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<title>Token Ring</title>

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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Token Ring</span></span>

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</header>

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<p><b>Token Ring</b> is a <a href="Physical_layer" title="Physical layer">physical</a> and <a href="Data_link_layer" title="Data link layer">data link layer</a> <a href="Computer_network" title="Computer network">computer networking</a> technology used to build <a href="Local_area_network" title="Local area network">local area networks</a>. It was introduced by <a href="IBM" title="IBM">IBM</a> in 1984, and standardized in 1989 as <b><a href="IEEE_Standards_Association" title="IEEE Standards Association">IEEE</a> 802.5</b>. It uses a special three-byte <a href="Frame_(networking)" title="Frame (networking)">frame</a> called a <i>token</i> that is passed around a logical <i>ring</i> of workstations or <a href="Server_(computing)" title="Server (computing)">servers</a>. This <a href="Token_passing" title="Token passing">token passing</a> is a <a href="Channel_access_method" title="Channel access method">channel access method</a> providing fair access for all stations, and eliminating the <a href="Collision_(telecommunications)" title="Collision (telecommunications)">collisions</a> of <a href="Contention_(telecommunications)" title="Contention (telecommunications)">contention</a>-based access methods.

</p><p>Following its introduction, Token Ring technology became widely adopted, particularly in corporate environments, but was gradually eclipsed by newer iterations of <a href="Ethernet" title="Ethernet">Ethernet</a>. The last formalized Token Ring standard that was completed was Gigabit Token Ring (IEEE 802.5z), published on May 4, 2001.<sup id="cite_ref-802.5-act_1-0" class="reference"><a href="#cite_note-802.5-act-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="History">History</h2></div>

<p>A wide range of different <a href="Local_area_network" title="Local area network">local area network</a> technologies were developed in the early 1970s, of which one, the <a href="Cambridge_Ring_(computer_network)" title="Cambridge Ring (computer network)">Cambridge Ring</a>, had demonstrated the potential of a <a href="Token_passing" title="Token passing">token passing</a> <a href="Ring_topology" class="mw-redirect" title="Ring topology">ring topology</a>, and many teams worldwide began working on their own implementations. At the <a href="IBM_Zurich_Research_Laboratory" class="mw-redirect" title="IBM Zurich Research Laboratory">IBM Zurich Research Laboratory</a> Werner Bux and Hans Müller, in particular, worked on the design and development of IBM's Token Ring technology,<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> while early work at <a href="MIT" class="mw-redirect" title="MIT">MIT</a><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> led to the <a href="Proteon" title="Proteon">Proteon</a> <span class="nowrap">10 Mbit/s</span> ProNet-10 Token Ring network in 1981<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup> – the same year that <a href="Workstation" title="Workstation">workstation</a> vendor <a href="Apollo_Computer" title="Apollo Computer">Apollo Computer</a> introduced their proprietary <span class="nowrap">12 Mbit/s</span> Apollo Token Ring (ATR) network running over 75-ohm <a href="RG-6U" class="mw-redirect" title="RG-6U">RG-6U</a> <a href="Coaxial_cabling" class="mw-redirect" title="Coaxial cabling">coaxial cabling</a>. Proteon later developed an upgraded <span class="nowrap">16 Mbit/s</span> version that ran on unshielded twisted pair cable.

</p>

<div class="mw-heading mw-heading3"><h3 id="1985_IBM_launch">1985 IBM launch</h3></div>

<p>IBM launched their own proprietary Token Ring product on October 15, 1985.<sup id="cite_ref-:0_5-0" class="reference"><a href="#cite_note-:0-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup> It ran at <span class="nowrap">4 Mbit/s</span>,<sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup> and attachment was possible from IBM PCs, midrange computers and mainframes. It used a convenient star-wired physical topology and ran over shielded twisted-pair cabling. Shortly thereafter it became the basis for the IEEE 802.5 standard.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup>

</p><p>During this time, IBM argued that Token Ring LANs were superior to <a href="Ethernet" title="Ethernet">Ethernet</a>, especially under load,<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup> but these claims were debated.<sup id="cite_ref-Boggs1988_10-0" class="reference"><a href="#cite_note-Boggs1988-10"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup>

</p><p>In 1988, the faster <span class="nowrap">16 Mbit/s</span> Token Ring was standardized by the 802.5 working group.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup> An increase to <span class="nowrap">100 Mbit/s</span> was standardized and marketed during the wane of Token Ring's existence and was never widely used.<sup id="cite_ref-redbooks.ibm.com_12-0" class="reference"><a href="#cite_note-redbooks.ibm.com-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> While a <span class="nowrap">1000 Mbit/s</span> standard was approved in 2001, no products were ever brought to market and standards activity came to a standstill<sup id="cite_ref-13" class="reference"><a href="#cite_note-13"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup> as <a href="Fast_Ethernet" title="Fast Ethernet">Fast Ethernet</a> and <a href="Gigabit_Ethernet" title="Gigabit Ethernet">Gigabit Ethernet</a> dominated the local area networking market.

</p>

<div class="mw-heading mw-heading3"><h3 id="Gallery">Gallery</h3></div>

<div class="gallerytext"><span class="nowrap">100 Mbit/s</span> IBM Token Ring Management Adapter with wake-on-LAN. Both UTP (RJ45) and STP (IBM Data Connector) interfaces are present.</div>

</li>

<div class="gallerytext">Assorted full-length Micro Channel Token Ring cards, including a LANStreamer which features multiple RJ45 ports for usage in a Token Ring network</div>

</li>

<div class="gallerytext">Token Ring Network Interface Cards (NICs) with varying interfaces from: ISA, PCI and <a href="Micro_Channel" class="mw-redirect" title="Micro Channel">Micro Channel</a></div>

</li>

<div class="gallerytext">Madge <span class="nowrap">4/16 Mbit/s</span> TokenRing ISA NIC</div>

</li>

<div class="gallerytext">A series of multiple 16/4 early Micro Channel Token Ring cards which would have predominantly been installed in many Personal System/2 machines</div>

</li>

<div class="gallerytext">Texas Instruments TMS380C26PQL network communication processor, used in a Hewlett Packard <a href="JetDirect" title="JetDirect">JetDirect</a> Token Ring print server card</div>

</li>

</ul>

<div class="mw-heading mw-heading2"><h2 id="Comparison_with_Ethernet">Comparison with Ethernet</h2></div>

<p>Early Ethernet and Token Ring both used a shared transmission medium. They differed in their <a href="Channel_access_method" title="Channel access method">channel access methods</a>. These differences have become immaterial, as modern Ethernet networks consist of switches and <a href="Point-to-point_link" class="mw-redirect" title="Point-to-point link">point-to-point links</a> operating in <a href="Full-duplex" class="mw-redirect" title="Full-duplex">full-duplex</a> mode.

</p><p>Token Ring and legacy Ethernet have some notable differences:

</p>

<ul><li>Token Ring access is more <a href="Deterministic_system" title="Deterministic system">deterministic</a>, compared to Ethernet's contention-based <a href="CSMA/CD" class="mw-redirect" title="CSMA/CD">CSMA/CD</a>.</li>

<li>Ethernet supports a direct cable connection between two network interface cards by the use of a <a href="Ethernet_crossover_cable" title="Ethernet crossover cable">crossover cable</a> or through <a href="Auto_MDI-X" class="mw-redirect" title="Auto MDI-X">auto-sensing</a> if supported. Token Ring does not inherently support this feature and requires additional software and hardware to operate on a direct cable connection setup.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup></li>

<li>Token Ring eliminates collision by the use of a single-use token and early token release to alleviate the down time. Legacy Ethernet alleviates collision by <a href="Carrier-sense_multiple_access" title="Carrier-sense multiple access">carrier-sense multiple access</a> and by the use of an intelligent <a href="Network_switch" title="Network switch">switch</a>; primitive Ethernet devices like <a href="Ethernet_hub" title="Ethernet hub">hubs</a> could precipitate collisions due to repeating traffic blindly.<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup></li>

<li>Token Ring network interface cards contain all of the intelligence required for speed autodetection, routing and can drive themselves on many Multistation Access Units (MAUs) that operate without power (most MAUs operate in this fashion, only requiring a power supply for <a href="LED" class="mw-redirect" title="LED">LEDs</a>). Ethernet network interface cards can theoretically operate on a passive hub to a degree, but not as a large LAN and the issue of collisions is still present.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup></li>

<li>Token Ring employs <i>access priority</i> in which certain nodes can have priority over the token. Unswitched Ethernet did not have a provision for an access priority system as all nodes have equal access to the <a href="Transmission_medium" title="Transmission medium">transmission medium</a>.</li>

<li>Multiple identical <a href="MAC_address" title="MAC address">MAC addresses</a> are supported on Token Ring (a feature used by <a href="S/390" class="mw-redirect" title="S/390">S/390</a> mainframes).<sup id="cite_ref-redbooks.ibm.com_12-1" class="reference"><a href="#cite_note-redbooks.ibm.com-12"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> Switched Ethernet cannot support duplicate MAC addresses without reprimand.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup></li>

<li>Token Ring was more complex than Ethernet, requiring a specialized processor and licensed MAC/<a href="Logical_link_control" title="Logical link control">LLC</a> firmware for each interface. By contrast, Ethernet included both the (simpler) firmware and the lower licensing cost in the MAC chip. The cost of a token Ring interface using the Texas Instruments TMS380C16 MAC and PHY was approximately three times that of an Ethernet interface using the Intel 82586 MAC and PHY.</li>

<li>Initially both networks used expensive cable, but once Ethernet was standardized for unshielded <a href="Ethernet_over_twisted_pair" title="Ethernet over twisted pair">twisted pair</a> with <a href="10BASE-T" class="mw-redirect" title="10BASE-T">10BASE-T</a> (<a href="Category_3_cable" title="Category 3 cable">Cat 3</a>) and <a href="100BASE-TX" class="mw-redirect" title="100BASE-TX">100BASE-TX</a> (<a href="Category_5_cable" title="Category 5 cable">Cat 5(e)</a>), it had a distinct advantage and sales of it increased markedly.</li>

<li>Even more significant when comparing overall system costs was the much-higher cost of router ports and network cards for Token Ring vs Ethernet. The emergence of Ethernet switches may have been the final straw.</li></ul>

<div class="mw-heading mw-heading2"><h2 id="Operation">Operation</h2></div>

<p>Stations on a Token Ring LAN are <a href="Logical_topology" class="mw-redirect" title="Logical topology">logically organized</a> in a <a href="Ring_topology" class="mw-redirect" title="Ring topology">ring topology</a> with data being transmitted sequentially from one ring station to the next with a control token circulating around the ring controlling access. Similar <a href="Token_passing" title="Token passing">token passing</a> mechanisms are used by <a href="ARCNET" title="ARCNET">ARCNET</a>, <a href="Token_bus" class="mw-redirect" title="Token bus">token bus</a>, <a href="100VG-AnyLAN" class="mw-redirect" title="100VG-AnyLAN">100VG-AnyLAN</a> (802.12) and <a href="FDDI" class="mw-redirect" title="FDDI">FDDI</a>, and they have theoretical advantages over the <a href="CSMA/CD" class="mw-redirect" title="CSMA/CD">CSMA/CD</a> of early Ethernet.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading3"><h3 id="Access_control">Access control</h3></div>

<p>The data transmission process goes as follows:

</p>

<ul><li>Empty information frames are continuously circulated on the ring.</li>

<li>When a computer has a message to send, it seizes the token. The computer will then be able to send the frame.</li>

<li>The frame is then examined by each successive workstation. The workstation that identifies itself to be the destination for the message copies it from the frame and changes the token back to 0.</li>

<li>When the frame gets back to the originator, it sees that the token has been changed to 0 and that the message has been copied and received. It removes the message from the frame.</li>

<li>The frame continues to circulate as an <i>empty</i> frame, ready to be taken by a workstation when it has a message to send.</li></ul>

<div class="mw-heading mw-heading3"><h3 id="Multistation_Access_Units_and_Controlled_Access_Units">Multistation Access Units and Controlled Access Units</h3></div>

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</style><div role="note" class="hatnote navigation-not-searchable">Main article: <a href="Media_Access_Unit" class="mw-redirect" title="Media Access Unit">Media Access Unit</a></div>

<p>Physically, a Token Ring network is wired as a <a href="Star_network" title="Star network">star</a>, with 'MAUs' in the center, 'arms' out to each station, and the loop going out-and-back through each.<sup id="cite_ref-ReferenceA_19-0" class="reference"><a href="#cite_note-ReferenceA-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup>

</p><p>A MAU could present in the form of a hub or a switch; since Token Ring had no collisions many MAUs were manufactured as hubs. Although Token Ring runs on <a href="Logical_link_control" title="Logical link control">LLC</a>, it includes source routing to forward packets beyond the local network. The majority of MAUs are configured in a 'concentration' configuration by default, but later MAUs also supporting a feature to act as splitters and not concentrators exclusively such as on the IBM 8226.<sup id="cite_ref-20" class="reference"><a href="#cite_note-20"><span class="cite-bracket">[</span>20<span class="cite-bracket">]</span></a></sup>

</p>

<p>Later IBM would release Controlled Access Units that could support multiple MAU modules known as a Lobe Attachment Module. The CAUs supported features such as Dual-Ring Redundancy for alternate routing in the event of a dead port, modular concentration with LAMs, and multiple interfaces like most later MAUs.<sup id="cite_ref-21" class="reference"><a href="#cite_note-21"><span class="cite-bracket">[</span>21<span class="cite-bracket">]</span></a></sup> This offered a more reliable setup and remote management than with an unmanaged MAU hub.

</p>

<div class="mw-heading mw-heading3"><h3 id="Cabling_and_interfaces">Cabling and interfaces</h3></div>

<p>Cabling is generally IBM "Type-1", a heavy two-pair 150 ohm <a href="Twisted_pair" title="Twisted pair">shielded twisted pair</a> cable. This was the basic cable for the "IBM Cabling System", a <a href="Structured_cabling" title="Structured cabling">structured cabling</a> system that IBM hoped would be widely adopted. Unique <a href="Hermaphroditic_connector" class="mw-redirect" title="Hermaphroditic connector">hermaphroditic connectors</a>, referred to as <b>IBM Data Connectors</b> in formal writing or colloquially as <a href="Boy_George" title="Boy George">Boy George</a> connectors, were used.<sup id="cite_ref-22" class="reference"><a href="#cite_note-22"><span class="cite-bracket">[</span>22<span class="cite-bracket">]</span></a></sup> The connectors have the disadvantage of being quite bulky, requiring at least 3 cm × 3 cm (1.2 in × 1.2 in) panel space, and being relatively fragile. The advantages of the connectors being that they are genderless and have superior shielding over standard unshielded 8P8C. Connectors at the computer were usually <a href="D-subminiature" title="D-subminiature">DE-9</a> female. Several other types of cable existed such as type 2, and type 3 cable.<sup id="cite_ref-23" class="reference"><a href="#cite_note-23"><span class="cite-bracket">[</span>23<span class="cite-bracket">]</span></a></sup>

</p><p>In later implementations of Token Ring, <a href="Category_4_cable" title="Category 4 cable">Cat 4</a> cabling was also supported, so <a href="8P8C" class="mw-redirect" title="8P8C">8P8C</a> (RJ45) connectors were used on both of the MAUs, CAUs and NICs; with many of the network cards supporting both 8P8C and DE-9 for backwards compatibility.<sup id="cite_ref-ReferenceA_19-1" class="reference"><a href="#cite_note-ReferenceA-19"><span class="cite-bracket">[</span>19<span class="cite-bracket">]</span></a></sup>

</p>

<div class="gallerytext">IBM Data Connectors on the IBM 8228 Multistation Access Unit</div>

</li>

<div class="gallerytext">8P8C 'Media Filters' that plug into an IBM Data Connector converting it for use with 8P8C connectors</div>

</li>

</ul>

<div class="mw-heading mw-heading2"><h2 id="Technical_details">Technical details</h2></div>

<div class="mw-heading mw-heading3"><h3 id="Frame_types">Frame types</h3></div>

<div class="mw-heading mw-heading4"><h4 id="Token">Token</h4></div>

<p>When no station is sending a frame, a special token frame circles the loop. This special token frame is repeated from station to station until arriving at a station that needs to send data.

</p><p>Tokens are three octets in length and consist of a start delimiter, an access control octet, and an end delimiter.

</p>

<th>Start Delimiter

</th>

<th>Access Control

</th>

<th>End Delimiter

</th></tr>

<tr>

<td>8 bits

</td>

<td>8 bits

</td>

<td>8 bits

</td></tr></tbody></table>

<div class="mw-heading mw-heading4"><h4 id="Abort_frame">Abort frame</h4></div>

<p>Used by the sending station to abort transmission.

</p>

<th>SD

</th>

<th>ED

</th></tr>

<tr>

<td>8 bits

</td>

<td>8 bits

</td></tr></tbody></table>

<p>Data frames carry information for upper-layer protocols, while command frames contain control information and have no

data for upper-layer protocols. Data and command frames vary in size, depending on the size of the Information field.

</p>

<th>SD

</th>

<th>AC

</th>

<th>FC

</th>

<th>DA

</th>

<th>SA

</th>

<th>PDU from LLC (IEEE 802.2)

</th>

<th>CRC

</th>

<th>ED

</th>

<th>FS

</th></tr>

<tr>

<td>8 bits

</td>

<td>8 bits

</td>

<td>8 bits

</td>

<td>48 bits

</td>

<td>48 bits

</td>

<td>Up to 4500 × 8 bits

</td>

<td>32 bits

</td>

<td>8 bits

</td>

<td>8 bits

</td></tr></tbody></table>

<dl><dt>Starting delimiter</dt>

<dd>The starting delimiter consists of a special bit pattern denoting the beginning of the frame. The bits from most significant to least significant are J,K,0,J,K,0,0,0. J and K are code violations of <a href="Differential_Manchester_encoding" title="Differential Manchester encoding">Differential Manchester encoding</a>. Differential Manchester encoding has a mid symbol transition for every coded 0 or 1, however the J and K codes do not have a mid symbol transition. Both the Starting Delimiter and Ending Delimiter fields are used to mark frame boundaries.</dd></dl>

<th>J

</th>

<th>K

</th>

<th>0

</th>

<th>J

</th>

<th>K

</th>

<th>0

</th>

<th>0

</th>

<th>0

</th></tr>

<tr>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td></tr></tbody></table></dd></dl>

<dl><dt>Access control</dt>

<dd>This byte field consists of the following bits from most significant to least significant bit order: P,P,P,T,M,R,R,R. The P bits are priority bits, T is the token bit which when set specifies that this is a token frame, M is the monitor bit which is set by the Active Monitor (AM) station when it sees this frame, and R bits are reservation bits, which indicate that the next token should be issued with that priority.</dd></dl>

<th style="width:4%;">+

</th>

<th colspan="4" style="width:37.5%;">Bits 0–2

</th>

<th colspan="4" style="width:12.5%;">3

</th>

<th colspan="8" style="width:37.5%;">4

</th>

<th colspan="3" style="width:12.5%;">5–7

</th></tr>

<tr>

<th>0

</th>

<td colspan="4">Priority

</td>

<td colspan="4">Token

</td>

<td colspan="8">Monitor

</td>

<td colspan="16">Reservation

</td></tr></tbody></table></dd></dl>

<dl><dt>Frame control</dt>

<dd>A one-byte field that contains bits describing the data portion of the frame contents which indicates whether the frame contains data or control information. In control frames, this byte specifies the type of control information.</dd></dl>

<th style="width:4%;">+

</th>

<th colspan="4" style="width:25%;">Bits 0–1

</th>

<th colspan="4" style="width:75%;">Bits 2–7

</th></tr>

<tr>

<th>0

</th>

<td colspan="4">Frame type

</td>

<td colspan="4">Control Bits

</td></tr></tbody></table></dd></dl>

<dl><dd>Frame type – <b>01</b> indicates LLC frame IEEE 802.2 (data) and ignore control bits;</dd>

<dd><b>00</b> indicates MAC frame and control bits indicate the type of <a href="Medium_access_control" title="Medium access control">MAC</a> control frame</dd></dl>

<dl><dt>Destination address</dt>

<dd>A six-byte field used to specify the destination(s) physical address.</dd>

<dt>Source address</dt>

<dd>Contains physical address of sending station. It is a six-byte field that is either the local assigned address (LAA) or universally assigned address (UAA) of the sending station adapter.</dd>

<dd>A variable length field of 0 or more bytes, the maximum allowable size depending on ring speed containing MAC management data or upper layer information. Maximum length of 4500 bytes.</dd>

<dt>Frame check sequence</dt>

<dd>A four-byte field used to store the calculation of a CRC for frame integrity verification by the receiver.</dd>

<dt>Ending delimiter</dt>

<dd>The counterpart to the starting delimiter, this field marks the end of the frame and consists of the following bits from most significant to least significant: J,K,1,J,K,1,I,E. I is the intermediate frame bit and E is the error bit.</dd></dl>

<th>J

</th>

<th>K

</th>

<th>1

</th>

<th>J

</th>

<th>K

</th>

<th>1

</th>

<th>I

</th>

<th>E

</th></tr>

<tr>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td></tr></tbody></table></dd></dl>

<dl><dt>Frame status</dt>

<dd>A one-byte field used as a primitive acknowledgment scheme on whether the frame was recognized and copied by its intended receiver.</dd></dl>

<th>A

</th>

<th>C

</th>

<th>0

</th>

<th>0

</th>

<th>A

</th>

<th>C

</th>

<th>0

</th>

<th>0

</th></tr>

<tr>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td>

<td>1 bit

</td></tr></tbody></table></dd></dl>

<dl><dd><b>A</b> = 1, Address recognized</dd>

<dd><b>C</b> = 1, Frame copied</dd></dl>

<div class="mw-heading mw-heading3"><h3 id="Active_and_standby_monitors">Active and standby monitors</h3></div>

<p>Every station in a Token Ring network is either an active monitor (AM) or standby monitor (SM) station. There can be only one active monitor on a ring at a time. The active monitor is chosen through an election or <i>monitor contention</i> process.

</p><p>The monitor contention process is initiated when the following happens:

</p>

<ul><li>a loss of signal on the ring is detected.</li>

<li>an active monitor station is not detected by other stations on the ring.</li>

<li>a particular timer on an end station expires such as the case when a station hasn't seen a token frame in the past 7 seconds.</li></ul>

<p>When any of the above conditions take place and a station decides that a new monitor is needed, it will transmit a <i>claim token</i> frame, announcing that it wants to become the new monitor. If that token returns to the sender, it is OK for it to become the monitor. If some other station tries to become the monitor at the same time then the station with the highest <a href="MAC_address" title="MAC address">MAC address</a> will win the election process. Every other station becomes a standby monitor. All stations must be capable of becoming an active monitor station if necessary.

</p><p>The active monitor performs a number of ring administration functions. The first function is to operate as the master clock for the ring in order to provide synchronization of the signal for stations on the wire. Another function of the AM is to insert a 24-bit delay into the ring, to ensure that there is always sufficient buffering in the ring for the token to circulate. A third function for the AM is to ensure that exactly one token circulates whenever there is no frame being transmitted, and to detect a broken ring. Lastly, the AM is responsible for removing circulating frames from the ring.

</p>

<div class="mw-heading mw-heading3"><h3 id="Token_insertion_process">Token insertion process</h3></div>

<p>Token Ring stations must go through a 5-phase ring insertion process before being allowed to participate in the ring network. If any of these phases fail, the Token Ring station will not <i>insert</i> into the ring and the Token Ring driver may report an error.

</p>

<ul><li>Phase 0 (Lobe Check) – A station first performs a lobe media check. A station is <i>wrapped</i> at the MSAU and is able to send 2000 test frames down its transmit pair which will loop back to its receive pair. The station checks to ensure it can receive these frames without error.</li>

<li>Phase 1 (Physical Insertion) – A station then sends a 5-volt signal to the MSAU to open the relay.</li>

<li>Phase 2 (Address Verification) – A station then transmits MAC frames with its own MAC address in the destination address field of a Token Ring frame. When the frame returns and if the Address Recognized (AR) and Frame Copied (FC) bits in the frame-status are set to 0 (indicating that no other station currently on the ring uses that address), the station must participate in the periodic (every 7 seconds) ring poll process. This is where stations identify themselves on the network as part of the MAC management functions.</li>

<li>Phase 3 (Participation in ring poll) – A station learns the address of its Nearest Active Upstream Neighbour (NAUN) and makes its address known to its nearest downstream neighbour, leading to the creation of the ring map. Station waits until it receives an AMP or SMP frame with the AR and FC bits set to 0. When it does, the station flips both bits (AR and FC) to 1, if enough resources are available, and queues an SMP frame for transmission. If no such frames are received within 18 seconds, then the station reports a failure to open and de-inserts from the ring. If the station successfully participates in a ring poll, it proceeds into the final phase of insertion, request initialization.</li>

<li>Phase 4 (Request Initialization) – Finally a station sends out a special request to a parameter server to obtain configuration information. This frame is sent to a special functional address, typically a Token Ring bridge, which may hold timer and ring number information the new station needs to know.</li></ul>

<div class="mw-heading mw-heading3"><h3 id="Optional_priority_scheme">Optional priority scheme</h3></div>

<p>In some applications there is an advantage to being able to designate one station having a higher priority. Token Ring specifies an optional scheme of this sort, as does the <a href="CAN_Bus" class="mw-redirect" title="CAN Bus">CAN Bus</a>, (widely used in automotive applications) – but Ethernet does not.

</p><p>In the Token Ring priority MAC, eight priority levels, 0–7, are used. When the station wishing to transmit receives a token or data frame with a priority less than or equal to the station's requested priority, it sets the priority bits to its desired priority. The station does not immediately transmit; the token circulates around the medium until it returns to the station. Upon sending and receiving its own data frame, the station downgrades the token priority back to the original priority.

</p><p>Here are the following eight access priority and traffic types for devices that support <a href="802.1Q" class="mw-redirect" title="802.1Q">802.1Q</a> and <a href="802.1p" class="mw-redirect" title="802.1p">802.1p</a>:

</p>

<th>Priority bits</th>

<th>Traffic type

</th></tr>

<tr>

<td>x'000'

</td>

<td>Normal data traffic

</td></tr>

<tr>

<td>x'001'

</td>

<td>Not used

</td></tr>

<tr>

<td>x'010'

</td>

<td>Not used

</td></tr>

<tr>

<td>x'011'

</td>

<td>Not used

</td></tr>

<tr>

<td>x'100'

</td>

<td>Normal data traffic (forwarded from other devices)

</td></tr>

<tr>

<td>x'101'

</td>

<td>Data sent with time sensitivity requirements

</td></tr>

<tr>

<td>x'110'

</td>

<td>Data with real time sensitivity (i.e. VoIP)

</td></tr>

<tr>

<td>x'111'

</td>

<td>Station management

</td></tr></tbody></table>

<div class="mw-heading mw-heading2"><h2 id="Interconnection_with_Ethernet">Interconnection with Ethernet</h2></div>

<p>Bridging solutions for Token Ring and Ethernet networks included the AT&T StarWAN 10:4 Bridge,<sup id="cite_ref-network-world-page-56_24-0" class="reference"><a href="#cite_note-network-world-page-56-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> the IBM 8209 LAN Bridge<sup id="cite_ref-network-world-page-56_24-1" class="reference"><a href="#cite_note-network-world-page-56-24"><span class="cite-bracket">[</span>24<span class="cite-bracket">]</span></a></sup> and the Microcom LAN Bridge. Alternative connection solutions incorporated a router that could be configured to dynamically filter traffic, protocols and interfaces, such as the IBM 2210-24M Multiprotocol Router, which contained both Ethernet and Token Ring interfaces.<sup id="cite_ref-25" class="reference"><a href="#cite_note-25"><span class="cite-bracket">[</span>25<span class="cite-bracket">]</span></a></sup>

</p>

<div class="mw-heading mw-heading2"><h2 id="Operating_system_support">Operating system support</h2></div>

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<p>In 2012, <a href="David_S._Miller" title="David S. Miller">David S. Miller</a> merged a patch to remove token ring networking support from the <a href="Linux_kernel" title="Linux kernel">Linux kernel</a>.<sup id="cite_ref-26" class="reference"><a href="#cite_note-26"><span class="cite-bracket">[</span>26<span class="cite-bracket">]</span></a></sup>

</p>

<ul><li><a href="IBM_PC_Network" title="IBM PC Network">IBM PC Network</a></li>

<li><a href="Protocol_Wars" title="Protocol Wars">Protocol Wars</a> - The battle between Internet and OSI standards in the 1980s</li></ul>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

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.mw-parser-output cite.citation{font-style:inherit;word-wrap:break-word}.mw-parser-output .citation q{quotes:"\"""\"""'""'"}.mw-parser-output .citation:target{background-color:rgba(0,127,255,0.133)}.mw-parser-output .id-lock-free.id-lock-free a{background:url("./mw/Lock-green.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-limited.id-lock-limited a,.mw-parser-output .id-lock-registration.id-lock-registration a{background:url("./mw/Lock-gray-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .id-lock-subscription.id-lock-subscription a{background:url("./mw/Lock-red-alt-2.svg")right 0.1em center/9px no-repeat}.mw-parser-output .cs1-ws-icon a{background:url("./mw/Wikisource-logo.svg")right 0.1em center/12px no-repeat}body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-free a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-limited a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-registration a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .id-lock-subscription a,body:not(.skin-timeless):not(.skin-minerva) .mw-parser-output .cs1-ws-icon a{background-size:contain;padding:0 1em 0 0}.mw-parser-output .cs1-code{color:inherit;background:inherit;border:none;padding:inherit}.mw-parser-output .cs1-hidden-error{display:none;color:var(--color-error,#d33)}.mw-parser-output .cs1-visible-error{color:var(--color-error,#d33)}.mw-parser-output .cs1-maint{display:none;color:#085;margin-left:0.3em}.mw-parser-output .cs1-kern-left{padding-left:0.2em}.mw-parser-output .cs1-kern-right{padding-right:0.2em}.mw-parser-output .citation .mw-selflink{font-weight:inherit}@media screen{.mw-parser-output .cs1-format{font-size:95%}html.skin-theme-clientpref-night .mw-parser-output .cs1-maint{color:#18911f}}@media screen and (prefers-color-scheme:dark){html.skin-theme-clientpref-os .mw-parser-output .cs1-maint{color:#18911f}}

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<li id="cite_note-ReferenceA-19"><span class="mw-cite-backlink">^ <a href="#cite_ref-ReferenceA_19-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-ReferenceA_19-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20200616170856/ftp://ps-2.kev009.com/incoming/timc/PDFS/IBM/Networking/IBM_C_TR.pdf">"Why buy from IBM?"</a> <span class="cs1-format">(PDF)</span>. <a href="IBM" title="IBM">IBM</a>. Archived from <a rel="nofollow" class="external text" href="ftp://ps-2.kev009.com/incoming/timc/PDFS/IBM/Networking/IBM_C_TR.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2020-06-16<span class="reference-accessdate">. Retrieved <span class="nowrap">2016-08-03</span></span>.</cite></span>

</li>

<li id="cite_note-20"><span class="mw-cite-backlink"><b><a href="#cite_ref-20">^</a></b></span> <span class="reference-text"><cite id="CITEREFLouis_Ohland" class="citation web cs1">Louis Ohland. <a rel="nofollow" class="external text" href="https://ardent-tool.com/8226/">"8226 TR RJ45 Connection /Model 001"</a>. <i>Ardent Tool of Capitalism</i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-05-09</span></span>.</cite></span>

</li>

<li id="cite_note-21"><span class="mw-cite-backlink"><b><a href="#cite_ref-21">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20200616164253/http://public.dhe.ibm.com/networking/nswww/neteam/998pg/c823003.pdf">"IBM 8230 Controlled access Unit"</a> <span class="cs1-format">(PDF)</span>. <i>Public.dhe.ibm.com</i>. Archived from <a rel="nofollow" class="external text" href="http://public.dhe.ibm.com/networking/nswww/neteam/998pg/c823003.pdf">the original</a> <span class="cs1-format">(PDF)</span> on 2020-06-16<span class="reference-accessdate">. Retrieved <span class="nowrap">2016-08-03</span></span>.</cite></span>

</li>

<li id="cite_note-22"><span class="mw-cite-backlink"><b><a href="#cite_ref-22">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://web.archive.org/web/20130801102601/http://www.scottsnetworkclass.com/Ether_Token/Token_3.html">"Local Area Networks - Token Ring"</a>. Scottsnetworkclass.com. Archived from <a rel="nofollow" class="external text" href="http://www.scottsnetworkclass.com/Ether_Token/Token_3.html">the original</a> on 2013-08-01<span class="reference-accessdate">. Retrieved <span class="nowrap">2013-06-15</span></span>.</cite></span>

</li>

<li id="cite_note-23"><span class="mw-cite-backlink"><b><a href="#cite_ref-23">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://books.google.com/books?id=IRIEAAAAMBAJ&dq=type+3+token+ring&pg=PA38">"Network World"</a>. 25 April 1988.</cite></span>

</li>

<li id="cite_note-network-world-page-56-24"><span class="mw-cite-backlink">^ <a href="#cite_ref-network-world-page-56_24-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-network-world-page-56_24-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFMier1991" class="citation magazine cs1">Mier, Edwin (1991-06-03). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=wRIEAAAAMBAJ&pg=PA56">"Buying Smart"</a>. <i><a href="Network_World" class="mw-redirect" title="Network World">Network World</a></i>. Vol. 8, no. 21. IDG Network World Inc. p. 56<span class="reference-accessdate">. Retrieved <span class="nowrap">2016-08-03</span></span>.</cite></span>

</li>

<li id="cite_note-25"><span class="mw-cite-backlink"><b><a href="#cite_ref-25">^</a></b></span> <span class="reference-text"><cite class="citation book cs1"><a rel="nofollow" class="external text" href="http://ps-2.kev009.com/basil.holloway/ALL%20PDF/sg244446.pdf"><i>IBM 2210 Nways Multiprotocol Router Description and Configuration Scenarios - Volume I</i></a> <span class="cs1-format">(PDF)</span> (Third ed.). <a href="IBM" title="IBM">IBM</a> International Technical Support Organization Raleigh Center. June 1997. SG24-4446-02<span class="reference-accessdate">. Retrieved <span class="nowrap">2016-08-03</span></span>.</cite></span>

</li>

<li id="cite_note-26"><span class="mw-cite-backlink"><b><a href="#cite_ref-26">^</a></b></span> <span class="reference-text"><cite id="CITEREFCorbet" class="citation web cs1">Corbet, Jonathan. <a rel="nofollow" class="external text" href="https://lwn.net/Articles/497397/">"The end of the token ring era?"</a>. <i><a href="LWN.net" title="LWN.net">LWN.net</a></i><span class="reference-accessdate">. Retrieved <span class="nowrap">2023-09-22</span></span>.</cite></span>

</li>

</ol></div></div>

<div class="mw-heading mw-heading3"><h3 id="General">General</h3></div>

<ul><li><cite id="CITEREFCastelli2002" class="citation book cs1">Castelli, Matthew (2002). <i>Network Consultants Handbook</i>. Cisco Press. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-58705-039-8</bdi>.</cite></li>

<li><cite id="CITEREFGalloHancock,_William_M.2001" class="citation book cs1">Gallo, Michael; Hancock, William M. (2001). <i>Networking Explained</i>. Digital Press. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-55558-252-4</bdi>.</cite></li></ul>

<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>

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<div class="side-box-text plainlist">Wikimedia Commons has media related to <span style="font-weight: bold; font-style: italic;"><a href="https://commons.wikimedia.org/wiki/Category:Token_ring" class="extiw external" title="commons:Category:Token ring">Token ring</a></span>.</div></div>

</div>

<li><a rel="nofollow" class="external text" href="http://www.cisco.com/en/US/products/hw/modules/ps2643/products_tech_note09186a0080093dc2.shtml#first">Troubleshooting Cisco Router Token Ring Interfaces</a></li>

<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20120508172555/http://futureobservatory.dyndns.org/9056.htm">Futureobservatory.org discussion of IBM's failure in Token Ring technology</a></li>

<li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20140719220750/http://www.networkworld.com/article/2161208/lan-wan/what-if-ethernet-failed-.html">What if Ethernet had failed?</a></li></ul>

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</style><div id="Channel_access_methods_and_media_access_control194" style="font-size:114%;margin:0 4em"><a href="Channel_access_method" title="Channel access method">Channel access methods</a> and <a href="Medium_access_control" title="Medium access control">media access control</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Circuit_switching" title="Circuit switching">Channel-based</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Frequency-division_multiple_access" title="Frequency-division multiple access">FDMA</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Orthogonal_frequency-division_multiple_access" title="Orthogonal frequency-division multiple access">OFDMA</a></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Time-division_multiple_access" title="Time-division multiple access">TDMA</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<li><a href="Self-organized_time-division_multiple_access" title="Self-organized time-division multiple access">STDMA</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Code-division_multiple_access" title="Code-division multiple access">CDMA</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<li><a href="TD-SCDMA" class="mw-redirect" title="TD-SCDMA">TD-SCDMA</a></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Space-division_multiple_access" title="Space-division multiple access">SDMA</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Polarization-division_multiple_access" title="Polarization-division multiple access">PDMA</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Pulse-address_multiple_access" title="Pulse-address multiple access">PAMA</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Packet_switching" title="Packet switching">Packet-based</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Contention_(telecommunications)" title="Contention (telecommunications)">Collision recovery</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="ALOHAnet#The_ALOHA_protocol" title="ALOHAnet">ALOHA</a></li>

<li><a href="ALOHAnet" title="ALOHAnet">Slotted ALOHA</a></li>

<li><a href="Reservation_ALOHA" class="mw-redirect" title="Reservation ALOHA">R-ALOHA</a></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Contention_(telecommunications)" title="Contention (telecommunications)">Collision avoidance</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<li><a href="Multiple_Access_with_Collision_Avoidance_for_Wireless" title="Multiple Access with Collision Avoidance for Wireless">MACAW</a></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Collision_domain" title="Collision domain">Collision-free</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul>

<li><a href="Token_bus_network" title="Token bus network">Token bus</a></li>

<li><a href="Mobile_Slotted_Aloha" title="Mobile Slotted Aloha">MS-ALOHA</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Delay and disruption tolerant</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Mobile_ad_hoc_network" class="mw-redirect" title="Mobile ad hoc network">MANET</a></li>

<li><a href="Vehicular_ad-hoc_network" class="mw-redirect" title="Vehicular ad-hoc network">VANET</a></li>

<li><a href="Dynamic_Source_Routing" title="Dynamic Source Routing">Dynamic Source Routing</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Duplex_(telecommunications)" title="Duplex (telecommunications)">Duplexing methods</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

</div></td></tr></tbody></table></div>

<div class="navbox-styles"></div><div role="navigation" class="navbox" aria-labelledby="IEEE_standards209" style="padding:3px"><table class="nowraplinks hlist mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="IEEE_standards209" style="font-size:114%;margin:0 4em"><a href="IEEE_Standards_Association" title="IEEE Standards Association">IEEE standards</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%">Current</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="IEEE_754-2008_revision" title="IEEE 754-2008 revision">Revision</a></li></ul></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="IEEE_802" title="IEEE 802">802 series</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="IEEE_802" title="IEEE 802">802</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="WiMAX" title="WiMAX">WiMAX · d · e</a></li></ul></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="IEEE_802.1" title="IEEE 802.1">802.1</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="IEEE_802.3" title="IEEE 802.3">802.3</a> <br>(<a href="Ethernet" title="Ethernet">Ethernet</a>)</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="IEEE_802.11" title="IEEE 802.11">802.11</a> <br>(<a href="Wi-Fi" title="Wi-Fi">Wi-Fi</a>)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<li><a href="IEEE_802.11_(legacy_mode)" title="IEEE 802.11 (legacy mode)">legacy mode</a></li>

<li><a href="IEEE_802.11ad" title="IEEE 802.11ad">ad</a> (<a href="WiGig" title="WiGig">WiGig</a>)</li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="IEEE_802.15" title="IEEE 802.15">802.15</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="IEEE_802.15.1" class="mw-redirect" title="IEEE 802.15.1">.1</a> (<a href="Bluetooth" title="Bluetooth">Bluetooth</a>)</li>

<li><a href="IEEE_802.15.4" title="IEEE 802.15.4">.4</a> (<a href="Zigbee" title="Zigbee">Zigbee</a>)</li>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Proposed</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Superseded</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

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