End-to-end delay has three components. Delay can be introduced in the network as serialization delay, propagation delay, or NE processing delay. Serialization delay has the most significant impact on end-to-end delay. 端到端的时延包含三各部分,它们是串行时延,传播时延,网元处理时延。串行时延对端到端时延的影响最大。