docsis 3.0 cable modem + gateway - now earning its keep

My iPad was taking forever to load a web page. I tried a few sites and they were all slow. Later in the night, I used my Thinkpad laptop and the problem persisted. I have experienced wifi performance degradation at my house from time to time. Usually it will "cure" itself after a while. The degradation also tends to happen at one end of the house which suggest the likely direction of the offending interference(s).

Over the years I tried a lot of different things and some worked, albeit for a period of time, and eventually the intermittent degradation returns. The problem is not serious that leads to loss of critical tasks. I always have a PC that has a Ethernet connection.

For advance reading of causes of wifi interference, Cisco has an excellent white paper -  20 myths of wifi interference.

How I can tell when I have wifi interference problem as opposed to broadband speed problem from my ISP or the greater intercity, interstate network (there are many more entities to list here; e.g. the eyeballs to backbone hand off points)? I log into my wireless gateway via wifi. If the communication to the gateway is also slow, I know it is my wifi. If that is lightning fast, I then do a speedtest. This generally allow me to determine if the problem is LAN, or WAN.

Back to my problem. It was a wifi LAN problem. I reset the wireless LAN parameters and the problem disappeared. While I was at my PC with the Ethernet to my DOCSIS 3.0 cable modem with integral wireless gateway, I did a speed test. The result blew my socks off. The speed doubled the highest results that I normally get. I wanted to curb my enthusiasm in case the speed test is flaw. I want to sustain my joy until I can verify it is real.

I want to my 5k retina iMac and the result doubled the nominal result. Suspecting that my ISP may just increase the speed of my broadband tier, I googled online. Sure enough there was a not so well published news that Comcast is rolling out speed increase across Oregon.

Only a few weeks ago, I bought this Arris SBG6580 cable modem with integrated gateway from Amazon for half the normal price - because it is an open-box return. It is timely because with my old DOCSIS 2.0 modem and the separate D-Link gateway, both cannot achieve the new speed. The DOCSIS 2.0 modem uses only one cable's 6 MHz channel and is limited to about 30 Mbps bitrate (the actually rate can be a lot lower due to many reasons). My D-Link 802.11n gateway was one of the early model and it has many problems which limit the supposedly 802.11n performance. In the fastest configuration I could only achieve circa 20 Mbps.

here is docsis 2.0 with one channel of upstream and one channel of downstream

here is docsis 3.0 with up to 8 channels of downstream and 4 channels of upstream

Had I didn't acquire the Arris DOCSIS 3.0 I may not find out about the speed upgrade rolled out by Comcast in my area. So my new purchase was timely and one of the best deals of the year. Now my download speed is doubled. The upload speed remains the same as before.

here is my so called "performance" tier speed test result with the new 2x update - yes, Comcast hates informed consumers like me because i am an informed techie that want to keep this company as a provider of "internet dump pipe"

For long term, I am hoping Google gigabit fiber to roll out here in Portland. Portland was one of the cities that may be a part of the next roll out. I will dump Comcast (Xfinity) when that happens.