It was made by IBM in 1970. The token ring is maintained in accordance with the IEEE 802.5 standard. It remains the primary network for IBM's LAN technology so far.Has happened . It is a LAN in which all the computers are connected in a ring or star topology. Token Ring is more complex than Ethernet, because all stations are connected to a single device, called a Multistation Access Unit (MSAU). In fact, IEEE 802.5 does not specifically mention any topology, but virtually operates on the IEEE 802.5 star topology.
It consists of a token that spins in a ring, which rotates in a round-robin manor. In this protocol a special bit pattern is rotated in the ring. This bit pattern is called a token. In this, the token moves from one computer to another, in which the token comes from Nearest Active Upstream Neighbor (NAUN). When the computer receives a token, then it checks the address of that token, if that address matches the address of that computer, then that data is given to that computer, otherwise the token is sent to the Nearest Active Downstream Neighbor (NADN). is given.
In this, all the stations are connected to the MSAU like a star, and it acts like a logical ring. There is a token in the ring, which keeps rotating in the ring. The token always rotates in the same direction. The station to which the packet is to be sent, grabs the token from the ring and sends it to the NAUN. This token passes through each station and that station frees that token, otherwise that token goes to NADN. This process runs in a round-robin process. This process is operated through two modes Listen and Transmit Ring. Ethernet is not a broadcast medium like a token bus, but rather connects several stations point-to-point in sequence. The interface used in ring network is called active interface. Ring networks can run on twisted pair coaxial cable or fiber-optical cable.
Token Ring solves the Collision problem like Ethernet, in that the token is sent to the station that wants to send the data, which increases the efficiency of the system and also provides priority scheme and acknowledgment.
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| Token and data/command frame |
(i) Start Delimiter - It specifies the start of the frame. It uses different Manchester encoding of non data symbols.
(ii) Access Control - It holds the token bit, monitor bit, priority bit, and reservation bit which tells which bit is being used.
(iii) Frame Control - It distributes data frames from different control frames.
(iv) Destination Address - In this the address of the station to which the frame will be sent is kept. This unit can be a physical address, a group of addresses, or a global address.
(v) Source Address - In this, the address of the station to which the frame is being sent is kept.
(vi) Data Field - This is a required field, which indicates that the frame will be transmitted in the token holding type. There is no limit to this frame.
(vii) Frame Check Sequence (FCS) - This is a 32-bit cyclic redundancy check that detects errors.
(viii) End Delimiter (End Delimiter) - It indicates the end of the frame -
(ix) Frame Status - It is not used in any other protocol. It is used to indicate the status of data at any station in the ring. is done
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