令牌环网络最初是由IBM在20世纪70年代开发的。它现在仍然是IBM的主要局域网络（LAN）技术。相关的IEEE 802.5规范与IBM的令牌环网络几乎是相同的,完全兼容。事实上,IEEE802.5规范仿照IBM令牌环，并不断跟踪IBM的令牌环网开发。术语令牌环网一般通常用来既指IBM的令牌环网,也指IEEE 802.5网络。本文讨论令牌环网和IEEE802.5这两者。-The Token Ring network was originally developed by IBM in the 1970s. It is still IBM s primary local-area network (LAN) technology. The related IEEE 802.5 specification is almost identical to and completely compatible with IBM s Token Ring network. In fact, the IEEE 802.5 specification was modeled after IBM Token Ring, and it continues to shadow IBM s Token Ring development. The term Token Ring generally is used to refer to both IBM s Token Ring network and IEEE 802.5 networks. This article addresses both Token Ring and IEEE 802.5.