An Efficient Content-Addressable Memory Implementation Using Dynamic Routing
An Efficient Content-Addressable Memory Implementation Using Dynamic Routing
复制标题
使用动态路由的高效内容寻址存储器实现
DOI：
10.1109/fccm.2001.12
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Daniel J. Downs
中科院分区：
文献类型：
--
作者：
P. James;Daniel J. Downs
内容可寻址存储器是高速网络设备中的重要组件。本文介绍了一种适用于622 Mb/s通信链路的IPv6流量分类器的宽CAM的设计。设计流程使用标准设计工具与JBits的组合，JBits是一种用于操作可编程资源的低级配置API。CAM为320位宽，以容纳完整的IPv6报头。支持最强大的通配符，范围从不关心头的单个位，一直到不关心整个头。一个优先级机制已被设计，它允许使用显式的优先级编码，而不需要一个昂贵的排序网络。这是通过动态路由来执行的，由此在匹配单元和优先级编码器之间的运行时间确定路由。这允许使用更小、更快的隐式优先级编码器，同时仍然允许显式定义优先级。一个实验设置，它允许128个320位的模式，以50.9 Msearches/s匹配。
Content addressable memories are important components in high-speed networking equipment. This paper describes the design of a wide CAM suitable for use as an IPv6 traffic classifier for a 622Mb/s communications link. The design flow uses a combination of standard design tools in conjunction with JBits, a low-level configuration API for manipulating programmable resources. The CAMs are 320 bits wide to accommodate a full IPv6 header. The most powerful wildcarding possible is supported, ranging from don’t cares on single bits of the header, all the way through to don’t cares for the whole header. A priority mechanism has been designed which allows explicit priority encoding to be used without required a costly sorting network. This is performed by dynamic routing, whereby routes are determined at run-time between the match units and the priority encoder. This allows a smaller, faster implicit priority encoder to be used, whilst still allowing priority to be explicitly defined. An experimental set-up is shown, which allows 128 320-bit patterns to be matched at 50.9 Msearches/s.