MANET与Internet互联时的自适应增强机制

移动自组网(MANET)与Internet的互联能有效扩展Internet覆盖和MANET应用范围。针对既有互联协议无法适应MANET动态变化的网络条件,在网关发现过程中形成广播风暴以及将全局路由建立于单向链路上等原因所导致的互联性能恶化,提出了一种具有自适应增强机制的互联协议,该协议一方面依据实际网络条件与Internet访问需求自动调整网关通告分组在MANET中的覆盖范围;另一方面,基于网络条件自适应调整发送间隔的HELLO分组可同时避免全局路由计算过程引入单向链路以及形成广播风暴。仿真结果表明,此自适应增强协议能够以合理的开销,在复杂而多变的应用环境下为MANET提供优化的互联性能。

Adaptive Mechanisms to Enhance Internet Connectivity for Mobile Ad Hoc Networks

In this paper,an internetworking algorithm with adaptive mechanisms has been proposed to enhance Internet connectivity for mobile Ad Hoc networks.Firstly,through exchanging hello packets which are identical to the AODV hello packets except for the additional symmetric neighbor list and asymmetric neighbor list fields,unidirectional links are removed from route computations and redundant or even harmful rebroadcasting of the broadcast packets are inhibited simultaneously in the procedure of gateway discovery.Secondly,based on the dynamic adjustment of the scope of the gateway advertisement packets and the intervals of sending hello packets according to the network conditions change,a lot of unnecessary overhead is reduced.Performance results using ns-2 simulations,under varying number of unidirectional links and node speeds,show that this adaptive Internet connectivity scheme can provide better performance than others due to its adaptive mechanisms,avoiding unidirectional links as well as relieving broadcast storm,and is a step closer to making the large-scale deployment of mobile Ad Hoc networks a reality.