A qeth device that connects to a virtual network on z/VM must be configured for the
same Open Systems Interconnection (OSI) layer as the virtual network. An ETHERNET
guest LAN or VSWITCH uses the data link layer (layer 2) while an IP guest LAN
or VSWITCH uses the network layer (layer 3).
User response
If you are connecting to an ETHERNET guest LAN or VSWITCH, set the layer2 sysfs
attribute of the qeth device to 1. If you are connecting to an IP guest LAN or
VSWITCH, set the layer2 sysfs attribute of the qeth device to 0.