Modem Upgrade

JerryDowning

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Jul 31, 2012
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I have a Linksys DOCSIS 2.0 modem and I am using the Comcast Performance tier. Comcast has been bugging me to upgrade my modem to DOCSIS 3.0. Every thing is working fine right now and I don't want to rock the boat. Is there anything to be gained by replacing my modem now or should I wait until it craps out.
 

osu1991

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Sep 4, 2004
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It depends on what speed that service level is and what you actually do online. I upgraded my Cox modem from a Motorola Surfboard 5100 series DOCSIS 2 to a 6100 series DOCSIS 3 and my upload is a lot more stable with the extra bonded channels in use. Downloads I don't know, I still get over 30meg down with both modems. I may have more consistent download speeds for multiple downloads with the new modem. I wouldn't have changed except I got the modem on sale for half price and was originally going to take it to our Vegas Condo until we found out we needed phone service for the security and entrance gates, so I decided to use it here at home
 

Voyager6

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Comcast will provide a DOCSIS 3 modem (with rental fee) to replace your DOCSIS 2 modem. If you buy your own, the rental fee goes away. The payback period is usually less than one year. If Comcast decides to increase the speeds in your area, you will need the DOCSIS 3 modem to get that speed increase.
 

navychop

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Yes. I am not too familiar with 2 vs 3 differences and cannot look it up right now but I suspect that moving to 3 will improve speeds and capacity for everyone on your neighborhood drop, simply due to greater efficiency.

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Voyager6

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Differences in DOCSIS 2 vs. DOCSIS 3 modems. http://www.speedguide.net/faq_in_q.php?qid=390
The main difference between DOCSIS 2 and DOCSIS 3 standard cable modems is that DOCSIS 3 allows for a much higher maximum throughput. DOCSIS 3.0 achieves that by using multi-channel bonding (using multiple channels simultaneously for download/upload) while DOCSIS 2 modems do not. A Docsis 3 modem with 4 bonded channels, for example would provide 4 times the bandwidth of a Docsis 2 modem.

Some other technical differences:
Docsis 3.0 supports QAM128 for upstream traffic, while many DOCSIS 2 support only QAM64
Docsis 3.0 specs use 108Mhz to 1.002Ghz downstream, 5Mhz to 85Mhz upstream.
Docsis 2.0 specs use 88Mhz to 860Mhz downstream, 5Mhz to 42Mhz upstream.

Changing to a DOCSIS 3 capable modem isn't going to change your maximum speed up, down or
sideways, only subscribing to an upgraded tier will. However, DOCSIS 3 has the ability to use multiple downstream and upstream channels at the same time (channel bonding) to maintain the maximum possible speed. Because of this, DOCSIS 3 may experience less of a speed drop during peak usage hours vs. a DOCSIS 2 modem. The D3 modem, depending on how new it is and how many channels the ISP makes available, has access to 2x-8x more bandwidth than a D2 modem, allowing for a somewhat more consistent connection.
 
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