Amendment Standard - Superseded. This IEEE Standards product is part of the 802 family on LAN/MAN. Extensions to the IEEE 802.5 Token-Passing Ring standard are defined. These extensions implement a Dual Ring local area network (LAN) topology that provides full interoperability between stations conforming to IEEE Std 802.5, including coexistence on the same ring, and recovery from all single media failures with full capability restored. The Dual Ring Topology and operation described are intended for applications that require very high availability and recovery from media and station failures.