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25.3.3. Mapping Subchannels and Network Device Names

The DEVICE= option in the ifcfg file does not determine the mapping of subchannels to network device names. Instead, the udev rules file /etc/udev/rules.d/70-persistent-net.rules determines which network device channel gets which network device name.
When configuring a new network device on System z, the system automatically adds a new rule to that file and assigns the next unused device name. You can then edit the values assigned to the NAME= variable for each device.
Example content of /etc/udev/rules.d/70-persistent-net.rules:
# This file was automatically generated by the /lib/udev/write_net_rules
# program run by the persistent-net-generator.rules rules file.
#
# You can modify it,as long as you keep each rule on a single line.
# S/390 qeth device at 0.0.f5f0
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="qeth", KERNELS=="0.0.f5f0", ATTR{type}=="1", KERNEL=="eth*", NAME="eth0"
# S/390 ctcm device at 0.0.1000
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="ctcm", KERNELS=="0.0.1000", ATTR{type}=="256", KERNEL=="ctc*", NAME="ctc0"
# S/390 qeth device at 0.0.8024
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="qeth", KERNELS=="0.0.8024", ATTR{type}=="1", KERNEL=="hsi*", NAME="hsi0"
# S/390 qeth device at 0.0.8124
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="qeth", KERNELS=="0.0.8124", ATTR{type}=="1", KERNEL=="hsi*", NAME="hsi1"
# S/390 qeth device at 0.0.1017
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="qeth", KERNELS=="0.0.1017", ATTR{type}=="1", KERNEL=="eth*", NAME="eth3"
# S/390 qeth device at 0.0.8324
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="qeth", KERNELS=="0.0.8324", ATTR{type}=="1", KERNEL=="hsi*", NAME="hsi3"
# S/390 qeth device at 0.0.8224
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="qeth", KERNELS=="0.0.8224", ATTR{type}=="1", KERNEL=="hsi*", NAME="hsi2"
# S/390 qeth device at 0.0.1010
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="qeth", KERNELS=="0.0.1010", ATTR{type}=="1", KERNEL=="eth*", NAME="eth2"
# S/390 lcs device at 0.0.1240
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="lcs", KERNELS=="0.0.1240", ATTR{type}=="1", KERNEL=="eth*", NAME="eth1"
# S/390 qeth device at 0.0.1013
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="qeth", KERNELS=="0.0.1013", ATTR{type}=="1", KERNEL=="hsi*", NAME="hsi4"