer specs.

-Evan

Pray tell, what router was you given?

My point was that he didn't want to upgrade his older cable modem to the newer version. I was saying basically, "if your service provider wants to give you an newer modem to make your service faster, why question it?."

Now I see though that he was just looking for an explanation about the differences between the old and new modem.

Arris TM702G

That's *exactly* what I was looking for.

I was simply asked "is there any reason I should or shouldn't upgrade to this leased DOCSIS 3.0 modem?" I said "if they are offering it to you as part of your service, then take it. That modem is built upon the DOCSIS 2.0 specs." Then he asked "so what's the difference?" Which is why I asked here.

-Evan

DOCSIS cable modems use 6MHz channels that can carry up to 38Mbps downstream or 27Mbps upstream. DOCSIS 2.0 and earlier allow using only a single channel each way, meaning you would be limited to 38Mbps maximum down. DOCSIS 3.0 allows for bonding multiple channels, and since most DOCSIS 3.0 modems use 4 bonded channels down that would allow up to 152Mbps down. While those are the maximum figures, what you really get depends on your provisioned rate (i.e. what the ISP agrees to give you), and may be limited by other bottlenecks in the network or in your system. Scott.

Thanks Scott. Between your response here and the link to your "tip" post, you provided the *exact* information I was looking for.

I'm glad you got a technician who understood the situation after the lighting strike.

Evan