Your signal levels and signal to noise ratios for the cable feed are fine. They are a little high, but thats okay, as they will slowly drop over the next few years as the cable and connectors age. The most that I ever saw from my CGN3 on a 2.4 Ghz network is about 105 - 110 Mb/s. The 5 Ghz will top out around 200 Mb/s.
Just to check the wifi environment where you live you could install a program like inSSIDer. By looking at at, you, or we should be able to determine how tough it will be to see higher data rates. The link below is to the last freebie version of inSSIDer. It will monitor both 2.4 and 5 Ghz networks, but it does not display the newer 802.11ac networks which run in the 5 Ghz band. The network display will show both in list form and graphically, how many other routers are running nearby, and from the graphical display it is possible to determine if there are better channels to be operating on that might yield higher data rates. If your laptop is 5 Ghz capable, you should notice a significant difference in the number of 2.4 Ghz networks running versus the number of 5 Ghz networks running. That might give you some idea that the 5 Ghz band is a better place to be operating. If you load the application, take a screen shot of the network display and post it somewhere that we can have a look at it, we can tell you how easy or difficult it might be to switch channels.
http://www.techspot.com/downloads/5936-inssider.ht
Here is a link to the new version which has since become a pay version. For $20 U.S., if you run networks in the 5 Ghz band, its worth buying.
And that is why troubleshooting problems can be very difficult sometimes. These range from problems that come up over time, cabling and connectors deteriorating as they age, to problems with advanced settings, such as the one that you found. Its a pretty wide range to sort through. Good catch. I never would have thought of that at all. Definitely something to keep in the back of my mind during future troubleshooting sessions 🙂
We ran into some jumbo frames issues at work (and this is on HIGH END equipment, not stuff like the CGN3, etc).
Its quite possible that it doesnt support it at all.
The one issue we had at work was.. that it DID support jumbo frames.
BUT, not at the FULL values.
The packet headers, due to the network, etc... had a bigger packet, which was actually pusing it over the jumbo frame full size, causing an error.
Droping the size down to JUST under the full amount, making room for the header.. and its been fine.
Something like that COULD possibly work as well in these settings.
Though, unless you are running a server type machine, with a TON of I/O through it, i really dont think it would make a difference 🙂
