I dunno about the first, but the second looks oddly reminiscent of when i had a N800 and the router at home didn't have a first clue about wifi power saving. I

I dunno about the first, but the second looks oddly reminiscent of when i had a N800 and the router at home didn't have a first clue about wifi power saving. IIRC how wifi does it is that the device signals the router and then shuts down the radio for some 100s of ms. This indicated to the router to hold the packets. Now if the router do not have a clue about the signal, it would likely treat the device as gone. So when it comes back on and expects to continue from where it left off, the router gets royally confused. Not sure why doing a dhcp request would fix it though, but then i have not the first clue about OSX innards.