However, the frames are not forwarded by normal bridging procedures. 但是,这些讯框不会被正常的桥接程序所转送。
To alleviate this, bridging was created to communicate at the data link layer while isolating the physical layer. 为了减轻这个问题,桥接方法被采用,在工工作在物理层的中继器之基础上,桥接工作在数据链路层。