the sort of the netcard...

i want to ask a question …
we install a SUSE os ,if we have three netcard,the default sort(eth0 eth1 eth2) of the netcard is define what rules ???
how the system sort the netcard ?
help ,help,…help…:’(

I would say it does in the sequence it detects them.

The renaming is done by udev. Check /etc/udev/rules.d/70-persistent-net.rules.