1<?xml version='1.0'?>
2<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
3  "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
4<!-- SPDX-License-Identifier: LGPL-2.1-or-later -->
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>x</constant><replaceable>slot</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>b</constant><replaceable>number</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>u</constant><replaceable>port</replaceable>…[<constant>c</constant><replaceable>config</replaceable>][<constant>i</constant><replaceable>interface</replaceable>]</varname></term>
134          <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>
135
136          <listitem><para>This property describes the slot position. Different schemes are used depending on
137          the bus type, as described in the table below. In case of USB, BCMA, and SR-VIO devices, the full
138          name consists of the prefix, PCI slot identifier, and USB or BCMA or SR-VIO slot identifier. The
139          first two parts are denoted as "…" in the table below.</para>
140
141          <table>
142            <title>Slot naming schemes</title>
143
144            <tgroup cols='2'>
145              <thead>
146                <row>
147                  <entry>Format</entry>
148                  <entry>Description</entry>
149                </row>
150              </thead>
151
152              <tbody>
153                <row>
154                  <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>
155                  <entry>PCI slot number</entry>
156                </row>
157
158                <row>
159                  <entry><replaceable>prefix</replaceable> <constant>v</constant><replaceable>slot</replaceable></entry>
160                  <entry>VIO slot number (IBM PowerVM)</entry>
161                </row>
162
163                <row>
164                  <entry><replaceable>prefix</replaceable> <constant>X</constant><replaceable>number</replaceable></entry>
165                  <entry>VIF interface number (Xen)</entry>
166                </row>
167
168                <row>
169                  <entry>… <constant>b</constant><replaceable>number</replaceable></entry>
170                  <entry>Broadcom bus (BCMA) core number</entry>
171                </row>
172
173                <row>
174                  <entry>… <constant>u</constant><replaceable>port</replaceable>… [<constant>c</constant><replaceable>config</replaceable>] [<constant>i</constant><replaceable>interface</replaceable>]</entry>
175                  <entry>USB port number chain</entry>
176                </row>
177
178                <row>
179                  <entry>… <constant>v</constant><replaceable>slot</replaceable></entry>
180                  <entry>SR-VIO slot number</entry>
181                </row>
182              </tbody>
183            </tgroup>
184          </table>
185
186          <para>The PCI domain is only prepended when it is not 0. All multi-function PCI devices will carry
187          the <constant>f<replaceable>function</replaceable></constant> number in the device name, including
188          the function 0 device. For non-multi-function devices, the number is suppressed if 0. The port name
189          <replaceable>port_name</replaceable> is used, or the port number
190          <constant>d</constant><replaceable>dev_port</replaceable> if the name is not known.</para>
191
192          <para>For BCMA devices, the core number is suppressed when 0.</para>
193
194          <para>For USB devices the full chain of port numbers of hubs is composed. If the name gets longer
195          than the maximum number of 15 characters, the name is not exported. The usual USB configuration
196          number 1 and interface number 0 values are suppressed.</para>
197
198          <para>SR-IOV virtual devices are named based on the name of the parent interface, with a suffix of
199          <constant>v</constant> and the virtual device number, with any leading zeros removed. The bus
200          number is ignored.</para>
201
202          <para>In some configurations a parent PCI bridge of a given network controller may be associated
203          with a slot. In such case we don't generate this device property to avoid possible naming conflicts.</para>
204          </listitem>
205        </varlistentry>
206
207        <varlistentry>
208          <term><varname>ID_NET_NAME_PATH=<replaceable>prefix</replaceable><constant>c</constant><replaceable>bus_id</replaceable></varname></term>
209          <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>
210          <term><varname>ID_NET_NAME_PATH=<replaceable>prefix</replaceable><constant>i</constant><replaceable>address</replaceable><constant>n</constant><replaceable>port_name</replaceable></varname></term>
211          <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>
212          <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>
213          <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>
214
215          <listitem><para>This property describes the device installation location. Different schemes are
216          used depending on the bus type, as described in the table below. For BCMA and USB devices, PCI path
217          information must known, and the full name consists of the prefix, PCI slot identifier, and USB or
218          BCMA location. The first two parts are denoted as "…" in the table below.</para>
219
220          <table>
221            <title>Path naming schemes</title>
222
223            <tgroup cols='2'>
224              <thead>
225                <row>
226                  <entry>Format</entry>
227                  <entry>Description</entry>
228                </row>
229              </thead>
230
231              <tbody>
232                <row>
233                  <entry><replaceable>prefix</replaceable> <constant>c</constant><replaceable>bus_id</replaceable></entry>
234                  <entry>CCW or grouped CCW device identifier</entry>
235                </row>
236
237                <row>
238                  <entry><replaceable>prefix</replaceable> <constant>a</constant><replaceable>vendor</replaceable> <replaceable>model</replaceable> <constant>i</constant><replaceable>instance</replaceable></entry>
239                  <entry>ACPI path names for ARM64 platform devices</entry>
240                </row>
241
242                <row>
243                  <entry><replaceable>prefix</replaceable> <constant>i</constant><replaceable>address</replaceable> <constant>n</constant><replaceable>port_name</replaceable></entry>
244                  <entry>Netdevsim (simulated networking device) device number and port name</entry>
245                </row>
246
247                <row>
248                  <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>
249                  <entry>PCI geographical location</entry>
250                </row>
251
252                <row>
253                  <entry>… <constant>b</constant><replaceable>number</replaceable></entry>
254                  <entry>Broadcom bus (BCMA) core number</entry>
255                </row>
256
257                <row>
258                  <entry>… <constant>u</constant><replaceable>port</replaceable>… [<constant>c</constant><replaceable>config</replaceable>] [<constant>i</constant><replaceable>interface</replaceable>]</entry>
259                  <entry>USB port number chain</entry>
260                </row>
261
262              </tbody>
263            </tgroup>
264          </table>
265
266          <para>CCW and grouped CCW devices are found in IBM System Z mainframes. Any leading zeros and
267          dots are suppressed.</para>
268
269          <para>For PCI, BCMA, and USB devices, the same rules as described above for slot naming are
270          used.</para>
271          </listitem>
272        </varlistentry>
273    </variablelist>
274  </refsect1>
275
276  <refsect1>
277    <title>History</title>
278
279    <para>The following "naming schemes" have been defined (which may be chosen at system boot-up time via
280    the <varname>net.naming-scheme=</varname> kernel command line switch, see above):</para>
281
282    <variablelist>
283        <varlistentry>
284          <term><constant>v238</constant></term>
285
286          <listitem><para>This is the naming scheme that was implemented in systemd 238.</para></listitem>
287        </varlistentry>
288
289        <varlistentry>
290          <term><constant>v239</constant></term>
291
292          <listitem><para>Naming was changed for virtual network interfaces created with SR-IOV and NPAR and
293          for devices where the PCI network controller device does not have a slot number associated.</para>
294
295          <para>SR-IOV virtual devices are named based on the name of the parent interface, with a suffix of
296          <literal>v<replaceable>port</replaceable></literal>, where <replaceable>port</replaceable> is the
297          virtual device number. Previously those virtual devices were named as if completely independent.
298          </para>
299
300          <para>The ninth and later NPAR virtual devices are named following the scheme used for the first
301          eight NPAR partitions. Previously those devices were not renamed and the kernel default
302          ("eth<replaceable>N</replaceable>") was used.</para>
303
304          <para>Names are also generated for PCI devices where the PCI network controller device does not
305          have an associated slot number itself, but one of its parents does. Previously those devices were
306          not renamed and the kernel default was used.</para>
307          </listitem>
308        </varlistentry>
309
310        <varlistentry>
311          <term><constant>v240</constant></term>
312
313          <listitem><para>The <literal>ib</literal> prefix and stable names for infiniband devices are
314          introduced. Previously those devices were not renamed.</para>
315
316          <para>The ACPI index field (used in <varname>ID_NET_NAME_ONBOARD=</varname>) is now also used when
317          0.</para>
318
319          <para>A new naming policy <varname>NamePolicy=keep</varname> was introduced. With this policy, if
320          the network device name was already set by userspace, the device will not be renamed
321          again. Previously, this naming policy applied implicitly, and now it must be explicitly
322          requested. Effectively, this means that network devices will be renamed according to the
323          configuration, even if they have been renamed already, if <constant>keep</constant> is not
324          specified as the naming policy in the <filename index="false">.link</filename> file. See
325          <citerefentry><refentrytitle>systemd.link</refentrytitle><manvolnum>5</manvolnum></citerefentry>
326          for a description of <varname>NamePolicy=</varname>.</para></listitem>
327        </varlistentry>
328
329        <varlistentry>
330          <term><constant>v241</constant></term>
331
332          <listitem><para><option>MACAddressPolicy=persistent</option> was extended to set MAC addresses
333          based on the device name. Previously addresses were only based on the
334          <varname index="false">ID_NET_NAME_*</varname> attributes, which meant that interface names would
335          never be generated for virtual devices. Now a persistent address will be generated for most
336          devices, including in particular bridges.</para>
337
338          <para>Note: when userspace does not set a MAC address for a bridge device, the kernel will
339          initially assign a random address, and then change it when the first device is enslaved to the
340          bridge. With this naming policy change, bridges get a persistent MAC address based on the bridge
341          name instead of the first enslaved device.</para></listitem>
342        </varlistentry>
343
344        <varlistentry>
345          <term><constant>v243</constant></term>
346
347          <listitem><para>Support for renaming netdevsim (simulated networking) devices was added. Previously
348          those devices were not renamed.</para>
349
350          <para>Previously two-letter interface type prefix was prepended to
351          <varname>ID_NET_LABEL_ONBOARD=</varname>. This is not done anymore.</para></listitem>
352        </varlistentry>
353
354        <varlistentry>
355          <term><constant>v245</constant></term>
356
357          <listitem><para>When
358          <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
359          derives the name for the host side of the network interface created with
360          <option>--network-veth</option> from the container name it previously simply truncated the result
361          at 15 characters if longer (since that's the maximum length for network interface names). From now
362          on, for any interface name that would be longer than 15 characters the last 4 characters are set to
363          a 24bit hash value of the full interface name. This way network interface name collisions between
364          multiple similarly named containers (who only differ in container name suffix) should be less
365          likely (but still possible, since the 24bit hash value is very small).</para></listitem>
366        </varlistentry>
367
368        <varlistentry>
369          <term><constant>v247</constant></term>
370
371          <listitem><para>When a PCI slot is associated with a PCI bridge that has multiple child network
372          controllers, the same value of the <varname>ID_NET_NAME_SLOT</varname> property might be derived
373          for those controllers. This would cause a naming conflict if the property is selected as the device
374          name. Now, we detect this situation and don't produce the <varname>ID_NET_NAME_SLOT</varname>
375          property.</para></listitem>
376        </varlistentry>
377
378        <varlistentry>
379          <term><constant>v249</constant></term>
380
381          <listitem><para>PCI hotplug slot names for the s390 PCI driver are a hexadecimal representation
382          of the <filename>function_id</filename> device attribute. This attribute is now used to build the
383          <varname>ID_NET_NAME_SLOT</varname>. Before that, all slot names were parsed as decimal
384          numbers, which could either result in an incorrect value of the <varname>ID_NET_NAME_SLOT</varname>
385          property or none at all.</para>
386
387          <para>Some firmware and hypervisor implementations report unreasonably high numbers for the onboard
388          index. To prevent the generation of bogus onbard interface names, index numbers greater than 16381
389          (2¹⁴-1) were ignored. For s390 PCI devices index values up to 65535 (2¹⁶-1) are valid. To account
390          for that, the limit was increased to 65535.</para>
391
392          <para>The udev rule <varname>NAME=</varname> replaces <literal>:</literal>,
393          <literal>/</literal>, and <literal>%</literal> with an underscore (<literal>_</literal>), and
394          refuses strings which contain only numerics.</para>
395          </listitem>
396        </varlistentry>
397
398        <varlistentry>
399          <term><constant>v250</constant></term>
400
401          <listitem><para>Added naming scheme for Xen netfront "vif" interfaces based on the guest side
402          VIF number set from the Xen config (or the interface index in AWS EC2).</para>
403          </listitem>
404        </varlistentry>
405
406        <varlistentry>
407          <term><constant>v251</constant></term>
408
409          <listitem><para>Since version <constant>v247</constant> we no longer set
410          <varname>ID_NET_NAME_SLOT</varname> if we detect that a PCI device associated with a slot is a PCI
411          bridge as that would create naming conflict when there are more child devices on that bridge. Now,
412          this is relaxed and we will use slot information to generate the name based on it but only if
413          the PCI device has multiple functions. This is safe because distinct function number is a part of
414          the device name for multifunction devices.</para>
415          </listitem>
416        </varlistentry>
417
418      </variablelist>
419
420    <para>Note that <constant>latest</constant> may be used to denote the latest scheme known (to this
421    particular version of systemd).</para>
422  </refsect1>
423
424  <refsect1>
425    <title>Examples</title>
426
427    <example>
428      <title>Using <command>udevadm test-builtin</command> to display device properties</title>
429
430      <programlisting>$ udevadm test-builtin net_id /sys/class/net/enp0s31f6
431...
432Using default interface naming scheme 'v243'.
433ID_NET_NAMING_SCHEME=v243
434ID_NET_NAME_MAC=enx54ee75cb1dc0
435ID_OUI_FROM_DATABASE=Wistron InfoComm(Kunshan)Co.,Ltd.
436ID_NET_NAME_PATH=enp0s31f6
437...</programlisting>
438    </example>
439
440    <example>
441      <title>PCI Ethernet card with firmware index "1"</title>
442
443      <programlisting>ID_NET_NAME_ONBOARD=eno1
444ID_NET_NAME_ONBOARD_LABEL=Ethernet Port 1
445      </programlisting>
446    </example>
447
448    <example>
449      <title>PCI Ethernet card in hotplug slot with firmware index number</title>
450
451      <programlisting># /sys/devices/pci0000:00/0000:00:1c.3/0000:05:00.0/net/ens1
452ID_NET_NAME_MAC=enx000000000466
453ID_NET_NAME_PATH=enp5s0
454ID_NET_NAME_SLOT=ens1</programlisting>
455    </example>
456
457    <example>
458      <title>PCI Ethernet multi-function card with 2 ports</title>
459
460      <programlisting># /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.0/net/enp2s0f0
461ID_NET_NAME_MAC=enx78e7d1ea46da
462ID_NET_NAME_PATH=enp2s0f0
463
464# /sys/devices/pci0000:00/0000:00:1c.0/0000:02:00.1/net/enp2s0f1
465ID_NET_NAME_MAC=enx78e7d1ea46dc
466ID_NET_NAME_PATH=enp2s0f1</programlisting>
467    </example>
468
469    <example>
470      <title>PCI WLAN card</title>
471
472      <programlisting># /sys/devices/pci0000:00/0000:00:1c.1/0000:03:00.0/net/wlp3s0
473ID_NET_NAME_MAC=wlx0024d7e31130
474ID_NET_NAME_PATH=wlp3s0</programlisting>
475    </example>
476
477    <example>
478      <title>PCI IB host adapter with 2 ports</title>
479
480      <programlisting># /sys/devices/pci0000:00/0000:00:03.0/0000:15:00.0/net/ibp21s0f0
481ID_NET_NAME_PATH=ibp21s0f0
482
483# /sys/devices/pci0000:00/0000:00:03.0/0000:15:00.1/net/ibp21s0f1
484ID_NET_NAME_PATH=ibp21s0f1</programlisting>
485    </example>
486
487    <example>
488      <title>USB built-in 3G modem</title>
489
490      <programlisting># /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.4/2-1.4:1.6/net/wwp0s29u1u4i6
491ID_NET_NAME_MAC=wwx028037ec0200
492ID_NET_NAME_PATH=wwp0s29u1u4i6</programlisting>
493    </example>
494
495    <example>
496      <title>USB Android phone</title>
497
498      <programlisting># /sys/devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/net/enp0s29u1u2
499ID_NET_NAME_MAC=enxd626b3450fb5
500ID_NET_NAME_PATH=enp0s29u1u2</programlisting>
501    </example>
502
503    <example>
504      <title>s390 grouped CCW interface</title>
505
506      <programlisting># /sys/devices/css0/0.0.0007/0.0.f5f0/group_device/net/encf5f0
507ID_NET_NAME_MAC=enx026d3c00000a
508ID_NET_NAME_PATH=encf5f0</programlisting>
509    </example>
510  </refsect1>
511
512  <refsect1>
513    <title>See Also</title>
514    <para>
515      <citerefentry><refentrytitle>udev</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
516      <citerefentry><refentrytitle>udevadm</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
517      <ulink url="https://systemd.io/PREDICTABLE_INTERFACE_NAMES">Predictable Network Interface Names</ulink>,
518      <citerefentry><refentrytitle>systemd-nspawn</refentrytitle><manvolnum>1</manvolnum></citerefentry>
519    </para>
520  </refsect1>
521
522</refentry>
523