Although the CPU of the network equipments become more quickly and the bandwidth of networks continue increasing, the networks can not satisfy the more increase of application requirement.

• 网络应用的巨大需求导致网络系统经常会出现拥塞现象，虽然网络设备的处理速度不断加快、网络带宽持续增长，但是硬件的建设的速度有时赶不上应用需求的增长。