摘要： 为了解决移动IP 中的切换时延问题，提出了链路层监测触发和预测链路层切换的两种链路层触发方法。链路层监测触发方法省去了切换中移动检测时间，预测链路层切换方法将网络层切换提前于链路层切换进行。这两种方法通过在链路层属性中绑定网络信息或利用外地代理获得当前子网与相邻子网的网络信息的方法，判断发生了网间切换时才进行触发，避免了由链路层触发而导致的网络层的盲目切换。

关键词: 移动IP；切换；链路层触发

Abstract: To reduce handoff latency in mobile IP, two link layer trigger methods are proposed. The link layer inspection method removes thelatency of movement detection and the method of link layer handoff prediction can trigger network layer handoff before link layer handoff. Thesemethods trigger network handoff only when it is decided the mobile node enters into new subnet through binding network information in link layerproperty of base station or acquiring information of current subnet and neighboring subnet from foreign agent, so these methods can avoid blindnetwork handoff.

Key words: Mobile IP; Handoff; Link layer trigger