Ok, I'm not familiar with the EtherWave product, but you described it as a "bridge". I have never seen a LocalTalk to Ethernet bridge that is capable of MacIP, but I guess it's possible that one exists. Usually, the MacIP feature is in routers, since bridges tend to be "dumb" devices. With the routers, you get configuration software so that you can define ranges of IP addresses to make available via MacIP. I don't know if this would apply to a MacIP capable bridge.

If the EtherWave is a bridge and connects to the Mac via LocalTalk, it shouldn't need a driver on the Mac. To confuse matters, there does appear to be an EtherWave branded ethernet adaptor that connects via the Mac Printer port, but uses its own, proprietary technique to communicate with the Mac for 3x LocalTalk speed. This would require a driver, would then appear as a second device in MacTCP, as Charlieman described and wouldn't need MacIP, since it would be an ethernet adaptor, not bridge or router. (Are you confused yet ???)

I use a device called an "EtherRoute TCP", which is a full blown AppleTalk bridge to get my old Macs on the Internet.