cable modem-wifi combination or not?

Hi, I'm going to switch from ADSL to T-W cable (the only option in my building). I've got an Airport Extreme on my TimeCapsule (this is the 500GB drive version), which I use with my laptop. The iMac is hardwired to the router. I was looking around at Best Buy where they sell T-W "approved" networking gear. The cable modems all seem to be modem + WiFi router combination units at various price points between about $80-200. My question is this: does it matter what kind of hardware I use as long as it's T-W compatible/approved. Any thoughts on the combination units or is a cable modem + my Airport Extreme the way to go. Not sure of the speed yet, but it's unlikely I'll contract for anything more than 50 Mbps and possibly even 15 Mbps. Some of the Motorola units I was looking at support very high bitrates but they use channel bonding to achieve that. I read somewhere that if you buy the combination units, you can't update the firmware, but that doesn't make sense to me.

iMac (21.5-inch, Late 2013), OS X Mavericks (10.9.4)

Posted on Sep 12, 2016 3:57 PM

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11 replies

Sep 12, 2016 4:17 PM in response to ArbeeNYC

Ask TW for a modem without built-in router. Then run an Ethernet cable from the modem's Ethernet port to the WAN port on your AEBS. You can connect your computers to the router either wired or wirelessly. This is the best configuration.


If you have no need for Ethernet, then you can use a cable modem with Wi-Fi router just as well. The main drawback is the difficulty you may have trying to extend the modem/router using Apple hardware.

Sep 12, 2016 4:27 PM in response to Kappy

I should add that my present setup uses the AEBS only for WiFi, it's connected in bridge mode to a Linksys router (which I'll get rid of once the cable is installed). My iMac is connected by Ethernet cable to the Linksys. I also want to connect the iMac using an Ethernet cable when I switch to cable. (Also, the cable modem/WiFi router unit I was looking at has four Ethernet ports on it. Most of them have at least 2 ports.)

Sep 13, 2016 8:15 AM in response to ArbeeNYC

If you use a modem/router then in addition to generating Wi-Fi connections it must also be able to connect to your computer or a second router using Ethernet. In that way you can use your existing setup much the same with the cable modem/router acting like your LinkSys. The AEBS would connect also in Bridge Mode.


You should inform the service person from TW while they are installing your new equipment just how you expect to use your AEBS. Personally, I would opt for a plain cable modem without any built-in router or any kind so you can use the AEBS as it should be used - both for Wi-Fi and Ethernet. But this will depend on what sort of hardware the cable company can supply.

Sep 13, 2016 8:23 AM in response to Kappy

Well, almost all the modem/routers I looked at have at least 2 Ethernet ports. The Motorola unit has four of them, so no problem there. However, if I use the new modem/router like the Linksys, why bother with a WiFi router at all. The only advantage (well, one of them) is that the new unit supports the new WiFi protocols that the AEBS does not. I'm using this in an apartment. It's not that large, and the longest run is about 30 ft. Right now, I can get coverage with the AEBS and my dinky 1.5 Mbps DSL service. However, if I'm paying T-W cable for 15 or 50 Mbps of service, I'd like to be able to broadcast that via WiFi to the other end of the apartment. If the AEBS can do that (and it should be able to), that's fine. It's hard to read through all the marketing hoopla that comes with these devices to figure out what you need.


By the way, I've always wondered how T-W configures its cable modems when there is no router between the modem and the computer. I have friends who use it that way - iMac plugged directly into cable modem and no router in between. Is there no NAT going on between the two units in that case? I haven't checked recently, but when I last looked, it appeared to be an unroutable IP address that my friend was getting.


Also, if I use the AEBS as my main router, any idea how to configure it? It's not going to be in bridge mode any longer and I'm unfamiliar with cable. Or should the tech know that?

Sep 14, 2016 8:24 AM in response to ArbeeNYC

If the Motorola modem/router has four Ethernet ports plus wireless, then you would have no need of the AEBS other than to extend a wireless network, but Apple routers do not play nice with non-Apple network devices.


The modems do not need a connection to a router for configuration. They establish a wireless connection and have a router built-in. However, if only one device will connect to the modem, then you can run an Ethernet line from the modem directly to the computer. The downside of this is you are now connected directly to the Internet. You have zero security between you and every other person on the Internet. That's not good. Better to have a hardware router between the computer and the modem because then you can be protected by NAT and the router's built-in security and an active firewall. Hence, why you need to enable WPA security when you hook up your devices/computers.


The AEBS is configured using Airport Utility that is located in the Utilities folder. Most cable supplied routers are configured through your browser. The actual model is configured through your cable connection along with a telephone call from the installer technician and the cable company's tech support.

Sep 14, 2016 8:31 AM in response to Kappy

"but Apple routers do not play nice with non-Apple network devices."


Hmm. So, connecting the router to a plain cable modem is a bad idea? There's no other way to do it other than replacing the AEBS with a non-Apple router, which seems a shame.


"However, if only one device will connect to the modem, then you can run an Ethernet line from the modem directly to the computer. The downside of this is you are now connected directly to the Internet."


This is what I've always wondered about since most people simply connect their cable modem directly to their computers. What you're saying is that there's no NAT going on in the cable modem and I'm getting a routable address (which I don't want) on the internal network. Also, WPA is a wireless protocol if I'm not mistaken, is it not?


I've configured the AEBS before. It's currently set up in bridge mode since it's connected to a Linksys router, which is doing the NAT and the AEBS doesn't like double-NAT arrangements. Also, I was told that T-W cable will only ensure that you have a WAN connection up to the cable modem's Ethernet port. Beyond that it's your responsibility. That is, they are not going to configure the AEBS or any other device found downstream of the cable modem.


As an aside, I read that the WiFi on combo cable modem/routers is terrible. Have you heard of this?

Thanks for the feedback.

Sep 14, 2016 12:47 PM in response to ArbeeNYC

No, you misunderstood or i was not very clear. Connecting to a plain modem is fine with an AEBS. But an Apple router cannot extend a wireless connection except in Bridge Mode. I use my AEBS connected directly to the single Ethernet line on my cable modem here. That was what I meant. At my other residence I have a modem/router provided by my cable company. It had four Ethernet ports and wireless, so I just removed the AEBS and used it instead. But there I do not use an AEX to extend the wireless. I use a non-Apple repeater.


If you connect a computer directly to the Ethernet port of a modem (no router involved in the modem or otherwise) then your IP will be a public IP assigned to the cable modem by the cable company. This IP can be hacked. However, once you connect a router between the modem and the computer (wired or wireless) then your computer's IP is a local one that cannot be directly hacked via the Internet. The NAT provides one level of protection. WPA is a security protocol used for the wireless network if you have one. It provides a level of protection that helps prevent someone from directly hacking into the wireless network created by the router.


Cable installers are usually not permitted to do any local configuration other than for their installed device. An AEBS or AEX or any other routing device that you provide is not their responsibility.


So, my advice is this. If the cable company is installing a modem/router device that provides both local wireless and has four Ethernet LAN ports, then disconnect the AEBS and do not use it. If you need to extend the wireless have the cable company provide their own solution or buy a non-Apple access point (repeater) such as you can get from D-Link, etc. I use D-Link devices, but there are many others that will do the job. If you ask the installer they may even give you a recommendation.

Sep 14, 2016 3:27 PM in response to Kappy

Oh, OK. Got it. Was just wondering. My apartment isn't that big, so the WiFi doesn't need to travel more than 30 feet, max, which should be within reach of the AEBS.


Thanks for confirming what I suspected, that a computer connected directly to the modem will have a routable IP address.


I guess my question now is how should the AEBS be setup? I know how to set up my current Linksys router for my ADSL setup, I use PPPoE. But I've never had a cable setup before so am unclear about how to configure the AEBS. Should be pretty basic, but I'd like to have an idea before I start messing around with it. It's currently in bridge mode and connected to my Linksys, which is doing the NAT. Right now, the AEBS simply provides wireless to my old Macbook Air, iPod, iPhone, etc. Appreciate the advice and the info. With T-W cable, I can purchase my own hardware. Using theirs incurs a roughly $10/month fee.

Sep 14, 2016 3:55 PM in response to ArbeeNYC

If you also don't use their modem, then buy a Motorola cable modem. I use an older Motorola 5120 that does not have any built-in router. It has one Ethernet WAN port that is connected to the WAN port on my AEBS. There isn't very much configuration needed, and it is all done using Airpot Utility.


However, if you use your own modem, then best have it available when the installer is present because the modem will require provisioning in order to work on the TW network. This is one reason for trying to arrange using a modem from the cable company. As far as I know they don't usually charge extra for it. But I don't know how this will work in your area. You can also continue using the LinkSys router if you want. It does all the same stuff as the AEBS does.

Sep 14, 2016 4:07 PM in response to Kappy

OK. Point noted. Been looking at a Motorola model, in fact. You're right, I could use the Linksys, although it's not exactly new. I've had it for a bunch of years. One of those old blue and black models with four ports on the back. Was a very popular model way back when (it's an SR41). Believe the ports are 10/100, so it should support 50 Mbps. However, the Airport is a lot newer. Thanks again.

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cable modem-wifi combination or not?

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