PMST:一种面向高性能IP查找的双向平衡流水线结构

Abstract

With the rapid development of network technology and the growing diversity of network applications, IP lookup, as a core function of routers, has been confronted with serious challenges, ranging from throughput, memory efficiency and update performance. Benefiting from the pipeline technology, the throughput of IP lookup has been improved significantly. However, unbalanced structure will not only lead to low memory efficiency and high update overhead, but also influence the lookup performance and the load balance of multi-pipeline architectures. While existing solutions to balance optimizing would bring some indispensable new problems, impending their applications in IPv6 or large-scale routing tables. In view of this, this paper proposes a balanced bidirectional pipeline architecture—pipelined multi-bit split tree (PMST). After splitting prefixes, reversing a sub-tree and a series of optimizations, PMST can achieve a desirable balance degree at the cost of only a few stages. What is more, PMST also realizes significant improvements on comprehensive performance. Large IPv6 routing data sets generated in some manner, as well as real-world IPv4/v6 routing data sets, are used to evaluate the performance of PMST comprehensively. According to the experimental results, when achieving a desirable balance degree, the number of stages cost in PMST decreases by 75%~85.7% in comparison to existing solutions. Meanwhile, the superiorities of PMST on pipeline latency, average memory accesses per lookup, on-chip memory efficiency, update overhead and the load balance of multi-pipeline architecture are also significant. Therefore, PMST has higher comprehensive performance and better scalability, which can better meet current and future demands.