Problems with Gnet BB2060 DSL modem/router and routing static IP's

Hi:

My DSL provider sold me the above noted equipment as a modem and router
to connect my static subnet to their DSL service. The problem is, the
connection to a truly routed host drops out every 5 to 10 minutes for
about 20 seconds. I've played with it quite a bit, everything seems to
be set up correctly and the modem itself never loses it's connection
(for example, NAT'd hosts never drop their connection). I'm fairly
certain it's directly related to the routing hardware, which I must have
set up right since it works most of the time. For what it's worth, I've
upgraded to the latest firmware on the manufacturer's web site.

Anybody ever see a problem like this? Any help is appreciated. At this
point, I'm thinking of demoting it to just a modem and buying a Linksys
or other broadband router for the routing part (or maybe dedicating a
linux box to the task).

Thanks in advance.

p