计算机工程 ›› 2010, Vol. 36 ›› Issue (8): 117-119.doi: 10.3969/j.issn.1000-3428.2010.08.041

• 网络与通信 • 上一篇    下一篇

基于TCAM报文分类的范围编码方案

梁仲斌1,兰巨龙1,夏 斌2   

  1. (1. 国家数字交换系统工程技术研究中心,郑州 450002;2. 中国石油集团海洋工程有限公司,北京 100176)
  • 收稿日期:1900-01-01 修回日期:1900-01-01 出版日期:2010-04-20 发布日期:2010-04-20

Range Encoding Scheme Based on TCAM Packet Classification

LIANG Zhong-bin1, LAN Ju-long1, XIA Bin2   

  1. (1. National Digital Switch System Engineering & Technological R&D Center, Zhengzhou 450002;2. China National Petroleum Offshore Engineering Co., Ltd., Beijing 100176)
  • Received:1900-01-01 Revised:1900-01-01 Online:2010-04-20 Published:2010-04-20

摘要: 针对现有范围编码方案三态内容寻址存储器(TCAM)利用率不高及更新性能差问题,提出一种混合范围编码方案(Hybrid-RES),根据扩展系数和出现频率,采用纵向或横向扩展编码策略对范围字段进行编码。纵向扩展编码策略利用格雷码的对称映射特征设计一种格雷范围编码算法,对纵向扩展出TCAM表项数目较多的范围字段采用横向扩展编码策略。理论分析和实验结果表明,Hybrid-RES可以较大地提高TCAM利用率,同时获得较好的更新性能。

关键词: 三态内容寻址存储器, 范围匹配, 格雷码, 比特向量映射

Abstract: Aiming at the problem of Ternary Content Addressable Memory(TCAM) storage efficiency low and updating performance, a Hybrid Range Encoding Scheme(Hybrid-RES) is proposed, which encodes range rules by either horizontal or vertical expansion based on the rule’s expansion ratio and frequency. It designs a Gray-based range encoding algorithm to expand range rules in vertical direction, and extra bits are used in bit vector mapping range encoding for rules that need many TCAM entries to represent. Performance analysis and experimental result show that the Hybrid-RES can significantly improve TCAM utilization and obtain better average updating complexity.

Key words: Ternary Content Addressable Memory(TCAM), range matching, Gray code, bit vector mapping

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