Figure 4a-1: Ring Network Wrapped Ring Access Unit Main ring Backup Ring Token Break=n了 StP or UTP 1. Frames travel around the ring The ring is a dual ring 2. If a trunk line between Normally, the backup ring is not used access units breaks The ring is wrapped Computer Computer A Computer C so the loop is restored 22 Figure 4a-1: Ring Network STP STP or UTP Main Ring Backup Ring Break Wrapped Ring Access Unit Token Computer A Computer B Computer C Computer E Computer D 1. Frames travel around the ring. The ring is a dual ring. Normally, the backup ring is not used. 2. If a trunk line between access units breaks, The ring is wrapped, so the loop is restored