man/systemd.net-naming-scheme.xml

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   5
   6 <refentry id="systemd.net-naming-scheme">
   7   <refentryinfo>
   8     <title>systemd.net-naming-scheme</title>
   9     <productname>systemd</productname>
  10   </refentryinfo>
  11
  12   <refmeta>
  13     <refentrytitle>systemd.net-naming-scheme</refentrytitle>
  14     <manvolnum>7</manvolnum>
  15   </refmeta>
  16
  17   <refnamediv>
  18     <refname>systemd.net-naming-scheme</refname>
  19     <refpurpose>Network device naming schemes</refpurpose>
  20   </refnamediv>
  21
  22   <refsect1>
  23     <title>Description</title>
  24
  25     <para>Network interfaces names and MAC addresses may be generated based on certain stable interface
  26     attributes. This is possible when there is enough information about the device to generate those
  27     attributes and the use of this information is configured. This page describes interface naming, i.e. what
  28     possible names may be generated. Those names are generated by the
  29     <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
  30     builtin <command>net_id</command> and exported as udev properties
  31     (<varname>ID_NET_NAME_ONBOARD=</varname>, <varname>ID_NET_LABEL_ONBOARD=</varname>,
  32     <varname>ID_NET_NAME_PATH=</varname>, <varname>ID_NET_NAME_SLOT=</varname>).</para>
  33
  34     <para>Names and MAC addresses are derived from various stable device metadata attributes. Newer versions
  35     of udev take more of these attributes into account, improving (and thus possibly changing) the names and
  36     addresses used for the same devices. Different versions of those generation rules are called "naming
  37     schemes". The default naming scheme is chosen at compilation time. Usually this will be the latest
  38     implemented version, but it is also possible to set one of the older versions to preserve
  39     compatibility. This may be useful for example for distributions, which may introduce new versions of
  40     systemd in stable releases without changing the naming scheme. The naming scheme may also be overridden
  41     using the <varname>net.naming-scheme=</varname> kernel command line switch, see
  42     <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
  43     Available naming schemes are described below.</para>
  44
  45     <para>After the udev properties have been generated, appropriate udev rules may be used to actually rename
  46     devices based on those properties. See the description of <varname>NamePolicy=</varname> and
  47     <varname>MACAddressPolicy=</varname> in
  48     <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
  49
  50     <para>Note that while the concept of network interface naming schemes is primarily relevant in the
  51     context of <filename>systemd-udevd.service</filename>, the
  52     <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
  53     container manager also takes it into account when naming network interfaces, see below.</para>
  54   </refsect1>
  55
  56   <refsect1>
  57     <title>Naming</title>
  58
  59     <para>All names start with a two-character prefix that signifies the interface type.</para>
  60
  61     <table>
  62       <title>Two character prefixes based on the type of interface</title>
  63
  64       <tgroup cols='2'>
  65         <thead>
  66           <row>
  67             <entry>Prefix</entry>
  68             <entry>Description</entry>
  69           </row>
  70         </thead>
  71         <tbody>
  72           <row>
  73             <entry><constant>en</constant></entry>
  74             <entry>Ethernet</entry>
  75           </row>
  76           <row>
  77             <entry><constant>ib</constant></entry>
  78             <entry>InfiniBand</entry>
  79           </row>
  80           <row>
  81             <entry><constant>sl</constant></entry>
  82             <entry>Serial line IP (slip)</entry>
  83           </row>
  84           <row>
  85             <entry><constant>wl</constant></entry>
  86             <entry>Wireless local area network (WLAN)</entry>
  87           </row>
  88           <row>
  89             <entry><constant>ww</constant></entry>
  90             <entry>Wireless wide area network (WWAN)</entry>
  91           </row>
  92         </tbody>
  93       </tgroup>
  94     </table>
  95
  96     <para>The udev <command>net_id</command> builtin exports the following udev device properties:</para>
  97
  98     <variablelist>
  99         <varlistentry>
 100           <term><varname>ID_NET_NAME_ONBOARD=<replaceable>prefix</replaceable><constant>o</constant><replaceable>number</replaceable></varname></term>
 101
 102           <listitem><para>This name is set based on the numeric ordering information given by the firmware
 103           for on-board devices. The name consists of the prefix, letter <constant>o</constant>, and a number
 104           specified by the firmware. This is only available for PCI devices.</para>
 105           </listitem>
 106         </varlistentry>
 107
 108         <varlistentry>
 109           <term><varname>ID_NET_LABEL_ONBOARD=<replaceable>prefix</replaceable> <replaceable>label</replaceable></varname></term>
 110
 111           <listitem><para>This property is set based on textual label given by the firmware for on-board
 112           devices. The name consists of the prefix concatenated with the label. This is only available for
 113           PCI devices.
 114           </para>
 115           </listitem>
 116         </varlistentry>
 117
 118         <varlistentry>
 119           <term><varname>ID_NET_NAME_MAC=<replaceable>prefix</replaceable><constant>x</constant><replaceable>AABBCCDDEEFF</replaceable></varname></term>
 120
 121           <listitem><para>This name consists of the prefix, letter <constant>x</constant>, and 12 hexadecimal
 122           digits of the MAC address. It is available if the device has a fixed MAC address. Because this name
 123           is based on an attribute of the card itself, it remains "stable" when the device is moved (even
 124           between machines), but will change when the hardware is replaced.</para>
 125           </listitem>
 126         </varlistentry>
 127
 128         <varlistentry>
 129           <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]</varname></term>
 130           <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable><constant>v</constant><replaceable>slot</replaceable></varname></term>
 131           <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>b</constant><replaceable>number</replaceable></varname></term>
 132           <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>u</constant><replaceable>port</replaceable>…[<constant>c</constant><replaceable>config</replaceable>][<constant>i</constant><replaceable>interface</replaceable>]</varname></term>
 133           <term><varname>ID_NET_NAME_SLOT=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>v</constant><replaceable>slot</replaceable></varname></term>
 134
 135           <listitem><para>This property describes the slot position. Different schemes are used depending on
 136           the bus type, as described in the table below. In case of USB, BCMA, and SR-VIO devices, the full
 137           name consists of the prefix, PCI slot identifier, and USB or BCMA or SR-VIO slot identifier. The
 138           first two parts are denoted as "…" in the table below.</para>
 139
 140           <table>
 141             <title>Slot naming schemes</title>
 142
 143             <tgroup cols='2'>
 144               <thead>
 145                 <row>
 146                   <entry>Format</entry>
 147                   <entry>Description</entry>
 148                 </row>
 149               </thead>
 150
 151               <tbody>
 152                 <row>
 153                   <entry><replaceable>prefix</replaceable> [<constant>P</constant><replaceable>domain</replaceable>] <constant>s</constant><replaceable>slot</replaceable> [<constant>f</constant><replaceable>function</replaceable>] [<constant>n</constant><replaceable>port_name</replaceable> | <constant>d</constant><replaceable>dev_port</replaceable>]</entry>
 154                   <entry>PCI slot number</entry>
 155                 </row>
 156
 157                 <row>
 158                   <entry><replaceable>prefix</replaceable> <constant>v</constant><replaceable>slot</replaceable></entry>
 159                   <entry>VIO slot number (IBM PowerVM)</entry>
 160                 </row>
 161
 162                 <row>
 163                   <entry>… <constant>b</constant><replaceable>number</replaceable></entry>
 164                   <entry>Broadcom bus (BCMA) core number</entry>
 165                 </row>
 166
 167                 <row>
 168                   <entry>… <constant>u</constant><replaceable>port</replaceable>… [<constant>c</constant><replaceable>config</replaceable>] [<constant>i</constant><replaceable>interface</replaceable>]</entry>
 169                   <entry>USB port number chain</entry>
 170                 </row>
 171
 172                 <row>
 173                   <entry>… <constant>v</constant><replaceable>slot</replaceable></entry>
 174                   <entry>SR-VIO slot number</entry>
 175                 </row>
 176               </tbody>
 177             </tgroup>
 178           </table>
 179
 180           <para>The PCI domain is only prepended when it is not 0. All multi-function PCI devices will carry
 181           the <constant>f<replaceable>function</replaceable></constant> number in the device name, including
 182           the function 0 device. For non-multi-function devices, the number is suppressed if 0. The port name
 183           <replaceable>port_name</replaceable> is used, or the port number
 184           <constant>d</constant><replaceable>dev_port</replaceable> if the name is not known.</para>
 185
 186           <para>For BCMA devices, the core number is suppressed when 0.</para>
 187
 188           <para>For USB devices the full chain of port numbers of hubs is composed. If the name gets longer
 189           than the maximum number of 15 characters, the name is not exported. The usual USB configuration
 190           number 1 and interface number 0 values are suppressed.</para>
 191
 192           <para>SR-IOV virtual devices are named based on the name of the parent interface, with a suffix of
 193           <constant>v</constant> and the virtual device number, with any leading zeros removed. The bus
 194           number is ignored.</para>
 195
 196           <para>In some configurations a parent PCI bridge of a given network controller may be associated
 197           with a slot. In such case we don't generate this device property to avoid possible naming conflicts.</para>
 198           </listitem>
 199         </varlistentry>
 200
 201         <varlistentry>
 202           <term><varname>ID_NET_NAME_PATH=<replaceable>prefix</replaceable><constant>c</constant><replaceable>bus_id</replaceable></varname></term>
 203           <term><varname>ID_NET_NAME_PATH=<replaceable>prefix</replaceable><constant>a</constant><replaceable>vendor</replaceable><replaceable>model</replaceable><constant>i</constant><replaceable>instance</replaceable></varname></term>
 204           <term><varname>ID_NET_NAME_PATH=<replaceable>prefix</replaceable><constant>i</constant><replaceable>address</replaceable><constant>n</constant><replaceable>port_name</replaceable></varname></term>
 205           <term><varname>ID_NET_NAME_PATH=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>p</constant><replaceable>bus</replaceable><constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>phys_port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]</varname></term>
 206           <term><varname>ID_NET_NAME_PATH=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>p</constant><replaceable>bus</replaceable><constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>phys_port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>b</constant><replaceable>number</replaceable></varname></term>
 207           <term><varname>ID_NET_NAME_PATH=<replaceable>prefix</replaceable>[<constant>P</constant><replaceable>domain</replaceable>]<constant>p</constant><replaceable>bus</replaceable><constant>s</constant><replaceable>slot</replaceable>[<constant>f</constant><replaceable>function</replaceable>][<constant>n</constant><replaceable>phys_port_name</replaceable>|<constant>d</constant><replaceable>dev_port</replaceable>]<constant>u</constant><replaceable>port</replaceable>…[<constant>c</constant><replaceable>config</replaceable>][<constant>i</constant><replaceable>interface</replaceable>]</varname></term>
 208
 209           <listitem><para>This property describes the device installation location. Different schemes are
 210           used depending on the bus type, as described in the table below. For BCMA and USB devices, PCI path
 211           information must known, and the full name consists of the prefix, PCI slot identifier, and USB or
 212           BCMA location. The first two parts are denoted as "…" in the table below.</para>
 213
 214           <table>
 215             <title>Path naming schemes</title>
 216
 217             <tgroup cols='2'>
 218               <thead>
 219                 <row>
 220                   <entry>Format</entry>
 221                   <entry>Description</entry>
 222                 </row>
 223               </thead>
 224
 225               <tbody>
 226                 <row>
 227                   <entry><replaceable>prefix</replaceable> <constant>c</constant><replaceable>bus_id</replaceable></entry>
 228                   <entry>CCW or grouped CCW device identifier</entry>
 229                 </row>
 230
 231                 <row>
 232                   <entry><replaceable>prefix</replaceable> <constant>a</constant><replaceable>vendor</replaceable> <replaceable>model</replaceable> <constant>i</constant><replaceable>instance</replaceable></entry>
 233                   <entry>ACPI path names for ARM64 platform devices</entry>
 234                 </row>
 235
 236                 <row>
 237                   <entry><replaceable>prefix</replaceable> <constant>i</constant><replaceable>address</replaceable> <constant>n</constant><replaceable>port_name</replaceable></entry>
 238                   <entry>Netdevsim (simulated networking device) device number and port name</entry>
 239                 </row>
 240
 241                 <row>
 242                   <entry><replaceable>prefix</replaceable> [<constant>P</constant><replaceable>domain</replaceable>] <constant>p</constant><replaceable>bus</replaceable> <constant>s</constant><replaceable>slot</replaceable> [<constant>f</constant><replaceable>function</replaceable>] [<constant>n</constant><replaceable>phys_port_name</replaceable> | <constant>d</constant><replaceable>dev_port</replaceable>]</entry>
 243                   <entry>PCI geographical location</entry>
 244                 </row>
 245
 246                 <row>
 247                   <entry>… <constant>b</constant><replaceable>number</replaceable></entry>
 248                   <entry>Broadcom bus (BCMA) core number</entry>
 249                 </row>
 250
 251                 <row>
 252                   <entry>… <constant>u</constant><replaceable>port</replaceable>… [<constant>c</constant><replaceable>config</replaceable>] [<constant>i</constant><replaceable>interface</replaceable>]</entry>
 253                   <entry>USB port number chain</entry>
 254                 </row>
 255
 256               </tbody>
 257             </tgroup>
 258           </table>
 259
 260           <para>CCW and grouped CCW devices are found in IBM System Z mainframes. Any leading zeros and
 261           dots are suppressed.</para>
 262
 263           <para>For PCI, BCMA, and USB devices, the same rules as described above for slot naming are
 264           used.</para>
 265           </listitem>
 266         </varlistentry>
 267     </variablelist>
 268   </refsect1>
 269
 270   <refsect1>
 271     <title>History</title>
 272
 273     <para>The following "naming schemes" have been defined (which may be chosen at system boot-up time via
 274     the <varname>net.naming-scheme=</varname> kernel command line switch, see above):</para>
 275
 276     <variablelist>
 277         <varlistentry>
 278           <term><constant>v238</constant></term>
 279
 280           <listitem><para>This is the naming scheme that was implemented in systemd 238.</para></listitem>
 281         </varlistentry>
 282
 283         <varlistentry>
 284           <term><constant>v239</constant></term>
 285
 286           <listitem><para>Naming was changed for virtual network interfaces created with SR-IOV and NPAR and
 287           for devices where the PCI network controller device does not have a slot number associated.</para>
 288
 289           <para>SR-IOV virtual devices are named based on the name of the parent interface, with a suffix of
 290           <literal>v<replaceable>port</replaceable></literal>, where <replaceable>port</replaceable> is the
 291           virtual device number. Previously those virtual devices were named as if completely independent.
 292           </para>
 293
 294           <para>The ninth and later NPAR virtual devices are named following the scheme used for the first
 295           eight NPAR partitions. Previously those devices were not renamed and the kernel default
 296           ("eth<replaceable>N</replaceable>") was used.</para>
 297
 298           <para>Names are also generated for PCI devices where the PCI network controller device does not
 299           have an associated slot number itself, but one of its parents does. Previously those devices were
 300           not renamed and the kernel default was used.</para>
 301           </listitem>
 302         </varlistentry>
 303
 304         <varlistentry>
 305           <term><constant>v240</constant></term>
 306
 307           <listitem><para>The <literal>ib</literal> prefix and stable names for infiniband devices are
 308           introduced. Previously those devices were not renamed.</para>
 309
 310           <para>The ACPI index field (used in <varname>ID_NET_NAME_ONBOARD=</varname>) is now also used when
 311           0.</para>
 312
 313           <para>A new naming policy <varname>NamePolicy=keep</varname> was introduced. With this policy, if
 314           the network device name was already set by userspace, the device will not be renamed
 315           again. Previously, this naming policy applied implicitly, and now it must be explicitly
 316           requested. Effectively, this means that network devices will be renamed according to the
 317           configuration, even if they have been renamed already, if <constant>keep</constant> is not
 318           specified as the naming policy in the <filename index="false">.link</filename> file. See
 319           <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>
 320           for a description of <varname>NamePolicy=</varname>.</para></listitem>
 321         </varlistentry>
 322
 323         <varlistentry>
 324           <term><constant>v241</constant></term>
 325
 326           <listitem><para><option>MACAddressPolicy=persistent</option> was extended to set MAC addresses
 327           based on the device name. Previously addresses were only based on the
 328           <varname index="false">ID_NET_NAME_*</varname> attributes, which meant that interface names would
 329           never be generated for virtual devices. Now a persistent address will be generated for most
 330           devices, including in particular bridges.</para>
 331
 332           <para>Note: when userspace does not set a MAC address for a bridge device, the kernel will
 333           initially assign a random address, and then change it when the first device is enslaved to the
 334           bridge. With this naming policy change, bridges get a persistent MAC address based on the bridge
 335           name instead of the first enslaved device.</para></listitem>
 336         </varlistentry>
 337
 338         <varlistentry>
 339           <term><constant>v243</constant></term>
 340
 341           <listitem><para>Support for renaming netdevsim (simulated networking) devices was added. Previously
 342           those devices were not renamed.</para>
 343
 344           <para>Previously two-letter interface type prefix was prepended to
 345           <varname>ID_NET_LABEL_ONBOARD=</varname>. This is not done anymore.</para></listitem>
 346         </varlistentry>
 347
 348         <varlistentry>
 349           <term><constant>v245</constant></term>
 350
 351           <listitem><para>When
 352           <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 353           derives the name for the host side of the network interface created with
 354           <option>--network-veth</option> from the container name it previously simply truncated the result
 355           at 15 characters if longer (since that's the maximum length for network interface names). From now
 356           on, for any interface name that would be longer than 15 characters the last 4 characters are set to
 357           a 24bit hash value of the full interface name. This way network interface name collisions between
 358           multiple similarly named containers (who only differ in container name suffix) should be less
 359           likely (but still possible, since the 24bit hash value is very small).</para></listitem>
 360         </varlistentry>
 361
 362         <varlistentry>
 363           <term><constant>v247</constant></term>
 364
 365           <listitem><para>When a PCI slot is associated with a PCI bridge that has multiple child network
 366           controllers, the same value of the <varname>ID_NET_NAME_SLOT</varname> property might be derived
 367           for those controllers. This would cause a naming conflict if the property is selected as the device
 368           name. Now, we detect this situation and don't produce the <varname>ID_NET_NAME_SLOT</varname>
 369           property.</para></listitem>
 370         </varlistentry>
 371
 372       </variablelist>
 373
 374     <para>Note that <constant>latest</constant> may be used to denote the latest scheme known (to this
 375     particular version of systemd).</para>
 376   </refsect1>
 377
 378   <refsect1>
 379     <title>Examples</title>
 380
 381     <example>
 382       <title>Using <command>udevadm test-builtin</command> to display device properties</title>
 383
 384       <programlisting>$ udevadm test-builtin net_id /sys/class/net/enp0s31f6
 385 ...
 386 Using default interface naming scheme 'v243'.
 387 ID_NET_NAMING_SCHEME=v243
 388 ID_NET_NAME_MAC=enx54ee75cb1dc0
 389 ID_OUI_FROM_DATABASE=Wistron InfoComm(Kunshan)Co.,Ltd.
 390 ID_NET_NAME_PATH=enp0s31f6
 391 ...</programlisting>
 392     </example>
 393
 394     <example>
 395       <title>PCI Ethernet card with firmware index "1"</title>
 396
 397       <programlisting>ID_NET_NAME_ONBOARD=eno1
 398 ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
 399       </programlisting>
 400     </example>
 401
 402     <example>
 403       <title>PCI Ethernet card in hotplug slot with firmware index number</title>
 404
 405       <programlisting># /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
 406 ID_NET_NAME_MAC=enx000000000466
 407 ID_NET_NAME_PATH=enp5s0
 408 ID_NET_NAME_SLOT=ens1</programlisting>
 409     </example>
 410
 411     <example>
 412       <title>PCI Ethernet multi-function card with 2 ports</title>
 413
 414       <programlisting># /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
 415 ID_NET_NAME_MAC=enx78e7d1ea46da
 416 ID_NET_NAME_PATH=enp2s0f0
 417
 418 # /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
 419 ID_NET_NAME_MAC=enx78e7d1ea46dc
 420 ID_NET_NAME_PATH=enp2s0f1</programlisting>
 421     </example>
 422
 423     <example>
 424       <title>PCI WLAN card</title>
 425
 426       <programlisting># /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
 427 ID_NET_NAME_MAC=wlx0024d7e31130
 428 ID_NET_NAME_PATH=wlp3s0</programlisting>
 429     </example>
 430
 431     <example>
 432       <title>PCI IB host adapter with 2 ports</title>
 433
 434       <programlisting># /sys/devices/pci0000:00/0000:00:03.0/0000:15:00.0/net/ibp21s0f0
 435 ID_NET_NAME_PATH=ibp21s0f0
 436
 437 # /sys/devices/pci0000:00/0000:00:03.0/0000:15:00.1/net/ibp21s0f1
 438 ID_NET_NAME_PATH=ibp21s0f1</programlisting>
 439     </example>
 440
 441     <example>
 442       <title>USB built-in 3G modem</title>
 443
 444       <programlisting># /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
 445 ID_NET_NAME_MAC=wwx028037ec0200
 446 ID_NET_NAME_PATH=wwp0s29u1u4i6</programlisting>
 447     </example>
 448
 449     <example>
 450       <title>USB Android phone</title>
 451
 452       <programlisting># /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
 453 ID_NET_NAME_MAC=enxd626b3450fb5
 454 ID_NET_NAME_PATH=enp0s29u1u2</programlisting>
 455     </example>
 456
 457     <example>
 458       <title>s390 grouped CCW interface</title>
 459
 460       <programlisting># /sys/devices/css0/0.0.0007/0.0.f5f0/group_device/net/encf5f0
 461 ID_NET_NAME_MAC=enx026d3c00000a
 462 ID_NET_NAME_PATH=encf5f0</programlisting>
 463     </example>
 464   </refsect1>
 465
 466   <refsect1>
 467     <title>See Also</title>
 468     <para>
 469       <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
 470       <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
 471       <ulink url="https://systemd.io/PREDICTABLE_INTERFACE_NAMES">Predictable Network Interface Names</ulink>,
 472       <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
 473     </para>
 474   </refsect1>
 475
 476 </refentry>