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How to choose cable modem?

Discussion in 'Other Discussions' started by Budgeter, Oct 16, 2019.

  1. Budgeter

    Budgeter Occasional Visitor

    Joined:
    Dec 30, 2018
    Messages:
    18
    My friend is going to upgrade his system, and he's asking me for advice to do so. I have enough knowledge on router side, but for cable modem, there is nothing I can tell him.

    Can someone give me some shade light on this field for me?

    His plan is 60 Mbps (Comcast I believe), and I'm going to turn his cable modem into bridge mode. His current cable modem is https://wikidevi.com/wiki/Motorola_SURFboard_SBG6580
    As of now, there is some "preface" questions, but if there is something else I should know, please tell me.

    1) What specs/function should I look for?
    2) Do I even need docsis 3.1?
    3) Because it will work as bridge device only? Does it need to be powerful?
    4) Can a cable modem in anyway comparable to decent to hi-end router? (I believe it can't by any means)
     
  2. dosborne

    dosborne Senior Member

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    My experience with cable modems / routers is limited as I've only had one for 2 weeks, but the first question really is "Does the provider allow you to use your own?".

    Pretty sure I never had a choice. The rest of the questions may not matter if you must use ISP supplied equipment. What you install behind it is a different story.
     
    Budgeter likes this.
  3. RogerSC

    RogerSC Part of the Furniture

    Joined:
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    2,274
    Cable modems and routers are two very different things, no comparison. I would start with the list of compatible cable modems that his ISP provides, and look at the specs there. And I would go with a cable modem, not a combination cable modem and router. If you just get a cable modem, you don't need to put it in bridge mode. You only need to put the router part of a combined cable mode/router (called a "gateway") in bridge mode so that you can use your own router, a cable modem is always in "bridge mode" by definition, since it has no router in it. Just demodulates the cable signals into ethernet, no routing. There is definitely no point in buying a combined modem/router if you intend to use your own router anyways *smile*.

    DOCSIS 3.1 is nice, but again, if your ISP doesn't support it, and won't support it for some time, then you most likely don't need it. Unless you want to try to "future proof" your modem, since DOCSIS 3.1 will be coming at some point, like IPv6 *smile*. Some ISP's do support DOCSIS 3.1 now, from what I've heard.

    As far as what's important about a cable modem, you need to look at the speed that the modem supports. If you just buy a modem for your current speed tier, 60Mbps, that's not a great idea, since ISP's will occasionally raise their speed tiers, and you'll not be able to take advantage of that with a modem with low bandwidth. I'd personally be looking for a 16 bonded channel modem, which would be good up to at least 500Mbps, but you could also go with an 8 bonded channel modem, for about 300Mbps.

    I'm not aware of what to avoid, other than the Intel Puma chip set, which I heard was problematic a while ago. The chipset used in a modem is usually in the specifications, so you can check there.
     
    Budgeter likes this.
  4. gfondeur

    gfondeur New Around Here

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    Oct 4, 2019
    Messages:
    6
    I'm being using Zoom Telephonics cable modem for years, not complains at all, my current cable modem it's the 5370 I think that's the last one with the Zoom name on it, since the last few years they being branding the modems as a Motorola modem but it's the same thing, not complains at all with Zoom modems.
     
    Budgeter likes this.
  5. dosborne

    dosborne Senior Member

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    I would go with the router, not just the modem :)
    Completely disagree. :)

    I prefer to run my own router behind the ISP supplied device. Makes swapping their device in/out easier as nothing needs to change on the internal network. When necessary, I can enable WiFI on the ISP device so their tech can connect to performs tests etc and they don't need to be on my internal network. When the tech leaves, WiFi gets disabled. Should my router fail I can simply enable the basics on the other router until I get a replacement. Never hurts to have more capability as a backup.

    Setting up double NAT is simple.
     
    Budgeter likes this.
  6. Budgeter

    Budgeter Occasional Visitor

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    Dec 30, 2018
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    Is that why wikidevi doesn't put info of WI chip on multiple devices? I didn't aware there is also separate cable modem (non router device) so thanks for the information.

    Aside for compatibility issue, what else should I look for in router spec (kinda like truly recommended requirement).
    Just for E.g, maybe we don't need to apply them in reality.
    1) Docsis 3.1
    2) 32 x 8
    3) Broadcom cpu, 1 Ghz, Arm architect, 2 core, etc
    4) 512 mb ram from Samsung
    5) 128 mb flash
    6) ....................

    My friend's current router can be put in bridge mode, but it is really old and has inferior specs by now so I want to change it to. Besides, it constantly drops connection to ISP.
    I will change it for sure because connection issue (probably it is ISP-side problem too, but that's another story), but let say in case it still work perfectly, how will it compare to modern cable modem, which has better CPU, RAM, FLASH but other specs are the same?
     
  7. OzarkEdge

    OzarkEdge Very Senior Member

    Joined:
    Feb 14, 2018
    Messages:
    1,686
    Location:
    USA
    Determine the cable ISP's approved modem list... usually on their website, or ask them for it/link (beware stale lists). Use one of these modems that will support current and future service speeds. The trend is toward DOCSIS 3.1 and Gigabit service.

    Use your own router with i) the ISP's gateway in bridge mode or ii) the ISP's modem (no combination gateway modem/router) or iii) your own modem.

    If the ISP's box is not current, ask them for a new one. Or buy your own and provide its label details to their Tech Support to enable service.

    I've only ever used Arris modems and they have never failed me, so I like them. I currently use the SB6141... probably the value choice but still plenty fast. Otherwise, splurge for the SB8200. If you decide on a modem not on the ISP list, call their Tech Support to confirm that they can still provision it for their service (once you give them its label details).

    The same Arris modem can/may be sold in various channels in black or white and with slightly different model number prefixes (same suffix number)... it's a marketing thing. I favor the black version but have not shopped for them lately.

    Protect it with a UPS and it will be trouble-free.

    I would not dwell on cable modem specs... be thankful they are plug and play black boxes that just do their thing (except for combo gateways). If the existing ISP gateway in bridge mode yields acceptable speedtest.net results and is reliable, then use it. Otherwise, ask the ISP for a free upgrade to a modem only... or buy your own.

    When the router fails to connect to the Internet during setup, cycle power on the modem and wait.

    OE
     
    Last edited: Oct 17, 2019
    Budgeter and Marin like this.
  8. RMerlin

    RMerlin Super Moderator

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    But avoid anything based on an Intel Puma 6 chipset. Those are horribly buggy, adding a lot of bufferbloat to connections.

    Not sure if Puma 7 completely resolved these issues, but just to be safe, I'd look into something that's not Intel-based.