Since there are laminated repeating protection and restoration in an internet laminar model, it makes the realization of the internetwork communication very complex, affects the network transport efficiency and makes the network block. 由于互联网层叠模型中多层都存在重复的保护与恢复机制,致使互联网的实现极其复杂,造成网络传输效率较低,而且拥塞。