应用双层指针缩短切换时延及优化路由的分布式移动性管理方案

根据锚点位置固定有否,移动IP协议分为锚点固定的移动性管理协议和分布式移动性管理协议两类,后者允许移动节点在会话开始时动态地选择较近的接入路由器作为锚点,从而可以缩短切换时延并实现近似最优的路由.然而,对于给定的会话,锚点的位置是固定的,在会话持续时间内进行移动节点切换时,切换操作与锚点固定的移动性管理协议相同,存在切换时延长和路由欠优问题.为解决该问题,提出了应用双层指针的分布式移动性管理方案.使用"低层指针"在具有移动性管理功能的接入路由器间建立指向关系以缩短切换时延;使用"高层指针"定期向锚点或对端节点注册优化路由并动态更换锚点;推导了所提方案和已有方案的切换时延公式.数值分析和仿真结果表明,所提方案可以缩短分布式移动性管理的切换时延.

Handoff delay reducing and routing optimizing scheme by two-level pointers for distributed mobility management

According to the location of the anchor, the mobility IP (MIP) protocols can be divided into the fixed anchor mobility management protocols and the distributed mobility management (DMM). The DMM can reduce handoff delay and acquire near-optimal routing by letting mobile node (MN) choose a nearby access router as its anchor. However, the anchor is chosen at the beginning of a session and fixed during the MN's movement, which may lead to large handoff delay and sub-optimal routing problems when a MN undergoes many handoffs in a given session. In this case, the handoff process is the same with that of the fixed anchor mobility management protocols. To address this problem, a scheme using two-level pointers is proposed. The lower pointer reduces handoff delay by constructing a pointer chain between mobility capable access router (MAR), and the higher pointer optimize routing by updating MN's location to local mobility anchor (LMA) or correspondent node (CN). Thus, the anchor can be changed dynamically. Furthermore, the handoff delay under our scheme and the existing schemes are derived. Numerical analysis and simulation indicate that our scheme can reduce handoff delay of DMM.