I have two old cable modems I used to use with my ISP, they are no longer used because I upgraded my service to include VOIP.

I was wondering what would be involved to create essentially a microcosm of the big cable companies DOCSIS networks, using the modems I have? This is just for experimentation/learning, I wouldn't connect them to my homes cable, I would be completely disconnected in order to avoid interfering with my cable company.

  • 2
    You would need to buy some expensive head-end equipment, nodes and fiber.
    – Ron Maupin
    Jul 18, 2016 at 15:17
  • @RonMaupin thanks, guess it's best to look to other projects
    – lightbord
    Jul 18, 2016 at 15:25
  • 2
    Modems don't talk to each other; they talk to a CMTS. There are "baby" CMTS's available, but any CMTS will be a highly complicated thing to setup and manage.
    – Ricky
    Jul 18, 2016 at 19:47
  • I was searching for "Can I use DOCSIS on my LAN instead of MoCA" and I couldn't find anything, so I started entering a question and then (as always) this question appeared on the right pane. I'm including my phrasing of the question as a comment for SEO. Related since you want to experiment: apparently you can get a couple of these for $20 and use that to turn a coax cable into an ethernet connection.
    – browly
    Aug 18, 2016 at 4:55
  • Did any answer help you? If so, you should accept the answer so that the question doesn't keep popping up forever, looking for an answer. Alternatively, you can post and accept your own answer.
    – Ron Maupin
    Jan 3, 2021 at 5:17

1 Answer 1


As already mentioned in comments - DOCSIS cable modems don't talk to each other, they need CMTS for communication & provisioning system to make them work.

If you are serious about playing with DOCSIS and have some money to invest in this you can build working lab these days relatively in-expensively.

  1. CMTS - search on Ebay or ask refurb hardware sellers, you are looking for something like Arris C3, Cisco uBR 7200-series (note it is not regular 7200, it must be uBR) or Motorola (BSR1000 or 2000, but I never used those).

  2. Provisioning system, which is used to:

    • issue DHCP leases to CMs & CPEs behind your CMs
    • generate and issue config file to CM
    • provide other services such is time sync
    • commercial ones have lots more bolted on top

You can build it from open source components. At the minimum you need DHCP, TFTP, ToD (Time of Day) and Syslog daemons and this software to create your DOCSIS config files. Alternatively you could ask one of the vendors for trial (time and/or number of CM limited).

You can find (not very up-to-date, but still partially valid) list of vendors on docsis.org

At last, but not least... DOCSIS is very popular and DOCSIS admins are very desired... just in case you don't know :)

Best of luck!

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