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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<title>Link-Layer Header Types | TCPDUMP/LIBPCAP public repository</title>
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<!-- Start of LINK-LAYER HEADER TYPES section -->
<div class="post">
<h2 class="title">
<a name="intro">LINK-LAYER HEADER TYPES</a>
</h2>
<div class="entry">
<p>
This is a list of link-layer header types used in pcap and pcap-ng
capture files. The LINKTYPE_ name is the name given to that link-layer
header type, and the LINKTYPE_ value is the numerical value used in
capture files. The DLT_ name is the name corresponding to the value
returned by <code>pcap_datalink()</code> and
<code>pcap_datalink_ex()</code>; in most cases, the LINKTYPE_ value and
DLT_ value are the same, but, in some cases, they differ, for reasons of
binary compatibility, with the DLT_ value being different on different
platforms.
</p>
<p>
Note that these values correspond to particular header formats; there
might be multiple link-layer header types for a given link-layer
protocol, as, for a given link-layer header type, the header for the
link-layer protocol might be preceded by a pseudo-header giving
additional information, or might be transformed in some way from the way
it's specified for that link-layer protocol, e.g. fields in the
link-layer protocol header might be removed, added, moved, or modified.
</p>
<p>
Values not listed here are reserved:</p>
<ul><li>Values in the range 147 through
162 are reserved for private use; if you have some link-layer header
type that you want to use within your organization, with the capture
files using that link-layer header type not ever be sent outside your
organization, you can use one or more these values. No libpcap release
will use these for any purpose, nor will any tcpdump release use them,
either.
<p>
Do <strong>NOT</strong> use these in capture files that you expect
anybody not using your private versions of capture-file-reading tools to
read; in particular, do <strong>NOT</strong> use them in products,
otherwise you may find that people won't be able to use tcpdump, or
snort, or Wireshark, or... to read capture files from your
firewall/intrusion detection/traffic monitoring/etc. appliance, or
whatever product uses that link-layer header type value, and you may
also find that the developers of those applications will not accept
patches to let them read those files.
</p>
<p>
Also, do not use them if somebody might send you a capture using them
for <em>their</em> private type and tools using them for <em>your</em>
private type would have to read them.
</p>
<li>All other values are reserved for current or future uses. If you
need a value for a particular set of link-layer headers, you must
request one;
<ul>
<li> to do so, send a mail message to <a
href="mailto:[email protected]">[email protected]</a>.
<p>
Please include either an indication of the standard that describes the
link-layer headers, a link to a page describing the link-layer headers,
or a detailed description of the link-layer headers. If the headers do
not exactly match the description in a standard or standards - for
example, if fields are added, removed, or reordered, or have their size
or format changed, please describe the changes in detail.
</p>
<li> Send a pull request with the new value,
see: <a href="https://github.com/the-tcpdump-group/libpcap/blob/master/doc/DLT_ALLOCATE_HOWTO.md">DLT_ALLOCATE_HOWTO.md</a>
</ul>
<p>
Do <strong>NOT</strong> add new values to this list without asking
[email protected] for a value. Otherwise, you run the
risk of using a value that's already being used for some other purpose,
and of having tools that read libpcap-format captures not being able to
handle captures with your new link-layer header type value, with no hope
that they will ever be changed to do so (as that would destroy their
ability to read captures using that value for that other purpose).
<p>
Do <strong>NOT</strong> use any of these link-layer header type values
unless your link-layer headers <strong>EXACTLY</strong> match the
specification. If they do not exactly match, request your own
link-layer header type for them.
</p>
</ul>
</div>
<!-- End of LINK-LAYER HEADER TYPES section -->
</div>
<!-- Start of LINK-LAYER HEADER TYPE VALUES section -->
<div class="post">
<h2 class="title">
<a name="project-list">Link-layer header type values</a>
</h2>
<div class="entry">
<table class=linktypedlt>
<tr>
<th>LINKTYPE_ name</th>
<th>LINKTYPE_ value</th>
<th>Corresponding DLT_ name</th>
<th>Description</th>
</tr>
<tr>
<td class="symbol">LINKTYPE_NULL</td>
<td class="number">0</td>
<td class="symbol">DLT_NULL</td>
<td>
BSD loopback encapsulation; the link layer header is a 4-byte field, in
host byte order, containing a value of 2 for IPv4 packets, a value of
either 24, 28, or 30 for IPv6 packets, a value of 7 for OSI packets, or
a value of 23 for IPX packets. All of the IPv6 values correspond to
IPv6 packets; code reading files should check for all of them.
<p>Note that ``host byte order'' is the byte order of the machine on
which the packets are captured; if a live capture is being done, ``host
byte order'' is the byte order of the machine capturing the packets, but
if a ``savefile'' is being read, the byte order is not necessarily that
of the machine reading the capture file.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_ETHERNET</td>
<td class="number">1</td>
<td class="symbol">DLT_EN10MB</td>
<td>
<a href="https://ieeexplore.ieee.org/document/7428776/">IEEE
802.3</a> Ethernet (10Mb, 100Mb, 1000Mb, and up); the 10MB in the
DLT_ name is historical.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_AX25</td>
<td class="number">3</td>
<td class="symbol">DLT_AX25</td>
<td>
<a href="http://www.ax25.net/AX25.2.2-Jul%2098-2.pdf">AX.25</a> packet,
with nothing preceding it.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IEEE802_5</td>
<td class="number">6</td>
<td class="symbol">DLT_IEEE802</td>
<td>
IEEE 802.5 Token Ring; the IEEE802, without _5, in the DLT_ name is
historical.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_ARCNET_BSD</td>
<td class="number">7</td>
<td class="symbol">DLT_ARCNET</td>
<td>
ARCNET Data Packets, as described by the ARCNET Trade Association
standard <a href="https://web.archive.org/web/20100414154838/http://www.arcnet.com/resources/ata8781.pdf">ATA
878.1-1999</a>, but without the Starting Delimiter, Information Length,
or Frame Check Sequence fields, and with only the first ISU of the
Destination Identifier. For most packet types, ARCNET Trade Association
draft standard <a href="https://web.archive.org/web/20100414154914/http://www.arcnet.com/resources/ata8782.pdf">ATA
878.2</a> is also used. See also <a
href="https://tools.ietf.org/html/rfc1051">RFC 1051</a> and <a
href="https://tools.ietf.org/html/rfc1201">RFC 1201</a>; for RFC 1051
frames, ATA 878.2 is not used.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_SLIP</td>
<td class="number">8</td>
<td class="symbol">DLT_SLIP</td>
<td>
SLIP, encapsulated with
<a href="linktypes/LINKTYPE_SLIP.html">a LINKTYPE_SLIP header</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_PPP</td>
<td class="number">9</td>
<td class="symbol">DLT_PPP</td>
<td>
PPP, as per
<a href="https://tools.ietf.org/html/rfc1661">RFC 1661</a>
and
<a href="https://tools.ietf.org/html/rfc1662">RFC 1662</a>; if
the first 2 bytes are 0xff and 0x03, it's PPP in HDLC-like
framing, with the PPP header following those two bytes, otherwise it's
PPP without framing, and the packet begins with the PPP header. The
data in the frame is not octet-stuffed or bit-stuffed.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_FDDI</td>
<td class="number">10</td>
<td class="symbol">DLT_FDDI</td>
<td>
FDDI, as specified by ANSI INCITS 239-1994.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_PPP_HDLC</td>
<td class="number">50</td>
<td class="symbol">DLT_PPP_SERIAL</td>
<td>
PPP in HDLC-like framing, as per
<a href="https://tools.ietf.org/html/rfc1662"> RFC 1662</a>,
or Cisco PPP with HDLC
framing, as per <a href="https://tools.ietf.org/html/rfc1547#section-4.3.1">
section 4.3.1 of RFC 1547</a>; the first byte will be 0xFF
for PPP in HDLC-like framing, and will be 0x0F or 0x8F for Cisco PPP
with HDLC framing. The data in the frame is not octet-stuffed or
bit-stuffed.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_PPP_ETHER</td>
<td class="number">51</td>
<td class="symbol">DLT_PPP_ETHER</td>
<td>
PPPoE; the packet begins with a PPPoE header, as per
<a href="https://tools.ietf.org/html/rfc2516">RFC 2516</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_ATM_RFC1483</td>
<td class="number">100</td>
<td class="symbol">DLT_ATM_RFC1483</td>
<td>
<a href="https://tools.ietf.org/html/rfc1483">RFC 1483</a>
LLC/SNAP-encapsulated ATM; the packet begins with an
<a href="https://www.iso.org/standard/30174.html">ISO 8802-2</a>
(formerly known as IEEE 802.2) LLC header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_RAW</td>
<td class="number">101</td>
<td class="symbol">DLT_RAW</td>
<td>
Raw IP; the packet begins with an IPv4 or IPv6 header, with the
"version" field of the header indicating whether it's an IPv4 or IPv6
header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_C_HDLC</td>
<td class="number">104</td>
<td class="symbol">DLT_C_HDLC</td>
<td>
Cisco PPP with HDLC framing, as per
<a href="https://tools.ietf.org/html/rfc1547#section-4.3.1">
section 4.3.1 of RFC 1547</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IEEE802_11</td>
<td class="number">105</td>
<td class="symbol">DLT_IEEE802_11</td>
<td>
<a href="https://ieeexplore.ieee.org/document/7786995/">IEEE 802.11</a>
wireless LAN.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_FRELAY</td>
<td class="number">107</td>
<td class="symbol">DLT_FRELAY</td>
<td>
Frame Relay LAPF frames, beginning with a <a
href="https://www.itu.int/rec/T-REC-Q.922/en/">ITU-T Recommendation
Q.922</a> LAPF header starting with the address field, and without an
FCS at the end of the frame.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_LOOP</td>
<td class="number">108</td>
<td class="symbol">DLT_LOOP</td>
<td>
OpenBSD loopback encapsulation; the link-layer header is a 4-byte field,
in <em>network</em> byte order, containing a value of 2 for IPv4
packets, a value of either 24, 28, or 30 for IPv6 packets, a value of 7
for OSI packets, or a value of 23 for IPX packets. All of the IPv6
values correspond to IPv6 packets; code reading files should check for
all of them.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_LINUX_SLL</td>
<td class="number">113</td>
<td class="symbol">DLT_LINUX_SLL</td>
<td>
<a href="linktypes/LINKTYPE_LINUX_SLL.html">Linux "cooked" capture
encapsulation</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_LTALK</td>
<td class="number">114</td>
<td class="symbol">DLT_LTALK</td>
<td>
Apple LocalTalk; the packet begins with an AppleTalk LocalTalk Link
Access Protocol header, as described in chapter 1 of <a
href="https://web.archive.org/web/20040719034527/http://developer.apple.com:80/macos/opentransport/docs/dev/Inside_AppleTalk.pdf">Inside
AppleTalk, Second Edition</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_PFLOG</td>
<td class="number">117</td>
<td class="symbol">DLT_PFLOG</td>
<td>
OpenBSD pflog; the link-layer header contains a
"struct pfloghdr"
structure, as defined by the host on which the file was saved. (This
differs from operating system to operating system and release to
release; there is nothing in the file to indicate what the layout of
that structure is.)
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IEEE802_11_PRISM</td>
<td class="number">119</td>
<td class="symbol">DLT_PRISM_HEADER</td>
<td>
<a href="linktypes/LINKTYPE_IEEE802_11_PRISM.html">Prism monitor mode
information</a> followed by an 802.11 header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IP_OVER_FC</td>
<td class="number">122</td>
<td class="symbol">DLT_IP_OVER_FC</td>
<td>
<a href="https://tools.ietf.org/html/rfc2625">RFC 2625</a>
IP-over-Fibre Channel, with the link-layer header being the
Network_Header as described in that RFC.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_SUNATM</td>
<td class="number">123</td>
<td class="symbol">DLT_SUNATM</td>
<td>
ATM traffic, encapsulated as per
<a href="linktypes/LINKTYPE_SUNATM.html">the scheme used by SunATM
devices</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IEEE802_11_RADIOTAP</td>
<td class="number">127</td>
<td class="symbol">DLT_IEEE802_11_RADIO</td>
<td>
<a href="http://www.radiotap.org/">Radiotap link-layer information</a>
followed by an 802.11 header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_ARCNET_LINUX</td>
<td class="number">129</td>
<td class="symbol">DLT_ARCNET_LINUX</td>
<td>
ARCNET Data Packets, as described by the ARCNET Trade Association
standard <a href="https://web.archive.org/web/20100414154838/http://www.arcnet.com/resources/ata8781.pdf">ATA
878.1-1999</a>, but without the Starting Delimiter, Information Length,
or Frame Check Sequence fields, with only the first ISU of the
Destination Identifier, and with an extra two-ISU "offset" field
following the Destination Identifier. For most packet types, ARCNET
Trade Association draft standard
<a href="https://web.archive.org/web/20100414154914/http://www.arcnet.com/resources/ata8782.pdf">ATA 878.2</a> is
also used; however, no exception frames are supplied, and reassembled
frames, rather than fragments, are supplied. See also <a
href="https://tools.ietf.org/html/rfc1051">RFC 1051</a> and <a
href="https://tools.ietf.org/html/rfc1201">RFC 1201</a>; for RFC 1051
frames, ATA 878.2 is not used.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_APPLE_IP_OVER_IEEE1394</td>
<td class="number">138</td>
<td class="symbol">DLT_APPLE_IP_OVER_IEEE1394</td>
<td>
<a href="linktypes/LINKTYPE_APPLE_IP_OVER_IEEE1394.html">Apple
IP-over-IEEE 1394 cooked header</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_MTP2_WITH_PHDR</td>
<td class="number">139</td>
<td class="symbol">DLT_MTP2_WITH_PHDR</td>
<td>
Signaling System 7 Message Transfer Part Level 2, as specified by <a
href="https://www.itu.int/rec/T-REC-Q.703/en/">ITU-T Recommendation
Q.703</a>, preceded by a pseudo-header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_MTP2</td>
<td class="number">140</td>
<td class="symbol">DLT_MTP2</td>
<td>
Signaling System 7 Message Transfer Part Level 2, as specified by <a
href="https://www.itu.int/rec/T-REC-Q.703/en/">ITU-T Recommendation
Q.703</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_MTP3</td>
<td class="number">141</td>
<td class="symbol">DLT_MTP3</td>
<td>
Signaling System 7 Message Transfer Part Level 3, as specified by <a
href="https://www.itu.int/rec/T-REC-Q.704/en/">ITU-T Recommendation
Q.704</a>, with no MTP2 header preceding the MTP3 packet.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_SCCP</td>
<td class="number">142</td>
<td class="symbol">DLT_SCCP</td>
<td>
Signaling System 7 Signalling Connection Control Part, as specified by
<a href="https://www.itu.int/rec/T-REC-Q.711/en/">ITU-T Recommendation
Q.711</a>,
<a href="https://www.itu.int/rec/T-REC-Q.712/en/">ITU-T Recommendation
Q.712</a>,
<a href="https://www.itu.int/rec/T-REC-Q.713/en/">ITU-T Recommendation
Q.713</a>, and
<a href="https://www.itu.int/rec/T-REC-Q.714/en/">ITU-T Recommendation
Q.714</a>, with no MTP3 or MTP2 headers preceding the SCCP packet.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_DOCSIS</td>
<td class="number">143</td>
<td class="symbol">DLT_DOCSIS</td>
<td>
DOCSIS MAC frames, as described by <a
href="https://apps.cablelabs.com/specification/CM-SP-MULPIv3.1">the
DOCSIS 3.1 MAC and Upper Layer Protocols Interface Specification</a> or
earlier specifications for MAC frames.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_LINUX_IRDA</td>
<td class="number">144</td>
<td class="symbol">DLT_LINUX_IRDA</td>
<td>
Linux-IrDA packets, with a
<a href="linktypes/LINKTYPE_LINUX_IRDA.html">LINKTYPE_LINUX_IRDA
header</a>,
with the payload for IrDA frames beginning with by the IrLAP header as
defined by
<a href="https://www.irda.org/library-of-specs">IrDA
Data Specifications</a>, including the IrDA Link Access Protocol
specification.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_USER0-LINKTYPE-USER15</td>
<td class="number">147-162</td>
<td class="symbol">DLT_USER0-DLT_USER15</td>
<td>
Reserved for private use; see above.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IEEE802_11_AVS</td>
<td class="number">163</td>
<td class="symbol">DLT_IEEE802_11_RADIO_AVS</td>
<td>
<a href="http://web.archive.org/web/20040803232023/http://www.shaftnet.org/~pizza/software/capturefrm.txt">AVS monitor mode
information</a> followed by an 802.11 header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_BACNET_MS_TP</td>
<td class="number">165</td>
<td class="symbol">DLT_BACNET_MS_TP</td>
<td>
BACnet MS/TP frames, as specified by section 9.3 <b>MS/TP Frame
Format</b> of
<a
href="http://www.ashrae.org/resources--publications/bookstore/standard-135">ANSI/ASHRAE
Standard 135, BACnet® - A Data Communication Protocol for Building
Automation and Control Networks</a>, including the preamble and, if
present, the Data CRC.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_PPP_PPPD</td>
<td class="number">166</td>
<td class="symbol">DLT_PPP_PPPD</td>
<td>
PPP in HDLC-like encapsulation, like LINKTYPE_PPP_HDLC, but with the
0xff address byte replaced by a direction indication - 0x00 for incoming
and 0x01 for outgoing.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_GPRS_LLC</td>
<td class="number">169</td>
<td class="symbol">DLT_GPRS_LLC</td>
<td>
General Packet Radio Service Logical Link Control, as defined by <a
href="https://portal.3gpp.org/desktopmodules/Specifications/SpecificationDetails.aspx?specificationId=224">3GPP TS 04.64</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_GPF_T</td>
<td class="number">170</td>
<td class="symbol">DLT_GPF_T</td>
<td>
Transparent-mapped generic framing procedure, as specified by
<a href="https://www.itu.int/rec/T-REC-G.7041/en">ITU-T
Recommendation G.7041/Y.1303</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_GPF_F</td>
<td class="number">171</td>
<td class="symbol">DLT_GPF_F</td>
<td>
Frame-mapped generic framing procedure, as specified by
<a href="https://www.itu.int/rec/T-REC-G.7041/en">ITU-T
Recommendation G.7041/Y.1303</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_LINUX_LAPD</td>
<td class="number">177</td>
<td class="symbol">DLT_LINUX_LAPD</td>
<td>
Link Access Procedures on the D Channel (LAPD) frames, as specified by
<a href="https://www.itu.int/rec/T-REC-Q.920/en">ITU-T
Recommendation Q.920</a>
and
<a href="https://www.itu.int/rec/T-REC-Q.921/en">ITU-T
Recommendation Q.921</a>, captured via vISDN, with a
<a href="linktypes/LINKTYPE_LINUX_LAPD.html">LINKTYPE_LINUX_LAPD
header</a>, followed by the Q.921 frame, starting with the address
field.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_MFR</td>
<td class="number">182</td>
<td class="symbol">DLT_MFR</td>
<td>
<a href="https://web.archive.org/web/20160427004354/https://www.broadband-forum.org/technical/download/FRF.16/frf16.1.pdf">FRF.16.1</a>
Multi-Link Frame Relay frames, beginning with an
<a href="https://web.archive.org/web/20181021041543/https://www.broadband-forum.org/technical/download/FRF.12/frf12.pdf">FRF.12</a>
Interface fragmentation format fragmentation header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_BLUETOOTH_HCI_H4</td>
<td class="number">187</td>
<td class="symbol">DLT_BLUETOOTH_HCI_H4</td>
<td>
Bluetooth HCI UART transport layer; the frame contains an HCI packet
indicator byte, as specified by the UART Transport Layer portion of the
most recent
<a href="https://web.archive.org/web/20130314201541/https://www.bluetooth.org/Technical/Specifications/adopted.htm">
Bluetooth Core specification</a>, followed by an HCI packet of the
specified packet type, as specified by the Host Controller Interface
Functional Specification portion of the most recent Bluetooth Core
Specification.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_USB_LINUX</td>
<td class="number">189</td>
<td class="symbol">DLT_USB_LINUX</td>
<td>
USB packets, beginning with a Linux USB header, as specified by the
<tt>struct usbmon_packet</tt> in the
<tt>Documentation/usb/usbmon.txt</tt> file in the Linux source tree.
Only the first 48 bytes of that header are present. All fields in the
header are in host byte order. When performing a live capture, the
host byte order is the byte order of the machine on which the packets
are captured. When reading a pcap file, the byte order is the byte
order for the file, as specified by the file's magic number; when
reading a pcapng file, the byte order is the byte order for the section
of the pcapng file, as specified by the Section Header Block.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_PPI</td>
<td class="number">192</td>
<td class="symbol">DLT_PPI</td>
<td>
Per-Packet Information information, as specified by <a
href="https://web.archive.org/web/20160328114748/http://www.cacetech.com/documents/PPI%20Header%20format%201.0.7.pdf">the
Per-Packet Information Header Specification</a>, followed by a packet
with the LINKTYPE_ value specified by the pph_dlt field of that header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IEEE802_15_4_WITHFCS</td>
<td class="number">195</td>
<td class="symbol">DLT_IEEE802_15_4_WITHFCS</td>
<td>
<a href="https://ieeexplore.ieee.org/document/7460875/">IEEE
802.15.4</a> Low-Rate Wireless Networks, with each packet having the FCS
at the end of the frame.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_SITA</td>
<td class="number">196</td>
<td class="symbol">DLT_SITA</td>
<td>
Various link-layer types, with
<a href="linktypes/LINKTYPE_SITA.html">a pseudo-header</a>,
for <a href="https://www.sita.aero">SITA</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_ERF</td>
<td class="number">197</td>
<td class="symbol">DLT_ERF</td>
<td>
Various link-layer types, with a pseudo-header, for Endace DAG cards;
encapsulates Endace ERF records.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_BLUETOOTH_HCI_H4_WITH_PHDR</td>
<td class="number">201</td>
<td class="symbol">DLT_BLUETOOTH_HCI_H4_WITH_PHDR</td>
<td>
Bluetooth HCI UART transport layer; the frame contains a 4-byte
direction field, in network byte order (big-endian), the low-order bit
of which is set if the frame was sent from the host to the controller
and clear if the frame was received by the host from the controller,
followed by an HCI packet indicator byte, as specified by the UART
Transport Layer portion of the most recent <a
href="https://web.archive.org/web/20130314201541/https://www.bluetooth.org/Technical/Specifications/adopted.htm">
Bluetooth Core specification</a>, followed by an HCI packet of the
specified packet type, as specified by the Host Controller Interface
Functional Specification portion of the most recent Bluetooth Core
Specification.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_AX25_KISS</td>
<td class="number">202</td>
<td class="symbol">DLT_AX25_KISS</td>
<td>
<a href="http://www.ax25.net/AX25.2.2-Jul%2098-2.pdf">AX.25</a> packet,
with a 1-byte <a href="http://www.ax25.net/kiss.aspx">KISS</a> header
containing a type indicator.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_LAPD</td>
<td class="number">203</td>
<td class="symbol">DLT_LAPD</td>
<td>
Link Access Procedures on the D Channel (LAPD) frames, as specified by
<a href="https://www.itu.int/rec/T-REC-Q.920/en">ITU-T
Recommendation Q.920</a>
and
<a href="https://www.itu.int/rec/T-REC-Q.921/en">ITU-T
Recommendation Q.921</a>, starting with the address field, with no
pseudo-header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_PPP_WITH_DIR</td>
<td class="number">204</td>
<td class="symbol">DLT_PPP_WITH_DIR</td>
<td>
PPP, as per
<a href="https://tools.ietf.org/html/rfc1661">RFC 1661</a>
and
<a href="https://tools.ietf.org/html/rfc1662">RFC 1662</a>,
preceded with a one-byte pseudo-header with a zero value meaning
"received by this host" and a non-zero value meaning "sent by this
host"; if the first 2 bytes are 0xff and 0x03, it's PPP in HDLC-like
framing, with the PPP header following those two bytes, otherwise it's
PPP without framing, and the packet begins with the PPP header. The
data in the frame is not octet-stuffed or bit-stuffed.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_C_HDLC_WITH_DIR</td>
<td class="number">205</td>
<td class="symbol">DLT_C_HDLC_WITH_DIR</td>
<td>
Cisco PPP with HDLC framing, as per
<a href="https://tools.ietf.org/html/rfc1547#section-4.3.1">
section 4.3.1 of RFC 1547</a>,
preceded with a one-byte pseudo-header with a zero value meaning
"received by this host" and a non-zero value meaning "sent by this
host".
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_FRELAY_WITH_DIR</td>
<td class="number">206</td>
<td class="symbol">DLT_FRELAY_WITH_DIR</td>
<td>
Frame Relay LAPF frames, beginning with a one-byte pseudo-header with a
zero value meaning "received by this host" (DCE->DTE) and a non-zero
value meaning "sent by this host" (DTE->DCE), followed by an <a
href="https://www.itu.int/rec/T-REC-Q.922/en/">ITU-T Recommendation
Q.922</a> LAPF header starting with the address field, and without an
FCS at the end of the frame.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_LAPB_WITH_DIR</td>
<td class="number">207</td>
<td class="symbol">DLT_LAPB_WITH_DIR</td>
<td>
Link Access Procedure, Balanced (LAPB), as specified by
<a href="https://www.itu.int/rec/T-REC-X.25/en">ITU-T
Recommendation X.25</a>, preceded with a one-byte pseudo-header with a
zero value meaning "received by this host" (DCE->DTE) and a non-zero
value meaning "sent by this host" (DTE->DCE).
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IPMB_LINUX</td>
<td class="number">209</td>
<td class="symbol">DLT_IPMB_LINUX</td>
<td>
<a href="https://www.intel.com/content/www/us/en/products/docs/servers/ipmi/ipmi-second-gen-interface-spec-v2-rev1-1.html">IPMB</a>
over an
<a href="https://www.nxp.com/docs/en/user-guide/UM10204.pdf">I2C</a>
circuit, with
<a href="linktypes/LINKTYPE_IPMB_LINUX.html">a Linux-specific
pseudo-header</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_FLEXRAY</td>
<td class="number">210</td>
<td class="symbol">DLT_FLEXRAY</td>
<td>
<a href="https://www.iso.org/standard/59806.html">FlexRay</a>
automotive bus frames or symbols, preceded by a
<a href="linktypes/LINKTYPE_FLEXRAY.html">pseudo-header</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IEEE802_15_4_NONASK_PHY</td>
<td class="number">215</td>
<td class="symbol">DLT_IEEE802_15_4_NONASK_PHY</td>
<td>
<a href="https://ieeexplore.ieee.org/document/7460875/">IEEE 802.15.4</a>
Low-Rate Wireless Networks, with each packet having the FCS at the end
of the frame, and with the PHY-level data for the O-QPSK, BPSK, GFSK,
MSK, and RCC DSS BPSK PHYs (4 octets of 0 as preamble, one octet of SFD,
one octet of frame length + reserved bit) preceding the MAC-layer data
(starting with the frame control field).
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_USB_LINUX_MMAPPED</td>
<td class="number">220</td>
<td class="symbol">DLT_USB_LINUX_MMAPPED</td>
<td>
USB packets, beginning with a Linux USB header, as specified by the
<tt>struct usbmon_packet</tt> in the
<tt>Documentation/usb/usbmon.txt</tt> file in the Linux source tree.
All 64 bytes of the header are present. All fields in the header are in
host byte order. When performing a live capture, the host byte order is
the byte order of the machine on which the packets are captured. When
reading a pcap file, the byte order is the byte order for the file, as
specified by the file's magic number; when reading a pcapng file, the
byte order is the byte order for the section of the pcapng file, as
specified by the Section Header Block. For isochronous transfers, the
<tt>ndesc</tt> field specifies the number of isochronous descriptors
that follow.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_FC_2</td>
<td class="number">224</td>
<td class="symbol">DLT_FC_2</td>
<td>
Fibre Channel FC-2 frames, beginning with a Frame_Header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_FC_2_WITH_FRAME_DELIMS</td>
<td class="number">225</td>
<td class="symbol">DLT_FC_2_WITH_FRAME_DELIMS</td>
<td>
Fibre Channel FC-2 frames, beginning an encoding of the SOF, followed by
a Frame_Header, and ending with an encoding of the SOF.
<p>
The encodings represent the frame delimiters as 4-byte sequences
representing the corresponding ordered sets, with K28.5 represented as
0xBC, and the D symbols as the corresponding byte values; for example,
SOFi2, which is K28.5 - D21.5 - D1.2 - D21.2, is represented as 0xBC
0xB5 0x55 0x55.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IPNET</td>
<td class="number">226</td>
<td class="symbol">DLT_IPNET</td>
<td>
<a href="linktypes/LINKTYPE_IPNET.html">Solaris ipnet pseudo-header</a>,
followed by an IPv4 or IPv6 datagram.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_CAN_SOCKETCAN</td>
<td class="number">227</td>
<td class="symbol">DLT_CAN_SOCKETCAN</td>
<td>
CAN (Controller Area Network) frames, with <a
href="linktypes/LINKTYPE_CAN_SOCKETCAN.html">a pseudo-header</a>
followed by the frame payload.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IPV4</td>
<td class="number">228</td>
<td class="symbol">DLT_IPV4</td>
<td>
Raw IPv4; the packet begins with an IPv4 header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IPV6</td>
<td class="number">229</td>
<td class="symbol">DLT_IPV6</td>
<td>
Raw IPv6; the packet begins with an IPv6 header.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_IEEE802_15_4_NOFCS</td>
<td class="number">230</td>
<td class="symbol">DLT_IEEE802_15_4_NOFCS</td>
<td>
<a href="https://ieeexplore.ieee.org/document/7460875/">IEEE 802.15.4</a>
Low-Rate Wireless Network, without the FCS at the end of the frame.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_DBUS</td>
<td class="number">231</td>
<td class="symbol">DLT_DBUS</td>
<td>
Raw <a href="http://www.freedesktop.org/wiki/Software/dbus">D-Bus</a>
<a href="https://dbus.freedesktop.org/doc/dbus-specification.html#message-protocol-messages">
messages</a>, starting with the endianness flag, followed by the message
type, etc., but without the
<a href="https://dbus.freedesktop.org/doc/dbus-specification.html#auth-protocol">
authentication handshake</a> before the message sequence.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_DVB_CI</td>
<td class="number">235</td>
<td class="symbol">DLT_DVB_CI</td>
<td>
DVB-CI (DVB Common Interface for communication between a PC Card module
and a DVB receiver), with the message format specified by
<a href="https://www.kaiser.cx/pcap-dvbci.html">the PCAP format for
DVB-CI specification</a>.
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_MUX27010</td>
<td class="number">236</td>
<td class="symbol">DLT_MUX27010</td>
<td>
<a href="linktypes/LINKTYPE_MUX27010.html">Variant of 3GPP TS 27.010
multiplexing protocol</a> (similar to, but <em>not</em> the same as,
27.010).
</td>
</tr>
<tr>
<td class="symbol">LINKTYPE_STANAG_5066_D_PDU</td>
<td class="number">237</td>
<td class="symbol">DLT_STANAG_5066_D_PDU</td>
<td>