cable modems

[Lori Kleinberg]

Anyone use or know anything about the Motorola wirless cable modem. My youngest just bought his 1st house. He only uses a laptop and wanted to hook it up wirelessly to the cable broadband. I believe he has 2 options; 1 regular cable modem hooked to the cable connection in the wall and then a wireless router for the laptop. Or a wireless cable modem hooked to the wall and then whatever.
Any suggestions ideas, etc?

[Andrew Derhammer]

I think best way may be a cable modem that feeds into a router. You made it seem like they have a regular pc also. The regular pc goes into this. Then pick up a wireless router(make sure it sends out the right signal for your card) and then wire that to the other router. This should allow expandability if they get another pc.

[Jeff Bratt]

A wireless cable modem is a cable modem plus wireless router in the same box. Separate boxes may or may not be more expensive, but that option is more flexible. Many wireless routers also have plugs for wired connections.

Once you have a router installed, you essentially have your own home network - then multiple computers can share the cable modem. With the cable modems it's pretty easy. Just make sure you (or someone who knows) enable adequate security settings for your wireless network...

[Steven Wilson]

I would use the wired cable modem recommended by your cable company and then plug that into a wireless broadband router. You will get better throughput wiring the laptop instead of going wireless. Anyhow, going with a wireless broadband router (has wireless and usually 4 wired ports) will let you attach NAS's, Voip adapters, and other cool things. I have one desktop connected wireless, a PS2 game console connected wireless, my desktop wired, my work laptop (wired or wireless), Vonage VoIP, Western Digital NetCenter, and a few other things attached. If my cable modem dies I have only one piece to replace and if my wireless router dies I can still attach my work PC directly to the cable modem and continue working.

[Mike Henderson]

What Steve Wilson said. The problem is that the technology of cable modems and WiFi type wireless changes at a different pace. So if they come out with a new and improved cable modem, you'll have to replace both. If they come out with a new and improved WiFi, you'll have to replace both.

If the wireless component fails in the combined box, you'll have to replace both.

It might be a bit more expensive (and bulky) to go with two boxes, but you get more flexability long term.

Mike

[Lori Kleinberg]

Thanks for the replies. Both he and his girlfriend have laptops that they currently use on a set up similar to what Andrew and Steve described. Can he still go with a regular cable modem even though it wouldn't be hooked up to a computer? He would just have the wireless router hooked to the modem and then use the laptop wirelessly (I hope this makes sense).

[Mike Henderson]

Thanks for the replies. Both he and his girlfriend have laptops that they currently use on a set up similar to what Andrew and Steve described. Can he still go with a regular cable modem even though it wouldn't be hooked up to a computer? He would just have the wireless router hooked to the modem and then use the laptop wirelessly (I hope this makes sense).

Yep, no problem (or at least none I can think of). Wireless is just another way to connect a computer - in other words, the wireless replaces the cable but everything else stays the same.

Mike

[Andrew Derhammer]

Thanks for the replies. Both he and his girlfriend have laptops that they currently use on a set up similar to what Andrew and Steve described. Can he still go with a regular cable modem even though it wouldn't be hooked up to a computer? He would just have the wireless router hooked to the modem and then use the laptop wirelessly (I hope this makes sense).

A regular modem should be fine. I just threw in the extra router because i was not sure if there was a pc that had to be run with internet or not. If not just hook the wireless router up to the modem directly.

[Jim Becker]

From a cost standpoint, buying a combined router/wireless access point is going to be the best choice, even if you don't use it as a router. APs without the router, for some reason, cost quite a bit more in most cases, probably because they don't sell a lot of them in the "home" space. But if the cable company just gives you the cable modem with no router, than the combined device will handle both the security and wireless functions.

Although I'm on DSL, the setup is the same as I'm describing. I happen to use an older Linksys router/wireless device just as a wireless access point behind a small Juniper router that's plugged into the DSL modem from Verizon. In fact, that's better for me as I can get the wireless AP where it does the most good in our house and that's not in the basement where my equipment rack is.

[Don Abele]

...You will get better throughput wiring the laptop instead of going wireless...

Steven, I have to disagree with you. I have cable which runs at 8 MB/s, my wireless LAN runs at 54 MB/s and wired LAN at 100 MB/s - the cable connection is the limiting factor here. The only thing you lose with wireless is computer to computer exchange speed.

Here is a speed comparison:

Wireless G: 54 MB/s
USB 2.0: 60 MB/s
LAN 100: 100 MB/s
HD ATA 133: 133 MB/s
HD SATA 150: 150 MB/s
HD SATA 300: 300 MB/s
Firewire 4: 400 MB/s
Firewire 8: 800 MB/s
LAN 1000: 1000 MB/s

Your speed is only as fast as the slowest component. Having a gigabit network with ATA-133 hard drives limits your transfer speed to 133 MB/s.


As for the OP's original question - I have run/maintained an extensive home network for over 8 years now. Currently I use a wireless G cable gateway by Linksys which gives me a cable modem, wireless access point, intranet hub, and router all in one. In the past I have had separate units for them all but they took up more space and more to configure to work together.

As for changing modems - the cable industry has been using the same standard for at least the past six years that I've had cable - I don't see them changing the protocol anytime soon.

And for changing wireless protocols - 802.11g has been the standard for many years and is what is common on laptops. The newest 802.11n is still in beta and not widely distributed on computers yet. To change a laptop from G (built-in) to N will require a PCMCIA or USB adapter card. So you can be pretty confident in buying a dedicated G wireless unit if that's what's on the laptops. Besides, N is backward compatible with G (and the much older B).

Be well,

Doc

[Lee DeRaud]

Currently I use a wireless G cable gateway by Linksys which gives me a cable modem, wireless access point, intranet hub, and router all in one. In the past I have had separate units for them all but they took up more space and more to configure to work together.

As for changing modems - the cable industry has been using the same standard for at least the past six years that I've had cable - I don't see them changing the protocol anytime soon.

The one "gotcha" in that is that most cable companies use the MAC address of the cable modem as the authentication key to get into their network: if that changes, you'll need to deal with their tech support to reconnect, which on average is dismal. (I know some modems allow you to set the MAC address manually but that's not universal.)

[Lori Kleinberg]

Wow, these responses are great. As usual Sawmill Creek has the best people.
So, any suggestions to type/brand modem or modem/router.

[Mike Henderson]

Don - I don't disagree with the general thrust of your posting but want to make a few points.

First, be careful to distinguish between bytes and bits. Ethernet is rated in bits rather than bytes. In the EE trade, we generally write a specification as 100 Mb/s for bits (small "b"), and 100 MB/s for bytes (cap "B").

Your specification for USB 2.0 is correct for bytes but it is normally specified as 480 Mb/s. I think serial ATA is normally specified in bytes for retail sale - I know it's a lot faster than 150 or 300 Mb/s.

WiFi is specified in bits. And 802.11n is quite a bit further along than beta. What's happened is that IEEE couldn't come to a final agreement (you have to attend some of those meetings to understand why) on 802.11n but the specification was essentially complete. The manufacturers took the pre-n specification and they have started volume shipping, testing against each other to make sure they interwork. While the IEEE may make noise about the spec not being agreed to, there's absolutely no way they're going to be able to make substantial changes to it (that will obsolete the stuff already shipped).

I would bet that the cable modem (with WiFi) doesn't come with anything more than g, and may even come with b. One day, the user may want to go to n, not for higher speed, but for the greater range that it offers. Having the wireless router as a separate device just makes it easier to upgrade.

Also, on cable modems, I haven't followed DOCIS that closely but there was work going on on advanced specifications. The cable companies are fairly slow to upgrade (it cost a lot of money) so the cable modem is not likely to upgrade anytime soon.

I enjoy your posts - they're always well thought out and make a lot of sense.

Mike

[I went and looked up the SATA spec. It is in bytes - 150 MB/s and 300 MB/s.]

[Steven Wilson]

Steven, I have to disagree with you. I have cable which runs at 8 MB/s, my wireless LAN runs at 54 MB/s and wired LAN at 100 MB/s - the cable connection is the limiting factor here. The only thing you lose with wireless is computer to computer exchange speed.

Throughput on your local network is what I'm talking about. If you connect your devices by wire to your router the speed is greater than if you have a wireless connection. Further a wired connection is more stable and is subject to less signal degredation than a wireless connection. The only connection problems I've experienced on my network are related to the wireless side, which is to be expected. Wireless is convienient, not better.

[Jim Becker]

Mike and Don, another factor is actual throughput. While your wireless connection might be synced up with your AP at 54 MB/s, the actual throughput may be lower depending on circumstances of the environment and other machines using the connection. With the exception of Meru's enterprise wireless products, for the most part, the 802.11 a/b/g/n technologies in use are a "shared" medium. This includes both consumer products like the typical Linksys, D-Link, Netgear, etc, stuff we put in our homes and the enterprise products from the big hitters. That said, if it's an 802.11g, 802.11a or 802.11n connection, in most cases the sync speed should still be at or above the cable or DSL connection capability. Then you have the issue of configuration "optimization" in the client adapter and OS. And many folks still are using older APs and wireless NICs that are only 802.11b capable or have an AP that defaults to the lower speed technology if even one device on the network is 802.11b only.

My point in all of this is that "connection speed" and "throughput" (the latter being actual performance) are not the same thing and we cannot assume that wireless performance will be equal to wired. Quite the contrary, although the new standards do afford the chance for getting much closer to parity.

Mike, I'm glad you brought up the cable modem "generation" point, too, although it's somewhat unrelated to the wireless question. The majority of cable modem service connections are still on the older DOCIS 2.0 or earlier technology and when that's combined with the huge number of homes that share the bandwidth on a typical cable service, actual throughput is way variable and rarely even close to the numbers that the provider uses to convince you that their service is "so fast" as compared to other options. Comcast, for example, just installed the new DOCIS 3.0 in the first two areas recently, according to a thread at BBR and the should help with performance, despite the fact that it doesn't eliminate the contention of major over-subscription due to the shared nature of the service.

Ultimately, I believe that Verizon has the right idea...fiber to the premise. Glass brings tremendous bandwidth capacity (important for the future of "content on demand" such as HD movies) and other advantages. There already have been pilots for 100MB/s to the home and in places like Korea, 50+ MB/s is almost standard. And the way that it's typically implemented from a design perspective, the "share point" moves closer to the core of the network, reducing local contention for bandwidth. (DSL already has that particular advantage over Cable, although being distance sensitive, the "achievable" top speed for DSL with most currently installed methods is lower)

'Gonna be interesting to see how this fleshes out as providers weigh the cost of transforming their networks and how that affects short term results on Wall Street versus leveraging technology to offer more and more options and opportunities for their customers to access...and buy...content with performance commensurate with the needs of that access to content.

{I was editing this for a long time due to a call coming in and see that Steven also mentions throughput...which is important to this discussion, despite my digression into technology}