基于隐式Flow Splitter的负载均衡交换结构

摘要

为解决Byte-Focal结构存在的计算复杂度较高及“伪队头阻塞”等问题,提出一种基于隐式Flow Splitter的负载均衡交换结构(load balanced switch based on implicit flow splitter,LB-IFS).LB-IFS在输入端引入双缓冲模式和两步调度策略,较好地解决了“伪队头阻塞”问题且能使信元以不失序的状态离开第1级crossbar,同时输入端设置隐式Flow Splitter为每个信元分配一个理论转发路径；输出端利用VIQ(virtual input queuing)结构的重排序缓存,结合理论转发路径,方便地实现信元的有序转发.理论分析和仿真都表明:LB-IFS能保证全流程计算复杂度均为O(1)且其时延性能优于Byte-Focal.%In order to solve the problems of high computation complexity, PHOL (pseudo head of line) blocking, etc. in Byte-Focal switches, this paper proposes a load balanced switch architecture called LB-IFS (load balanced switch based on implicit Flow Splitter). LB-IFS promotes a DBM (double-buffering mode) and a 2-step scheduling scheme to satisfactorily solve the PHOL problem and ensure that packets of the same flow depart from the first crossbar in the same order as they arrive. Furthermore, the novel IFSs (implicit flow splitters) at the input port assign a TFP (theoretical forwarding paths) for individual cells to be used by output ports. The RB (re-sequencing buffer) organized in VIQ (virtual input queue) structure, in conjunction with TFPs, will ensure that packets can be emitted out of switch without disordering conveniently. Theoretic analysis and simulation results have shown that LB-IFS has better performance than Byte-Focal in delay and ensures the computation complexity of O(1) in the whole switching process.