Android has state tracker (the connection management) for both mobile connections and wifi connections. But it does not support ethernet devices.
This is not an issue for a phone , but it causes following issues with netbook:
1. you can not manage your ethernet device from UI at all
2. With current way of enabling ethernet device (netcfg eth0 dhcp). If you unplug/plug cable, you will not have your dhcp ip address reset
3. ethernet device can not report connectivity changes correctly
Now, I'm working on the ethernet state tracker support for Android-x86. This blog thread is created to track this work.