IP Address issues with cable modem

Every time that you change what is connected to a cable modem it MUST be turned off to make it forget the MAC address of the last device that was connected. If the cable modem is also a voice (phone) adapter it has an internal battery. Those have a reset switch on the back since removing the power doesn't turn them off.

I am unfamiliar with the Apple Extreme but if it supports 100 mbps or 1000 mbps LAN connections it will not affect your bandwidth. If it's really old and only supports 10 mbps, it's time to but a new modern one.

The Airport Extreme should offer a 54Mb/s connection (unless it's one of the very recent 'n' models) so it wouldn't reduce the internet speed - which is likely to be 16Mb/s not 16MB/s (bits not bytes).

kent909 wrote:
I just switched to Charter for my ISP. Did this to get their 16MB/sec

16 Mb/s. 16 MB/s is 16 megabytes/second, eight times as fast as your cableco will deliver.

download speed. When I first ran a speed test it came in at just over 8MB.

Try again, using a different server. Some servers are slower than others. I use speedtest.net for my speed testing, and I've found that the local server in my area (Ft Lauderdale, I'm in West Palm Beach) is consistently slow no matter which service I'm testing. The server in Atlanta, several hundred miles away, is much more reliable. The one in Miami, closer than Atlanta but further than Ft Lauderdale, is not as reliable as the Atlanta server but is more reliable than the Ft Lauderdale one.

The tech said that Apple Extremes degrades the bandwidth.

That is incorrect. The max speed your cableco says it delivers is 16 Mb/s. Wireless-G from a wireless router delivers 54 Mb/s at close range, wireless-n delivers 108 Mb/s. Wired connections are 100 to 1000 Mb/s.

He wanted to connect directly to the Mac from the cable modem to verify what speed I am actually getting. I cannot get an Internet connection connecting direct. A 169 ip address is assigned.

Your modem is not seeing the Mac. You need to restart it.

So two questions.

Is the tech correct about the Extreme reducing bandwidth?

No.

50%?
Any suggestions on how to get my Mac to acquire valid IP address when connecting direct?

Shut down the modem, wait 30 seconds, turn it back on. It'll see the Mac. (Note that if you want it to see the router you'll have to shut it down again before reconnecting the router.)

Thanks

The effective speed of just about any 802.11g WiFi base station is about half of the advertised rate. So a 54megabit/sec 802.11g speed in practice gives around 25'ish megabits/sec speeds. This is due to the protocol overhead.

But 25'ish megabits/sec is still faster than your cable modem's 16megabits/sec.

And yes it is always good to eliminate possible bottlenecks, so connecting directly to the cable modem via ethernet is a good test. And many cable modems lock into the first ethernet MAC address they see, so you most likely have to power cycle the cable modem before it will recognize your Mac. And when you switch back to your Airport Extreme base station another power cycle will most likely be necessary.

With respect to WiFi, there are other factors that can affect how fast you can transfer. Interference is the largest factor. Walls, especially ones with metal studs, or concrete (as in an high-rise condo building), or metal appliances directly between the base station and the Mac. Also Microwave ovens, 2.4GHz cordless phones (yours or neighbors), 2.4GHz baby monitors (your or neighbors), garage door openers. But the biggest interference source are WiFi base stations used by your neighbors. Especially if you are both using the same or adjacent channels.

Get a WiFi scanner, such as iStumbler, AP Grapher, KisMac, etc... and see what other WiFi base stations are in signal range, and what channels they are using. Your ideal setup is where the channel you use is 5 channels away from your strongest neighbor's signal. This is because each channel actually uses 5 channels worth of bandwidth. In the US, channels 1, 6, and 11 never overlap, and channel 6 is often the default channel. So your best bet is to use channel 1 or 11, assuming your neighbors have not camped on those channels already. If they have you need to find the largest 5 channel hole you can find and set you WiFi base station so it uses that channel.

If your neighborhood is over loaded with WiFi base stations, then see if you can switch to 802.11n 5GHz frequency. The current square Airport Extreme base stations support 5GHz 802.11n which has less traffic today, and the channels were setup with less overlap.

But first measure your download/upload speeds directly connecting to the cable modem, and then worry about interference from the neighbors.