路由表的急剧扩张使得可扩展分布式路由器中线卡的硬件成本迅速增长。提出一种路由表的均衡存储转发模型 RESD (Storage and Decomposition Model based on Even Routing),它属于非完全存储方式。RESD 模型通过初始化分配将长度相邻的前缀尽可能地分配到相同或是相邻的线卡上,然后通过分段式分配均衡每个线卡上的路由数目,最后通过路由特征位信息表和定位路由来实现路由信息的查找。实验证明,该模型可以在路由表分解存储均衡的同时大大减少 LPM匹配中各线卡的并行查找次数。RESD模型的设计和实施原型都是以真实的环境为基础的,因此,RESD 模型与现有网络的体系结构具有良好的兼容性,易于实施。
Sharp expansion of routing table causes the rapid growth in hardware cost of line cards (LCs)in scalable distributed routers. This article proposes a routing table’s equalised storage decomposition and forwarding model (RESD),it is of a non-full backup storage way. The RESD model assigns the neighbouring prefixes with same length to the same or adjacent LCs as much as possible by initialised assignation,and then equalises the routing numbers in each LC by segmented assignation.Finally,the RESD utilises the routing flag bit information table and localisation routing to realise the lookup of routing information.It is proved by the experiment that the RESD model can significantly reduce parallel lookups of each LC in LPM matching while the routing table decomposes the storage for equalisation.Since the design of RESD and its implementation protocol are all based on the real network environment,so RESD model has strong compatibility with current network architecture and is easy to implement as well.