Token Ring and FDDI technologies have significantly more complex implementation than the same Ethernet technology on a shared data environment. Much of this complexity was due to the fact that the developers have tried to improve the effectiveness of the technology: to increase fault tolerance, make the environment predictable design priority service specific data packets, such as voice traffic, which is sensitive to delays. In this they succeeded, for example, a more advanced version of Token Ring, FDDI namely for a long time been used as a campus backbone networks of enterprises.
Data transfer rate in Token Ring networks
Initially, the data rate is 4 Mbit / s when it was first developed by the company in the IBM, but was later increased to 16 Mbit / s. Addressing in local networks was the same as in Ethernet technology, that is MAC-addresses are the same size.
Network access method
In Token Ring networks to determine the sequence of nodes that have access to the transmission medium used by Special frame - a token, or a token. Token Ring technology has a ring topology and the token is passed from node to node in one direction. The node that owns the token, has the right to broadcast information in a shared data environment. Thus there is no question of conflicts in the shared data environment, which are present in the Ethernet technology. There is also a time limit on the ownership of the token to the node could not monopolistically fully capture all network resources. When the time of possession node transmits the token neighbor node.
Transfer token in the Token Ring network between nodes The problem of transmission of delay-sensitive traffic is solved by prioritizing training. The transmitting node sets the priority of each frame. Also, the token itself is always a certain level of priority at any given time.
FDDI technology
Technologists FDDI is an advanced version of Token Ring technology. It also uses a ring topology and the transfer of the token from node to node. A difference is that FDDI operates at high speed and has a better mechanism to ensure fault tolerance. Also this is the first technology that started using an optical fiber. Optical fiber is used as the start time with the 70-ies of the last century.
Transfer token in FDDI This technology has two rings for transmission of data. The primary ring is the main and it all traffic is transmitted and the secondary reserve. In case of failure of one of the nodes. Nearby sites wrapped traffic to a second ring and a ring topology for reduced backup path. Formed flat ring topology.
