Token Ring

Abstract

So far we have discussed just Ethernet technologies. Another very important technology that has shaped LANs for decades is the Token Ring. It is a LAN concept whose physical, MAC, and logical link layered protocol structures are defined in the IEEE 802.5 standard. A subset of this standard also defines High-speed Token Ring (HSTR) protocol structures. Token Ring technology uses ring topology for data transfers and provides more advanced congestion management than that available in Ethernet. One of the major advantages of the Token Ring (TR) is no collision in the network and, therefore, utilization can reach 100% under heavy load. TR is very complex to install and maintain, and a deep understanding of the technology is required. Conversely, Ethernet is simple and very easy to install. Despite its many disadvantages, Ethernet has taken the market by storm because of its simplicity. TR on the other hand was not widely accepted in the LAN. It was considered as IBM technology and thought to coexist only with IBM’s synchronous network architecture. However, as of today, a number of companies have started manufacturing TR products and the technology itself has received some attention in the LAN market. To cope with market demands, TR protocol structures have improved efficiency in bandwidth on demand, QoS, and traffic prioritization. In fact, the TR protocol is more improved and can provide more effective traffic management than any other LAN technology currently available.