CINXE.COM

<!DOCTYPE html> <html> <head> <meta charset="UTF-8"/> <meta name="viewport" content="width=device-width, initial-scale=1.0"> <link rel="stylesheet" href="/mandoc.css" type="text/css" media="all"> <title>ifmedia(4) - OpenBSD manual pages</title> </head> <body> <header> <section> <h1><a href="https://www.openbsd.org/">OpenBSD</a> manual page server</h1> </section> <form role="search" action="/" method="get" autocomplete="off" autocapitalize="none"> <fieldset> <legend>Manual Page Search Parameters</legend> <label>Search query: <input type="search" name="query" value="ifmedia" size="40"> </label> <button type="submit" name="apropos" value="0">man</button> <button type="submit" name="apropos" value="1">apropos</button> <br/> <select name="sec" aria-label="Manual section"> <option value="0">All Sections</option> <option value="1">1 - General Commands</option> <option value="2">2 - System Calls</option> <option value="3">3 - Library Functions</option> <option value="3p">3p - Perl Library</option> <option value="4" selected="selected">4 - Device Drivers</option> <option value="5">5 - File Formats</option> <option value="6">6 - Games</option> <option value="7">7 - Miscellaneous Information</option> <option value="8">8 - System Manager's Manual</option> <option value="9">9 - Kernel Developer's Manual</option> </select> <select name="arch" aria-label="CPU architecture"> <option value="default" selected="selected">All Architectures</option> <option>amd64</option> <option>alpha</option> <option>armv7</option> <option>arm64</option> <option>hppa</option> <option>i386</option> <option>landisk</option> <option>loongson</option> <option>luna88k</option> <option>macppc</option> <option>mips64</option> <option>octeon</option> <option>powerpc64</option> <option>riscv64</option> <option>sparc64</option> <option>amiga</option> <option>arc</option> <option>armish</option> <option>arm32</option> <option>atari</option> <option>aviion</option> <option>beagle</option> <option>cats</option> <option>hppa64</option> <option>hp300</option> <option>ia64</option> <option>mac68k</option> <option>mvme68k</option> <option>mvme88k</option> <option>mvmeppc</option> <option>palm</option> <option>pc532</option> <option>pegasos</option> <option>pmax</option> <option>powerpc</option> <option>sgi</option> <option>socppc</option> <option>solbourne</option> <option>sparc</option> <option>sun3</option> <option>vax</option> <option>wgrisc</option> <option>x68k</option> <option>zaurus</option> </select> <select name="manpath" aria-label="Manual path"> <option selected="selected">OpenBSD-current</option> <option>OpenBSD-7.6</option> <option>OpenBSD-7.5</option> <option>OpenBSD-7.4</option> <option>OpenBSD-7.3</option> <option>OpenBSD-7.2</option> <option>OpenBSD-7.1</option> <option>OpenBSD-7.0</option> <option>OpenBSD-6.9</option> <option>OpenBSD-6.8</option> <option>OpenBSD-6.7</option> <option>OpenBSD-6.6</option> <option>OpenBSD-6.5</option> <option>OpenBSD-6.4</option> <option>OpenBSD-6.3</option> <option>OpenBSD-6.2</option> <option>OpenBSD-6.1</option> <option>OpenBSD-6.0</option> <option>OpenBSD-5.9</option> <option>OpenBSD-5.8</option> <option>OpenBSD-5.7</option> <option>OpenBSD-5.6</option> <option>OpenBSD-5.5</option> <option>OpenBSD-5.4</option> <option>OpenBSD-5.3</option> <option>OpenBSD-5.2</option> <option>OpenBSD-5.1</option> <option>OpenBSD-5.0</option> <option>OpenBSD-4.9</option> <option>OpenBSD-4.8</option> <option>OpenBSD-4.7</option> <option>OpenBSD-4.6</option> <option>OpenBSD-4.5</option> <option>OpenBSD-4.4</option> <option>OpenBSD-4.3</option> <option>OpenBSD-4.2</option> <option>OpenBSD-4.1</option> <option>OpenBSD-4.0</option> <option>OpenBSD-3.9</option> <option>OpenBSD-3.8</option> <option>OpenBSD-3.7</option> <option>OpenBSD-3.6</option> <option>OpenBSD-3.5</option> <option>OpenBSD-3.4</option> <option>OpenBSD-3.3</option> <option>OpenBSD-3.2</option> <option>OpenBSD-3.1</option> <option>OpenBSD-3.0</option> <option>OpenBSD-2.9</option> <option>OpenBSD-2.8</option> <option>OpenBSD-2.7</option> <option>OpenBSD-2.6</option> <option>OpenBSD-2.5</option> <option>OpenBSD-2.4</option> <option>OpenBSD-2.3</option> <option>OpenBSD-2.2</option> </select> </fieldset> </form> </header> <hr> <div class="head" role="doc-pageheader" aria-label="Manual header line"><span class="head-ltitle">IFMEDIA(4)</span> <span class="head-vol">Device Drivers Manual</span> <span class="head-rtitle">IFMEDIA(4)</span></div> <main class="manual-text"> <section class="Sh"> <h2 class="Sh" id="NAME"><a class="permalink" href="#NAME">NAME</a></h2> <p class="Pp"><code class="Nm">ifmedia</code> — <span class="Nd" role="doc-subtitle">network interface media settings</span></p> </section> <section class="Sh"> <h2 class="Sh" id="SYNOPSIS"><a class="permalink" href="#SYNOPSIS">SYNOPSIS</a></h2> <p class="Pp"><code class="In">#include <<a class="In">sys/socket.h</a>></code> <br/> <code class="In">#include <<a class="In">net/if.h</a>></code> <br/> <code class="In">#include <<a class="In">net/if_media.h</a>></code></p> </section> <section class="Sh"> <h2 class="Sh" id="DESCRIPTION"><a class="permalink" href="#DESCRIPTION">DESCRIPTION</a></h2> <p class="Pp">The <code class="Nm">ifmedia</code> interface provides a consistent method for querying and setting network interface media and media options. The media is typically set using the <a class="Xr" href="/ifconfig.8" aria-label="ifconfig, section 8">ifconfig(8)</a> command.</p> <p class="Pp">Currently these link types are supported by <code class="Nm">ifmedia</code>:</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_ETHER"><a class="permalink" href="#IFM_ETHER"><code class="Dv">IFM_ETHER</code></a></dt> <dd>Ethernet</dd> <dt id="IFM_FDDI"><a class="permalink" href="#IFM_FDDI"><code class="Dv">IFM_FDDI</code></a></dt> <dd>FDDI</dd> <dt id="IFM_IEEE80211"><a class="permalink" href="#IFM_IEEE80211"><code class="Dv">IFM_IEEE80211</code></a></dt> <dd>IEEE802.11 Wireless LAN</dd> <dt id="IFM_TDM"><a class="permalink" href="#IFM_TDM"><code class="Dv">IFM_TDM</code></a></dt> <dd>Time Division Multiplex</dd> <dt id="IFM_CARP"><a class="permalink" href="#IFM_CARP"><code class="Dv">IFM_CARP</code></a></dt> <dd>CARP</dd> </dl> </div> <p class="Pp">The following sections describe the possible media settings for each link type. Not all of these are supported by every device; refer to your device's manual page for more information.</p> <p class="Pp">The lists below provide the possible names of each media type or option. The first name in the list is the canonical name of the media type or option. Additional names are acceptable aliases for the media type or option.</p> </section> <section class="Sh"> <h2 class="Sh" id="COMMON_MEDIA_TYPES_AND_OPTIONS"><a class="permalink" href="#COMMON_MEDIA_TYPES_AND_OPTIONS">COMMON MEDIA TYPES AND OPTIONS</a></h2> <p class="Pp">The following media types are shared by all link types:</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_AUTO"><a class="permalink" href="#IFM_AUTO"><code class="Dv">IFM_AUTO</code></a></dt> <dd>Autoselect the best media. [autoselect, auto]</dd> <dt id="IFM_MANUAL"><a class="permalink" href="#IFM_MANUAL"><code class="Dv">IFM_MANUAL</code></a></dt> <dd>Jumper or switch on device selects media. [manual]</dd> <dt id="IFM_NONE"><a class="permalink" href="#IFM_NONE"><code class="Dv">IFM_NONE</code></a></dt> <dd>Deselect all media. [none]</dd> </dl> </div> <p class="Pp">The following media options are shared by all link types:</p> <div class="Bd-indent"> <dl class="Bl-tag"> <dt id="IFM_FDX"><a class="permalink" href="#IFM_FDX"><code class="Dv">IFM_FDX</code></a></dt> <dd>Place the device into full-duplex mode. This option only has meaning if the device is normally not full-duplex.</dd> <dt id="IFM_HDX"><a class="permalink" href="#IFM_HDX"><code class="Dv">IFM_HDX</code></a></dt> <dd>Place the device into half-duplex mode. This option only has meaning if the device is normally not half-duplex. [half-duplex, hdx]</dd> <dt id="IFM_FLOW"><a class="permalink" href="#IFM_FLOW"><code class="Dv">IFM_FLOW</code></a></dt> <dd>Enable hardware flow control on device.</dd> <dt id="IFM_FLAG0"><a class="permalink" href="#IFM_FLAG0"><code class="Dv">IFM_FLAG0</code></a></dt> <dd>Driver-defined flag. [flag0]</dd> <dt id="IFM_FLAG1"><a class="permalink" href="#IFM_FLAG1"><code class="Dv">IFM_FLAG1</code></a></dt> <dd>Driver-defined flag. [flag1]</dd> <dt id="IFM_FLAG2"><a class="permalink" href="#IFM_FLAG2"><code class="Dv">IFM_FLAG2</code></a></dt> <dd>Driver-defined flag. [flag2]</dd> <dt id="IFM_LOOP"><a class="permalink" href="#IFM_LOOP"><code class="Dv">IFM_LOOP</code></a></dt> <dd>Place the device into hardware loopback mode. [loopback, hw-loopback, loop]</dd> </dl> </div> </section> <section class="Sh"> <h2 class="Sh" id="MEDIA_TYPES_AND_OPTIONS_FOR_ETHERNET"><a class="permalink" href="#MEDIA_TYPES_AND_OPTIONS_FOR_ETHERNET">MEDIA TYPES AND OPTIONS FOR ETHERNET</a></h2> <p class="Pp">The following media types are defined for Ethernet:</p> <div class="Bd-indent"> <dl class="Bl-tag"> <dt id="IFM_10_T"><a class="permalink" href="#IFM_10_T"><code class="Dv">IFM_10_T</code></a></dt> <dd>10BASE-T, 10Mb/s over unshielded twisted pair, RJ45 connector. [10baseT, UTP, 10UTP]</dd> <dt id="IFM_10_2"><a class="permalink" href="#IFM_10_2"><code class="Dv">IFM_10_2</code></a></dt> <dd>10BASE2, 10Mb/s over coaxial cable, BNC connector; also called Thinnet. [10base2, BNC, 10BNC]</dd> <dt id="IFM_10_5"><a class="permalink" href="#IFM_10_5"><code class="Dv">IFM_10_5</code></a></dt> <dd>10BASE5, 10Mb/s over 15-wire cables, DB15 connector; also called AUI. [10base5, AUI, 10AUI]</dd> <dt id="IFM_10_STP"><a class="permalink" href="#IFM_10_STP"><code class="Dv">IFM_10_STP</code></a></dt> <dd>10BASE-STP, 10Mb/s over shielded twisted pair, DB9 connector. [10baseSTP, STP, 10STP]</dd> <dt id="IFM_10_FL"><a class="permalink" href="#IFM_10_FL"><code class="Dv">IFM_10_FL</code></a></dt> <dd>10BASE-FL, 10Mb/s over fiber optic cables. [10baseFL, FL, 10FL]</dd> <dt id="IFM_100_TX"><a class="permalink" href="#IFM_100_TX"><code class="Dv">IFM_100_TX</code></a></dt> <dd>100BASE-TX, 100Mb/s over unshielded twisted pair, RJ45 connector. [100baseTX, 100TX]</dd> <dt id="IFM_100_FX"><a class="permalink" href="#IFM_100_FX"><code class="Dv">IFM_100_FX</code></a></dt> <dd>100BASE-FX, 100Mb/s over fiber optic cables. [100baseFX, 100FX]</dd> <dt id="IFM_100_T4"><a class="permalink" href="#IFM_100_T4"><code class="Dv">IFM_100_T4</code></a></dt> <dd>100BASE-T4, 100Mb/s over 4-wire (category 3) unshielded twisted pair, RJ45 connector. [100baseT4, 100T4]</dd> <dt id="IFM_100_T2"><a class="permalink" href="#IFM_100_T2"><code class="Dv">IFM_100_T2</code></a></dt> <dd>100BASE-T2. [100baseT2, 100T2]</dd> <dt id="IFM_100_VG"><a class="permalink" href="#IFM_100_VG"><code class="Dv">IFM_100_VG</code></a></dt> <dd>100VG-AnyLAN. [100baseVG, 100VG]</dd> <dt id="IFM_1000_SX"><a class="permalink" href="#IFM_1000_SX"><code class="Dv">IFM_1000_SX</code></a></dt> <dd>1000BASE-SX, 1Gb/s over multi-mode fiber optic cables. [1000baseSX, 1000SX]</dd> <dt id="IFM_1000_LX"><a class="permalink" href="#IFM_1000_LX"><code class="Dv">IFM_1000_LX</code></a></dt> <dd>1000BASE-LX, 1Gb/s over single-mode fiber optic cables. [1000baseLX, 1000LX]</dd> <dt id="IFM_1000_CX"><a class="permalink" href="#IFM_1000_CX"><code class="Dv">IFM_1000_CX</code></a></dt> <dd>1000BASE-CX, 1Gb/s over shielded twisted pair. [1000baseCX, 1000CX]</dd> <dt id="IFM_1000_T"><a class="permalink" href="#IFM_1000_T"><code class="Dv">IFM_1000_T</code></a></dt> <dd>1000BASE-T, 1Gb/s over category 5 unshielded twisted pair, RJ45 connector. [1000baseT, 1000T]</dd> <dt id="IFM_1000_TX"><a class="permalink" href="#IFM_1000_TX"><code class="Dv">IFM_1000_TX</code></a></dt> <dd>Compatibility for 1000BASE-T. [1000baseTX, 1000TX]</dd> <dt id="IFM_2500_SX"><a class="permalink" href="#IFM_2500_SX"><code class="Dv">IFM_2500_SX</code></a></dt> <dd>2500BASE-SX, 2.5Gb/s over multi-mode fiber optic cables. [2500baseSX, 2500SX]</dd> <dt id="IFM_2500_T"><a class="permalink" href="#IFM_2500_T"><code class="Dv">IFM_2500_T</code></a></dt> <dd>2500BASE-T, 2.5Gb/s over unshielded twisted pair, RJ45 connector. [2500baseT, 2500BASE-T]</dd> <dt id="IFM_10G_CX4"><a class="permalink" href="#IFM_10G_CX4"><code class="Dv">IFM_10G_CX4</code></a></dt> <dd>10GBASE-CX4, 10Gb/s over XAUI 4-lane PCS and copper cables. [10GbaseCX4, 10GCX4, 10GBASE-CX4]</dd> <dt id="IFM_10G_LR"><a class="permalink" href="#IFM_10G_LR"><code class="Dv">IFM_10G_LR</code></a></dt> <dd>10GBASE-LR, 10Gb/s over single-mode fiber optic cables. [10GbaseLR, 10GLR, 10GBASE-LR]</dd> <dt id="IFM_10G_SFP_CU"><a class="permalink" href="#IFM_10G_SFP_CU"><code class="Dv">IFM_10G_SFP_CU</code></a></dt> <dd>10GSFP+Cu, 10Gb/s over SFP+ Direct Attach cables. [10GSFP+Cu, 10GCu]</dd> <dt id="IFM_10G_SR"><a class="permalink" href="#IFM_10G_SR"><code class="Dv">IFM_10G_SR</code></a></dt> <dd>10GBASE-SR, 10Gb/s over multi-mode fiber optic cables. [10GbaseSR, 10GSR, 10GBASE-SR]</dd> <dt id="IFM_10G_T"><a class="permalink" href="#IFM_10G_T"><code class="Dv">IFM_10G_T</code></a></dt> <dd>10GBASE-T, 10Gb/s over unshielded twisted pair, RJ45 connector. [10GbaseT, 10GT, 10GBASE-T]</dd> <dt id="IFM_HPNA_1"><a class="permalink" href="#IFM_HPNA_1"><code class="Dv">IFM_HPNA_1</code></a></dt> <dd>HomePNA 1.0, 1Mb/s over 2-wire (category 3) unshielded twisted pair [HomePNA1, HPNA1]</dd> </dl> </div> <p class="Pp">The following media options are defined for Ethernet:</p> <div class="Bd-indent"> <dl class="Bl-tag"> <dt id="IFM_ETH_MASTER"><a class="permalink" href="#IFM_ETH_MASTER"><code class="Dv">IFM_ETH_MASTER</code></a></dt> <dd>Configure a 1000BASE-T PHY as a MASTER PHY.</dd> <dt id="IFM_ETH_RXPAUSE"><a class="permalink" href="#IFM_ETH_RXPAUSE"><code class="Dv">IFM_ETH_RXPAUSE</code></a></dt> <dd>Receive flow control is enabled on the 1000BASE-T PHY.</dd> <dt id="IFM_ETH_TXPAUSE"><a class="permalink" href="#IFM_ETH_TXPAUSE"><code class="Dv">IFM_ETH_TXPAUSE</code></a></dt> <dd>Transmit flow control is enabled on the 1000BASE-T PHY.</dd> </dl> </div> </section> <section class="Sh"> <h2 class="Sh" id="MEDIA_TYPES_AND_OPTIONS_FOR_FDDI"><a class="permalink" href="#MEDIA_TYPES_AND_OPTIONS_FOR_FDDI">MEDIA TYPES AND OPTIONS FOR FDDI</a></h2> <p class="Pp">The following media types are defined for FDDI:</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_FDDI_SMF"><a class="permalink" href="#IFM_FDDI_SMF"><code class="Dv">IFM_FDDI_SMF</code></a></dt> <dd>Single-mode fiber. [Single-mode, SMF]</dd> <dt id="IFM_FDDI_MMF"><a class="permalink" href="#IFM_FDDI_MMF"><code class="Dv">IFM_FDDI_MMF</code></a></dt> <dd>Multi-mode fiber. [Multi-mode, MMF]</dd> <dt id="IFM_FDDI_UTP"><a class="permalink" href="#IFM_FDDI_UTP"><code class="Dv">IFM_FDDI_UTP</code></a></dt> <dd>Unshielded twisted pair, RJ45 connector. [UTP, CDDI]</dd> </dl> </div> <p class="Pp">The following media options are defined for FDDI:</p> <div class="Bd-indent"> <dl class="Bl-tag"> <dt id="IFM_FDDI_DA"><a class="permalink" href="#IFM_FDDI_DA"><code class="Dv">IFM_FDDI_DA</code></a></dt> <dd>Dual-attached station vs. Single-attached station. [dual-attach, das]</dd> </dl> </div> </section> <section class="Sh"> <h2 class="Sh" id="MEDIA_TYPES_AND_OPTIONS_FOR_IEEE802.11_WIRELESS_LAN"><a class="permalink" href="#MEDIA_TYPES_AND_OPTIONS_FOR_IEEE802.11_WIRELESS_LAN">MEDIA TYPES AND OPTIONS FOR IEEE802.11 WIRELESS LAN</a></h2> <p class="Pp">The following media modes are defined for IEEE802.11 Wireless LAN:</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_IEEE80211_11A"><a class="permalink" href="#IFM_IEEE80211_11A"><code class="Dv">IFM_IEEE80211_11A</code></a></dt> <dd>5GHz, OFDM mode. [11a]</dd> <dt id="IFM_IEEE80211_11B"><a class="permalink" href="#IFM_IEEE80211_11B"><code class="Dv">IFM_IEEE80211_11B</code></a></dt> <dd>2GHz, DSSS/CCK mode. [11b]</dd> <dt id="IFM_IEEE80211_11G"><a class="permalink" href="#IFM_IEEE80211_11G"><code class="Dv">IFM_IEEE80211_11G</code></a></dt> <dd>2GHz, DSSS/CCK/OFDM mode. [11g]</dd> <dt id="IFM_IEEE80211_FH"><a class="permalink" href="#IFM_IEEE80211_FH"><code class="Dv">IFM_IEEE80211_FH</code></a></dt> <dd>2GHz, GFSK mode. [fh]</dd> <dt id="IFM_IEEE80211_11N"><a class="permalink" href="#IFM_IEEE80211_11N"><code class="Dv">IFM_IEEE80211_11N</code></a></dt> <dd>2GHz/5GHz, HT mode. [11n]</dd> <dt id="IFM_IEEE80211_11AC"><a class="permalink" href="#IFM_IEEE80211_11AC"><code class="Dv">IFM_IEEE80211_11AC</code></a></dt> <dd>5GHz, VHT mode. [11ac]</dd> </dl> </div> <p class="Pp">The following media options are defined for IEEE802.11 Wireless LAN:</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_IEEE80211_ADHOC"><a class="permalink" href="#IFM_IEEE80211_ADHOC"><code class="Dv">IFM_IEEE80211_ADHOC</code></a></dt> <dd>Ad-hoc mode. [adhoc]</dd> <dt id="IFM_IEEE80211_HOSTAP"><a class="permalink" href="#IFM_IEEE80211_HOSTAP"><code class="Dv">IFM_IEEE80211_HOSTAP</code></a></dt> <dd>Host Access Point mode. [hostap]</dd> <dt id="IFM_IEEE80211_IBSS"><a class="permalink" href="#IFM_IEEE80211_IBSS"><code class="Dv">IFM_IEEE80211_IBSS</code></a></dt> <dd>IBSS mode. [ibss]</dd> <dt id="IFM_IEEE80211_IBSSMASTER"><a class="permalink" href="#IFM_IEEE80211_IBSSMASTER"><code class="Dv">IFM_IEEE80211_IBSSMASTER</code></a></dt> <dd>IBSS master mode. [ibssmaster]</dd> <dt id="IFM_IEEE80211_MONITOR"><a class="permalink" href="#IFM_IEEE80211_MONITOR"><code class="Dv">IFM_IEEE80211_MONITOR</code></a></dt> <dd>Monitor mode. [monitor]</dd> </dl> </div> <p class="Pp" id="ad-hoc">All of the above media options are mutually exclusive. If no media option is used, the wireless interface will try to find an access point to connect to. <code class="Cm">hostap</code> mode allows the wireless interface to act as an access point for other 802.11 devices. <code class="Cm">ibss</code> mode is the standardized method of operating without an access point, with each participating device taking on part of the role of an access point. <code class="Cm">adhoc</code> mode, more accurately known as <a class="permalink" href="#ad-hoc"><i class="Em">ad-hoc demo mode</i></a>, is not specified by the IEEE 802.11 standard and only works with <a class="Xr" href="/wi.4" aria-label="wi, section 4">wi(4)</a> devices. Likewise, <code class="Cm">ibssmaster</code> mode only works with <a class="Xr" href="/wi.4" aria-label="wi, section 4">wi(4)</a> devices. On standard 802.11 networks the IBSS master role is assigned automatically.</p> <p class="Pp">The channels detailed below are defined for IEEE802.11 Wireless LAN in the 2.4GHz band. The list of available frequencies is dependent on radio regulations specified by regional authorities. Recognized regulatory authorities include the FCC (United States), ETSI (Europe), and Japan. Frequencies in the table are specified in MHz.</p> <table class="Bl-column Bd-indent"> <tr id="Channel"> <td><a class="permalink" href="#Channel"><i class="Em">Channel</i></a></td> <td><a class="permalink" href="#FCC"><i class="Em" id="FCC">FCC</i></a></td> <td><a class="permalink" href="#ETSI"><i class="Em" id="ETSI">ETSI</i></a></td> <td><a class="permalink" href="#Japan"><i class="Em" id="Japan">Japan</i></a></td> </tr> <tr> <td>1</td> <td>2412</td> <td>2412</td> <td>2412</td> </tr> <tr> <td>2</td> <td>2417</td> <td>2417</td> <td>2417</td> </tr> <tr> <td>3</td> <td>2422</td> <td>2422</td> <td>2422</td> </tr> <tr> <td>4</td> <td>2427</td> <td>2427</td> <td>2427</td> </tr> <tr> <td>5</td> <td>2432</td> <td>2432</td> <td>2432</td> </tr> <tr> <td>6</td> <td>2437</td> <td>2437</td> <td>2437</td> </tr> <tr> <td>7</td> <td>2442</td> <td>2442</td> <td>2442</td> </tr> <tr> <td>8</td> <td>2447</td> <td>2447</td> <td>2447</td> </tr> <tr> <td>9</td> <td>2452</td> <td>2452</td> <td>2452</td> </tr> <tr> <td>10</td> <td>2457</td> <td>2457</td> <td>2457</td> </tr> <tr> <td>11</td> <td>2462</td> <td>2462</td> <td>2462</td> </tr> <tr> <td>12</td> <td>-</td> <td>2467</td> <td>2467</td> </tr> <tr> <td>13</td> <td>-</td> <td>2472</td> <td>2472</td> </tr> <tr> <td>14</td> <td>-</td> <td>-</td> <td>2484</td> </tr> </table> <p class="Pp">The channels do overlap; the bandwidth required for each channel is about 20MHz. When using multiple channels in close proximity, it is suggested that channels be separated by at least 25MHz. In the US, this means that only channels 1, 6, and 11 may be used simultaneously without interference.</p> <p class="Pp">Channels in the 5GHz band are too numerous to list here. Regulation of their use, particularly outdoors, varies between countries. Users are advised to inform themselves about applicable regulations before configuring wireless LAN devices for use in the 5GHz band.</p> <p class="Pp">The following media types are defined for IEEE802.11 Wireless LAN:</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_IEEE80211_FH1"><a class="permalink" href="#IFM_IEEE80211_FH1"><code class="Dv">IFM_IEEE80211_FH1</code></a></dt> <dd>Frequency Hopping 1Mbps. [FH1]</dd> <dt id="IFM_IEEE80211_FH2"><a class="permalink" href="#IFM_IEEE80211_FH2"><code class="Dv">IFM_IEEE80211_FH2</code></a></dt> <dd>Frequency Hopping 2Mbps. [FH2]</dd> <dt id="IFM_IEEE80211_DS1"><a class="permalink" href="#IFM_IEEE80211_DS1"><code class="Dv">IFM_IEEE80211_DS1</code></a></dt> <dd>Direct Sequence 1Mbps. [DS1]</dd> <dt id="IFM_IEEE80211_DS2"><a class="permalink" href="#IFM_IEEE80211_DS2"><code class="Dv">IFM_IEEE80211_DS2</code></a></dt> <dd>Direct Sequence 2Mbps. [DS2]</dd> </dl> </div> <p class="Pp">The above media types were first introduced in the IEEE 802.11-1997 standard and are used in the 2.4GHz band only. Frequency Hopping Spread Spectrum modulation is incompatible with modern 802.11 networks. Direct Sequence Spread Spectrum modulation (DSSS) frames can still be used if backwards compatibility to 802.11b is enabled.</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_IEEE80211_DS5"><a class="permalink" href="#IFM_IEEE80211_DS5"><code class="Dv">IFM_IEEE80211_DS5</code></a></dt> <dd>Direct Sequence 5.5Mbps. [DS5]</dd> <dt id="IFM_IEEE80211_DS11"><a class="permalink" href="#IFM_IEEE80211_DS11"><code class="Dv">IFM_IEEE80211_DS11</code></a></dt> <dd>Direct Sequence 11Mbps. [DS11]</dd> <dt id="IFM_IEEE80211_DS22"><a class="permalink" href="#IFM_IEEE80211_DS22"><code class="Dv">IFM_IEEE80211_DS22</code></a></dt> <dd>Direct Sequence 22Mbps. [DS22]</dd> </dl> </div> <p class="Pp">The above media types were first introduced in the IEEE 802.11b-1999 standard and are used in the 2.4GHz band only. They use Complementary Code Keying (CCK) which, compared to frames sent at 1Mbps or 2Mbps, reduces the possible distance between transmitter and receiver.</p> <p class="Pp">Modern 802.11 networks remain compatible with 802.11b, even though DSSS frames are incompatible with modern 802.11 frames using OFDM. Co-existence with 802.11b requires OFDM transmitters to either risk frame collisions or “reserve” the medium with a separate preceding transmission that DSSS receivers are able to decode. This causes additional overhead which some 802.11 deployments avoid by deliberately disabling backwards compatibility with 802.11b.</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_IEEE80211_OFDM6"><a class="permalink" href="#IFM_IEEE80211_OFDM6"><code class="Dv">IFM_IEEE80211_OFDM6</code></a></dt> <dd>OFDM 6Mbps. [OFDM6]</dd> <dt id="IFM_IEEE80211_OFDM9"><a class="permalink" href="#IFM_IEEE80211_OFDM9"><code class="Dv">IFM_IEEE80211_OFDM9</code></a></dt> <dd>OFDM 9Mbps. [OFDM9]</dd> <dt id="IFM_IEEE80211_OFDM12"><a class="permalink" href="#IFM_IEEE80211_OFDM12"><code class="Dv">IFM_IEEE80211_OFDM12</code></a></dt> <dd>OFDM 12Mbps. [OFDM12]</dd> <dt id="IFM_IEEE80211_OFDM18"><a class="permalink" href="#IFM_IEEE80211_OFDM18"><code class="Dv">IFM_IEEE80211_OFDM18</code></a></dt> <dd>OFDM 18Mbps. [OFDM18]</dd> <dt id="IFM_IEEE80211_OFDM24"><a class="permalink" href="#IFM_IEEE80211_OFDM24"><code class="Dv">IFM_IEEE80211_OFDM24</code></a></dt> <dd>OFDM 24Mbps. [OFDM24]</dd> <dt id="IFM_IEEE80211_OFDM36"><a class="permalink" href="#IFM_IEEE80211_OFDM36"><code class="Dv">IFM_IEEE80211_OFDM36</code></a></dt> <dd>OFDM 36Mbps. [OFDM36]</dd> <dt id="IFM_IEEE80211_OFDM48"><a class="permalink" href="#IFM_IEEE80211_OFDM48"><code class="Dv">IFM_IEEE80211_OFDM48</code></a></dt> <dd>OFDM 48Mbps. [OFDM48]</dd> <dt id="IFM_IEEE80211_OFDM54"><a class="permalink" href="#IFM_IEEE80211_OFDM54"><code class="Dv">IFM_IEEE80211_OFDM54</code></a></dt> <dd>OFDM 54Mbps. [OFDM54]</dd> <dt id="IFM_IEEE80211_OFDM72"><a class="permalink" href="#IFM_IEEE80211_OFDM72"><code class="Dv">IFM_IEEE80211_OFDM72</code></a></dt> <dd>OFDM 72Mbps. [OFDM72]</dd> </dl> </div> <p class="Pp">The above media types were first introduced in the IEEE 802.11a-1999 standard for the 5GHz band, and in the IEEE 802.11g-2003 standard for the 2.4GHz band. OFDM with 72Mbps is a proprietary extension and was never standardized by IEEE.</p> <p class="Pp">Orthogonal Frequency Division Multiplexing (OFDM) is the current standard modulation technique for 802.11. Each 20MHz channel used by 802.11a and 802.11g provides space for 48 OFDM sub-carriers for data. The sub-carriers use BPSK, QPSK, 16QAM, or 64QAM modulation, combined with a particular coding rate for error correction at the receiver. The coding rate specifies how many data bits in a frame are transmitted without redundancy.</p> <table class="Bl-column Bd-indent"> <tr id="Modulation"> <td><a class="permalink" href="#Modulation"><i class="Em">Modulation</i></a></td> <td><a class="permalink" href="#Coding"><i class="Em" id="Coding">Coding Rate</i></a></td> <td><a class="permalink" href="#Mbit/s"><i class="Em" id="Mbit/s">Mbit/s</i></a></td> </tr> <tr> <td>BPSK</td> <td>1/2</td> <td>6</td> </tr> <tr> <td>BPSK</td> <td>3/4</td> <td>9</td> </tr> <tr> <td>QPSK</td> <td>1/2</td> <td>12</td> </tr> <tr> <td>QPSK</td> <td>3/4</td> <td>18</td> </tr> <tr> <td>16QAM</td> <td>1/2</td> <td>24</td> </tr> <tr> <td>16QAM</td> <td>3/4</td> <td>36</td> </tr> <tr> <td>64QAM</td> <td>1/2</td> <td>48</td> </tr> <tr> <td>64QAM</td> <td>3/4</td> <td>52</td> </tr> </table> <p class="Pp">The IEEE 802.11n-2009 standard for “High Throughput” (HT) wireless LAN defines additional sub-carriers, modulations, and coding rates. The channel bandwidth for data frame transmissions was optionally extended to 40MHz, with full backwards compatibility to 802.11a/b/g devices which cannot decode 40MHz transmissions. Several additional features were introduced, most notably MIMO (multiple-input, multiple-output). With MIMO, a data stream is divided across up to 4 “spatial streams”, which are transmitted in parallel by a corresponding amount of antennas. Each spatial stream is received with a dedicated antenna, and the spatial streams are de-multiplexed to obtain the original data stream.</p> <p class="Pp">802.11n assigns a numeric identifier to all possible combinations of modulation, coding rate, and number of spatial streams. This results in 77 distinct modulation and coding schemes, abbreviated as “MCS”.</p> <p class="Pp"><code class="Nm">ifmedia</code> supports HT_MCS0 up to HT_MCS31:</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_IEEE80211_HT_MCSx"><a class="permalink" href="#IFM_IEEE80211_HT_MCSx"><code class="Dv">IFM_IEEE80211_HT_MCSx</code></a></dt> <dd>HT OFDM MCS x (where x is in the range 0 - 31, inclusive). [HT-MCSx]</dd> </dl> </div> <p class="Pp">In practice, only MCS-0 to MCS-32 are supported by commonly available devices. The remaining MCS define combinations where distinct spatial streams employ distinct modulations, a feature which was not widely implemented by hardware vendors.</p> <p class="Pp">The IEEE 802.11ac-2013 standard for “Very High Throughput” (VHT) wireless LAN operates in the 5GHz band only. The channel bandwidth for data frame transmissions can be up to 160MHz wide. The MCS identifiers were redefined and vastly reduced in number. As a result, only VHT_MCS0 to VHT_MCS9 are defined for 802.11ac:</p> <p class="Pp"></p> <div class="Bd-indent"> <dl class="Bl-tag Bl-compact"> <dt id="IFM_IEEE80211_VHT_MCSx"><a class="permalink" href="#IFM_IEEE80211_VHT_MCSx"><code class="Dv">IFM_IEEE80211_VHT_MCSx</code></a></dt> <dd>VHT OFDM MCS x (where x is in the range 0 - 9, inclusive). [VHT-MCSx]</dd> </dl> </div> <p class="Pp">The number of spatial streams is no longer associated with a given VHT MCS identifier and must be specified as a separate “NSS” parameter. This parameter is not yet implemented by <code class="Nm">ifmedia</code>.</p> </section> <section class="Sh"> <h2 class="Sh" id="MEDIA_TYPES_AND_OPTIONS_FOR_TDM"><a class="permalink" href="#MEDIA_TYPES_AND_OPTIONS_FOR_TDM">MEDIA TYPES AND OPTIONS FOR TDM</a></h2> <p class="Pp">The following media types are defined for TDM:</p> <div class="Bd-indent"> <dl class="Bl-tag"> <dt id="IFM_TDM_E1"><a class="permalink" href="#IFM_TDM_E1"><code class="Dv">IFM_TDM_E1</code></a></dt> <dd>E1, 2048kb/s HDB3 encoded, G.703 clearchannel serial line. [e1]</dd> <dt id="IFM_TDM_E1_AMI"><a class="permalink" href="#IFM_TDM_E1_AMI"><code class="Dv">IFM_TDM_E1_AMI</code></a></dt> <dd>E1, 2048kb/s AMI encoded, G.703 clearchannel serial line. [e1-ami]</dd> <dt id="IFM_TDM_E1_AMI_G704"><a class="permalink" href="#IFM_TDM_E1_AMI_G704"><code class="Dv">IFM_TDM_E1_AMI_G704</code></a></dt> <dd>E1, 2048kb/s AMI encoded, G.704 structured serial line. [e1-ami-g.704]</dd> <dt id="IFM_TDM_E1_G704"><a class="permalink" href="#IFM_TDM_E1_G704"><code class="Dv">IFM_TDM_E1_G704</code></a></dt> <dd>E1, 2048kb/s HDB3 encoded, G.704 structured serial line. [e1-g.704]</dd> <dt id="IFM_TDM_E1_G704_CRC4"><a class="permalink" href="#IFM_TDM_E1_G704_CRC4"><code class="Dv">IFM_TDM_E1_G704_CRC4</code></a></dt> <dd>E1, 2048kb/s HDB3 encoded, G.704 structured serial line with CRC4 checksum. [e1-g.704-crc4]</dd> <dt id="IFM_TDM_E3"><a class="permalink" href="#IFM_TDM_E3"><code class="Dv">IFM_TDM_E3</code></a></dt> <dd>E3, 34368kb/s HDB3 encoded, G.703 clearchannel serial line. [e3]</dd> <dt id="IFM_TDM_E3_G751"><a class="permalink" href="#IFM_TDM_E3_G751"><code class="Dv">IFM_TDM_E3_G751</code></a></dt> <dd>E3, 34368kb/s HDB3 encoded, G.751 structured serial line. [e3-g.751]</dd> <dt id="IFM_TDM_E3_G832"><a class="permalink" href="#IFM_TDM_E3_G832"><code class="Dv">IFM_TDM_E3_G832</code></a></dt> <dd>E3, 34368kb/s HDB3 encoded, G.832 structured serial line. [e3-g.832]</dd> <dt id="IFM_TDM_T1"><a class="permalink" href="#IFM_TDM_T1"><code class="Dv">IFM_TDM_T1</code></a></dt> <dd>T1, 1536xkb/s B8ZS encoded, extended super frame (ESF) structured serial line. [t1]</dd> <dt id="IFM_TDM_T1_AMI"><a class="permalink" href="#IFM_TDM_T1_AMI"><code class="Dv">IFM_TDM_T1_AMI</code></a></dt> <dd>T1, 1536kb/s AMI encoded, super frame (SF) structured serial line. [t1-ami]</dd> <dt id="IFM_TDM_T3"><a class="permalink" href="#IFM_TDM_T3"><code class="Dv">IFM_TDM_T3</code></a></dt> <dd>T3, 44736kb/s B3ZS, C-bit structured serial line. [t3]</dd> <dt id="IFM_TDM_T3_M13"><a class="permalink" href="#IFM_TDM_T3_M13"><code class="Dv">IFM_TDM_T3_M13</code></a></dt> <dd>T3, 44736kb/s B3ZS, M13 structured serial line. [t3-m13]</dd> </dl> </div> <p class="Pp">The following media options are defined for TDM:</p> <div class="Bd-indent"> <dl class="Bl-tag"> <dt id="IFM_TDM_HDLC_CRC16"><a class="permalink" href="#IFM_TDM_HDLC_CRC16"><code class="Dv">IFM_TDM_HDLC_CRC16</code></a></dt> <dd>Cisco HDLC with 16-bit CRC checksum encoding. [hdlc-crc16]</dd> <dt id="IFM_TDM_FR_ANSI"><a class="permalink" href="#IFM_TDM_FR_ANSI"><code class="Dv">IFM_TDM_FR_ANSI</code></a></dt> <dd>ANSI/ITU Framerelay encoding. [framerelay-ansi, framerelay-itu]</dd> <dt id="IFM_TDM_FR_CISCO"><a class="permalink" href="#IFM_TDM_FR_CISCO"><code class="Dv">IFM_TDM_FR_CISCO</code></a></dt> <dd>Cisco Framerelay encoding. [framerelay-cisco]</dd> <dt id="IFM_TDM_PPP"><a class="permalink" href="#IFM_TDM_PPP"><code class="Dv">IFM_TDM_PPP</code></a></dt> <dd>PPP encoding. [ppp]</dd> </dl> </div> <p class="Pp">By default TDM interfaces will use Cisco HDLC encoding with a 32-bit CRC checksum.</p> <p class="Pp">The following media modes are defined for TDM:</p> <div class="Bd-indent"> <dl class="Bl-tag"> <dt id="IFM_TDM_MASTER"><a class="permalink" href="#IFM_TDM_MASTER"><code class="Dv">IFM_TDM_MASTER</code></a></dt> <dd>Use local clock source as master clock. [master]</dd> </dl> </div> </section> <section class="Sh"> <h2 class="Sh" id="MEDIA_TYPES_AND_OPTIONS_FOR_CARP"><a class="permalink" href="#MEDIA_TYPES_AND_OPTIONS_FOR_CARP">MEDIA TYPES AND OPTIONS FOR CARP</a></h2> <p class="Pp"><a class="Xr" href="/carp.4" aria-label="carp, section 4">carp(4)</a> does not support any media types or options.</p> </section> <section class="Sh"> <h2 class="Sh" id="SEE_ALSO"><a class="permalink" href="#SEE_ALSO">SEE ALSO</a></h2> <p class="Pp"><a class="Xr" href="/netintro.4" aria-label="netintro, section 4">netintro(4)</a>, <a class="Xr" href="/ifconfig.8" aria-label="ifconfig, section 8">ifconfig(8)</a></p> </section> <section class="Sh"> <h2 class="Sh" id="HISTORY"><a class="permalink" href="#HISTORY">HISTORY</a></h2> <p class="Pp">The <code class="Nm">ifmedia</code> interface first appeared in <span class="Ux">BSD/OS 3.0</span>. The implementation that appeared in <span class="Ux">NetBSD 1.3</span> was written by Jonathan Stone and Jason R. Thorpe to be compatible with the BSDI API. It has since gone through several revisions which have extended the API while maintaining backwards compatibility with the original API.</p> <p class="Pp" id="IEEE802.11">Support for the <a class="permalink" href="#IEEE802.11"><b class="Sy">IEEE802.11 Wireless LAN</b></a> link type was added in <span class="Ux">NetBSD 1.5</span>.</p> <p class="Pp" id="Host"><a class="permalink" href="#Host"><b class="Sy">Host AP</b></a> mode was added in <span class="Ux">OpenBSD 3.1</span>.</p> </section> </main> <div class="foot" role="doc-pagefooter" aria-label="Manual footer line"><span class="foot-left"></span><span class="foot-date">August 15, 2023</span> <span class="foot-os">OpenBSD-current</span></div> </body> </html>