1、当交换机从一个端口收到无差错的帧,且向目的地址转发此帧时也要通过此端口,则交换机自动丢弃此帧。(详细叙述:从端口x收到无差错的帧,如有差错即丢弃,在转发表中查找目的站MAC地址。如到这个MAC地址去的端口d=x,则丢弃此帧,因为这表示不需要经过网桥进行转发。否则从端口d转发此帧。)2、网桥按照以下算法处理收到的帧和建立转发表 1, when the switch receives an error-free frame from a port and forwards the frame to the destination address, the switch also discards the frame automatically. (Described in detail: Receive error-free frames from port x, discard them if there is any error, look up the MAC address of the destination station in the forwarding table, discard this frame if the port d = x to this MAC address, because this means Do not need to be forwarded through the bridge, or from the port d forwarding this frame.) 2, the bridge in accordance with the following algorithm to process the received frame and the establishment of forwarding table