Hi,
Thank you for your reply.
Yes, I disabled DHCP on the DIR-615 as per the instructions. The DIR-615 is connected via cat-5 cable to my FiOS modem/router... LAN to LAN.
I did what you suggested and this is what I found when the internet connection is dropped:
I can't connect to the DIR-615 (by going to 192.168... etc)
I can't connect to the FiOS modem/router (by going to 192.168... etc)
I can't connect to my PC on the network, which is plugged directly into the FiOS modem/router
So it seems there is a problem between my Macbook and the DIR-615, not necessarily anything after the DIR-615.
If I go to the Airport thing at the upper-right corner of my Macbook screen and "Turn Airport Off", then "Turn Airport On", it reconnects to the DIR-615 and I can resume. That's what I've been doing since I bought the DIR-615. It's frustrating
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I'm going to try running the DIR-615 in n+g mixed mode and see if anything improves. In the meantime, is there something else I should look at?