I use, aside of the working horse 2011 MBP, a older MacBook (early 2008) and had the same network trouble after a new Airport Extreme took over the wireless access point role at the time I got the MBPro.
The drop outs occur (in most cases) regardless of the used operating system (had Windows and Linux users too with the same) even as the actual discussions circle always around Lion.
If you take a look in the past along the threads here, you may notice, that the same discussions howl up every time a major OS X upgrade is rolled out.
My MBP is Model A1151. Not sure what year I got it, at least 3 years ago I suspect, making it around '08 or so. It was like-new off the Apple demo store site.
Side by side with a WinDoze (Dell) laptop, the Dell has absolutely NO problems with wireless, same location, same time, same router and WiFi channel, etc....etc.... Also, other WiFi devices no problem. So if it was something environmental, not specific to MBP, I wouldn't be doing the Forum Howl. Despite the oscillations about WiFi connectivity as new releases roll out, the problem as been ongoing for quite some time with MBP and nobody, as yet, has come up with any workable solution regardless of OS release since SL early.
That's a reason to think about two things:
- Interferences from other wireless in neighborhood or other 2.4GHz radio equipment; e.g. Bluetooth, wireless mouse/keyboard a.s.o. Even a leaking microwave may put you connection to the dump.
- Location of the router. It should not be placed directly on a wall, in a corner, on the floor, behind a furniture or on a place, where major obstacles (e.g. metal frames, high voltage lines) are in the way of the radio beam.
Which is why I bought the WAP and put it within 10 feet of where I am normally using the laptop downstairs. The WAP is 2.4g only, no 5g choice. If I could switch to 5g, maybe that would help. However, I don't know if or how to do that on the MBP even if the WAP supported it. BTW, I swapped the WiFi card out of the laptop about 4 months ago in attempt to fix this problem. Put in a new b,g,n capable card (original MBP only had b,g card). Did NOT make the problem better or worse, just stayed the same.
So now I am sitting within 5 ft. of the WAP, and I notice my connection speed is only 2 MBPS and the RSSI says -80. There is absolutely nothing between me and the WAP except air. No microwave on, no iPone nearby, no other WiFi devices within useful range. So what exactly am I to make of that? Oh, and the "bars" on the MBP status bar are "all on". ***? How is -80 and 2 MBS warrant "all bars"? This is precisely the sort of thing that leads one to the conclusion that the software is just plain stuck on stupid.
So yes, I agree that the problem MAY be related to interference some of the time, but not always (for instance at this precise moment I am writing this). But, nobody can just explain the behavior away as "interference", when other devices (non-MBP) work just fine in same location, at same time- that fact, as the lawyers say, speaks for itself.