If a computer has more than one network device with different drivers, it is possible for the interface designations to change after the boot process has completed if another driver has been loaded more quickly. For this reason, network devices in SUSE LINUX are administered via a queue. Alter this behavior by setting HOTPLUG_PCI_QUEUE_NIC_EVENTS=no in /etc/sysconfig/hotplug.
However, the best way to ensure consistent interface designations is to specify the desired name in the configuration files of the individual interfaces. Information about how to do this is contained in file /usr/share/doc/packages/sysconfig/README.