Token-Ring local area network (LAN) technology was developed and promoted by IBM in the early 1980s and standardised as IEEE 802.5 by the Institute of Electrical and Electronics Engineers. Initially very successful, it went into steep decline after the introduction of 10BASE-T for Ethernet and the EIA/TIA 568 cabling standard in the early 1990s. A fierce marketing effort led by IBM sought to claim better performance and reliability over Ethernet for critical applications due to its deterministic access method, but was no more successful than similar battles in the same era over their Micro Channel architecture. IBM no longer uses or promotes Token-Ring. Madge Networks, a one time competitor to IBM, is now considered to be the market leader in Token Ring. The internet protocol suite is the set of communications protocols that implement the protocol stack on which the Internet and most commercial networks run. ... Bold text TBold texthe application layer is the seventh level of the seven-layer OSI model. ... It has been suggested that Domain name be merged into this article or section. ... Secure Sockets Layer (SSL) and Transport Layer Security (TLS), its successor, are cryptographic protocols which provide secure communications on the Internet. ... Trivial File Transfer Protocol (TFTP) is a very simple file transfer protocol, with the functionality of a very basic form of FTP; it was first defined in 1980. ... FTP or file transfer protocol is a commonly used protocol for exchanging files over any network that supports the TCP/IP protocol (such as the Internet or an intranet). ... HyperText Transfer Protocol (HTTP) is the method used to transfer or convey information on the World Wide Web. ... The Internet Message Access Protocol (commonly known as IMAP4, and previously called Internet Mail Access Protocol) is an application layer Internet protocol that allows a local client to access e-mail on a remote server. ... Internet Relay Chat (IRC) is a form of instant communication over the Internet. ... The Network News Transfer Protocol or NNTP is an Internet application protocol used primarily for reading and posting Usenet articles, as well as transferring news among news servers. ... In computing, local e-mail clients use the Post Office Protocol version 3 (POP3), an application-layer Internet standard protocol, to retrieve e-mail from a remote server over a TCP/IP connection. ... Session Initiation Protocol (SIP) is a protocol developed by the IETF MMUSIC Working Group and proposed standard for initiating, modifying, and terminating an interactive user session that involves multimedia elements such as video, voice, instant messaging, online games, and virtual reality. ... Simple Mail Transfer Protocol (SMTP) is the de facto standard for e-mail transmission across the Internet. ... The Simple Network Management Protocol (SNMP) forms part of the internet protocol suite as defined by the Internet Engineering Task Force. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... Microsoft TELNET client animation. ... The (new) BitTorrent logo This article is about the protocol. ... The Real-time Transport Protocol (or RTP) defines a standardized packet format for delivering audio and video over the Internet. ... In computing, rlogin is a Unix software utility that allows users to log in on another host via a network, communicating via TCP port 513. ... The Endpoint Handlespace Redundancy Protocol is used by the Reliable Server Pooling (RSerPool) framework for the communication between Pool Registrars to maintain and synchronize a handlespace. ... The Transmission Control Protocol (TCP) is one of the core protocols of the Internet protocol suite. ... The User Datagram Protocol (UDP) is one of the core protocols of the Internet protocol suite. ... The Datagram Congestion Control Protocol (DCCP) is a message-oriented transport layer protocol that is currently under development in the IETF. Applications that might make use of DCCP include those with timingconstraints on the delivery of data such that reliable in-order delivery, when combined with congestion control, is likely... The Stream Control Transmission Protocol (SCTP) is a transport layer protocol defined in 2000 by the IETF Signaling Transport (SIGTRAN) working group. ... Transport layer protocol designed originally as part of the Plan 9 from Bell Labs operating system and used to carry 9P. Its main features are: Reliable datagram service In-sequence delivery Internetworking using IP Low complexity, high performance Adaptive timeouts The original paper describing IL: [1] Categories: Computer stubs ... In computer networking, the Reliable User Datagram Protocol (RUDP) is a transport layer protocol designed at Bell Labs for the Plan 9 operating system. ... The network layer is level three of the seven level OSI model. ... The Internet Protocol (IP) is a data-oriented protocol used for communicating data across a packet-switched internetwork. ... IPv4 is version 4 of the Internet Protocol (IP) and it is the first version of the Internet Protocol to be widely deployed. ... Internet Protocol version 6 (IPv6) is a network layer standard used by electronic devices to exchange data across a packet-switched internetwork. ... The Internet Control Message Protocol (ICMP) is one of the core protocols of the Internet protocol suite. ... The Internet Group Management Protocol is a communications protocol used to manage the membership of Internet Protocol multicast groups. ... In computer networking, the Address Resolution Protocol (ARP) is the method for finding a hosts hardware address when only its protocol address is known. ... Reverse address resolution protocol (RARP) is a protocol used to resolve an IP address from a given hardware address (such as an Ethernet address). ... The data link layer is layer two of the seven-layer OSI model. ... Ethernet is a frame-based computer networking technology for local area networks (LANs). ... Wi-Fi (also WiFi, Wi-fi, Wifi, or wifi) is a brand licensed by the Wi-Fi Alliance to products which pass testing demonstrating that they implement a set of product compatibility standards for wireless local area networks (WLAN) based on the IEEE 802. ... In computing, the Point-to-Point Protocol, or PPP, is commonly used to establish a direct connection between two nodes. ... The Serial Line Internet Protocol (SLIP) is a mostly obsolete encapsulation of the Internet Protocol designed to work over serial ports and modem connections. ... In computer networking, fiber-distributed data interface (FDDI) is a standard for data transmission in a local area network that can extend in range up to 200 km (124 miles). ... Asynchronous Transfer Mode, or ATM for short, is a cell relay network protocol which encodes data traffic into small fixed-sized (53 byte; 48 bytes of data and 5 bytes of header information) cells instead of variable sized packets (sometimes known as frames) as in packet-switched networks (such as... Dynamic synchronous Transfer Mode , or DTM for short, is a network protocol. ... Frame relay, also found written as frame-relay, is an efficient data transmission technique used to send digital information quickly and cheaply to one or many destinations from one or many end-points. ... SMDS, which stands for Switched Multi-megabit Data Services, was a connectionless service used to connect LANs, MANs and WANs to exchange data. ... A local area network (LAN) is a computer network covering a small local area, like a home, office, or small group of buildings such as a home, office, or college. ... International Business Machines Corporation (IBM, or colloquially, Big Blue; NYSE: IBM) is a computer technology firm headquartered in Armonk, NY, USA. The company, which was founded in 1888 and incorporated June 15, 1911, manufactures and sells computer hardware, software, infrastructure services, hosting services, and consulting services. ... MacGyver is one of the symbols of 1980s The 1980s decade refers to the years from 1980 to 1989, inclusive. ... Not to be confused with the Institution of Electrical Engineers (IEE). ... 10BASE-T cable 10BASE-T cable and jackll 10BASE-T is an implementation of Ethernet which allows stations to be attached via twisted pair cable. ... Ethernet is a frame-based computer networking technology for local area networks (LANs). ... The 1990s decade refers to the years from 1990 to 1999, inclusive. ... In computer science, a deterministic algorithm is an algorithm which, in informal terms, behaves predictably. ... In communications, a channel access method is used to share a communications channel or physical communications medium between multiple users. ... Graphics Card IBM XGA-2. ... Madge Networks NV. was a global leader & pioneer of high speed networking solutions in the mid 1990s. ...

Overview

Stations on a Token-Ring LAN are logically organized in a ring topology with data being transmitted sequentially from one ring station to the next with a control token circulating around the ring controlling access. This token passing mechanism is shared by ARCNET, Token Bus, and FDDI, and has theoretical advantages over the stochastic CSMA/CD of Ethernet. ... Token Passing is a technique in which only that system can communicate that has token. ... ARCNET (also CamelCased as ARCnet, an acronym from Attached Resource Computer NETwork) is a local area network (LAN) protocol, similar in purpose to Ethernet or Token Ring. ... Token bus is token ring over a virtual ring on a coaxial cable. ... In computer networking, fiber-distributed data interface (FDDI) is a standard for data transmission in a local area network that can extend in range up to 200 km (124 miles). ... Stochastic, from the Greek stochos or goal, means of, relating to, or characterized by conjecture; conjectural; random. ... In computer networking, Carrier Sense Multiple Access With Collision Detection (CSMA/CD) is a network control protocol in which (a) a carrier sensing scheme is used and (b) a transmitting data station that detects another signal while transmitting a frame, stops transmitting that frame, transmits a jam signal, and then...

Token Ring network

Physically, a Token-Ring network is wired as a star, with 'hubs' and arms out to each station and the loop going out-and-back through each. Cabling is generally IBM "Type-1" Shielded Twisted Pair, with unique hermaphroditic connectors. Image File history File links TokenRingLogicalNetwork. ... Image showing star network layout Star networks are one of the most common computer network topologies. ... A diagram of an STP cable Shielded Twisted Pair, sometimes abbreviated STP, is a kind of copper wiring where a pair of wires are twisted around each other and covered in an insulating tube. ...

Initially (in 1985) Token-Ring ran at 4 Mbit/s, but in 1989 IBM introduced the first 16 Mbit/s Token-Ring products and the 802.5 standard was extended to support this. In 1981, Apollo Computers introduced their proprietary 12 Mbit/s Apollo Token Ring (ATR) and Proteon introduced their 10 Mbit/s ProNet-10 Token Ring network. However, IBM Token-Ring was not compatible with ATR or ProNet-10. This article is about the year. ... A megabit per second (Mbps or Mbit/s or Mb/s) is a unit of data transmission equal to 1,024 kilobits per second or 1048576 bits per second. ... 1989 (MCMLXXXIX) was a common year starting on Sunday of the Gregorian calendar. ... 1981 (MCMLXXXI) was a common year starting on Thursday of the Gregorian calendar. ... Apollo Computer, Inc. ...

More technically, Token-Ring is a local area network protocol which resides at the data link layer (DLL) of the OSI model. It uses a special three-byte frame called a token that travels around the ring. Token ring frames travel completely around the loop. In networking, a communications protocol or network protocol is the specification of a set of rules for a particular type of communication. ... The data link layer is layer two of the seven-layer OSI model. ... The Open Systems Interconnection Reference Model (OSI Model or OSI Reference Model for short) is a layered abstract description for communications and computer network protocol design, developed as part of the Open Systems Interconnection initiative. ...

Each station passes or repeats the special token frame around the ring to its nearest downstream neighbour. This token-passing process is used to arbitrate access to the shared ring media. Stations that have data frames to transmit must first acquire the token before they can transmit them. Token ring LANs normally use differential Manchester encoding of bits on the LAN media. It has been suggested that this article or section be merged with Biphase Mark Code. ...

Token ring was invented by Olof Söderblom in the late 1960s. It was later licensed to IBM, who popularized the use of token ring LANs in the mid 1980s when it released its IBM token ring architecture based on active multi-station access units (MSAUs or MAUs) and the IBM Structured Cabling System. The Institute of Electrical and Electronics Engineers (IEEE) later standardized a token ring LAN system as IEEE 802.5.[1] Olof Söderblom is the creator of Token Ring networking, and grandson of Nathan Soderblom. ... The 1960s decade refers to the years from 1960 to 1969, inclusive. ... MacGyver is one of the symbols of 1980s The 1980s decade refers to the years from 1980 to 1989, inclusive. ...

Token ring LAN speeds of 4 Mbit/s, 16 Mbit/s, 100 Mbit/s and 1 Gbit/s have been standardized by the IEEE 802.5 working group.

Token ring networks had significantly superior performance and reliability compared to early shared-media implementations of Ethernet (IEEE 802.3), and were widely adopted as a higher-performance alternative to shared-media Ethernet. Ethernet is a frame-based computer networking technology for local area networks (LANs). ...

However, with the development of switched Ethernet, token ring architectures lagged badly behind Ethernet in both performance and reliability. The higher sales of Ethernet allowed economies of scale which drove down prices further, and added a compelling price advantage to its other advantages over token ring. A modular network switch with 3 network modules (a total of 24 Ethernet and 14 Fast Ethernet ports) and one power supply. ... ...

Token ring networks have since declined in usage and the standards activity has since come to a standstill as switched Ethernet has dominated the LAN/layer 2 networking market.

Token frame

When no station is transmitting a data 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 transmit data. When a station needs to transmit a data frame, it converts the token frame into a data frame for transmission. The special token frame consists of three bytes as follows:

• 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. Since Manchester encoding is self clocking, and has a transition for every encoded bit 0 or 1, the J and K codings violate this, and will be detected by the hardware.
• Access Control — 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 reserved bits.
• Ending Delimiter — 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.

Encoding of 11011000100 in Manchester code In telecommunication, Manchester code is a form of data communications line code in which each bit of data is signified by at least one transition. ...

Token ring frame format

A data token ring frame is an expanded version of the token frame that is used by stations to transmit medium access control (MAC) management frames or data frames from upper layer protocols and applications. According to the IEEE 802 family of standards Media Access Control (MAC) is the lower sublayer of the OSI data link layer, the interface between a nodes Logical Link Control and the networks physical layer. ...

The token ring frame format is defined as follows:

• Starting Delimiter — as described above.
• Access Control — as described above.
• Frame Control — a one byte field that contains bits describing the data portion of the frame contents.
• Destination address — a six byte field used to specify the destination(s).
• Source address — a six byte field that is either the local assigned address (LAA) or universally assigned address (UAA) of the sending station adapter.
• Data — 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.
• Frame Check Sequence — a four byte field used to store the calculation of a CRC for frame integrity verification by the receiver.
• Ending Delimiter — as described above.
• Frame Status — a one byte field used as a primitive acknowledgement scheme on whether the frame was recognized and copied by its intended receiver.

Active and standby monitors

Every station in a token ring network is either an active monitor (AM) or standby monitor (SM) station. However, there can be only one active monitor on a ring at a time. The active monitor is chosen through an election or monitor contention process.

The monitor contention process is initiated when

• a loss of signal on the ring is detected,
• an active monitor station is not detected by other stations on the ring, or
• when 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.

The station with the highest MAC address 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. In computer networking a Media Access Control address (MAC address) is a unique identifier attached to most forms of networking equipment. ...

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 a 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.

Token ring insertion process

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 insert into the ring and the token ring driver may report an error.

• Phase 0 (Lobe Check) — A station first performs a lobe media check. A station is wrapped 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.
• Phase 1 (Physical Insertion) — A station then sends a 5 volt signal to the MSAU to open the relay.
• 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 copied , 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.
• Phase 3 (Participation in ring poll) — A station learns the address of its Nearest Active Upstream Neighbor (NAUN) and makes its address known to its nearest downstream neighbor, what leads to creating the ring map. Station waits until it receives an AMP or SMP frame with the ARI and FCI bits set to 0. When it does, the station flips both bits (ARI and FCI) 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.
• 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 with which to tell the new station about.

See also

• Cambridge Ring
• Token bus

The Cambridge Ring was an experimental token-passing local area network architecture developed at the Cambridge University Computer Laboratory in the mid-late 1970s and early 1980s. ... Token bus is token ring over a virtual ring on a coaxial cable. ...

External links

• IEEE 802.5 Web Site
• Troubleshooting Cisco Router Token Ring Interfaces
• Data transmission system - United States Patent 4293948