Notes when using the Loop detection and blocking function - Disable the functionon the upstream switch192If you configure a network only with switches having the Loop detection andblocking function, the upstream switch may detect a loop occurring on the down-stream switch first depending on the condition. Then, all communications to thedownstream switch may be blocked.To minimize the impact of communication blocks caused by loop detection, theLoop detection and blocking function needs to be disabled on the upstreamswitch. Then, network configuration and switch settings need to be changed toblock only the port having a loop on the switch.Upstream switchDownstreamswitch 1Downstreamswitch 2PC 1 PC 2 PC 3(1)(4)(3)(2)[Occurrence conditions](1) Communication is taking place between PC 1 and PC 2, andbetween PC 1 and PC 3.(2) A loop occurs on downstream switch 2.(3) The upstream switch detects the loop first and blocks the uplinkport on downstream switch 2. (Normally, only the loop-con-nected port is blocked.)(4) The uplink port on downstream switch 2 is linked down, and allcommunication to other switches is blocked.Figure 5-2 Notes when using the Loop detection and blocking function
