A Special Purpose Content Addressable Memory for Network Packet Classifier

• Main Authors: Long-En Lee, 李龍恩
• Other Authors: Shih-Hsu Huang
• Format: Others
• Language: zh-TW
• Published: 2003
• Online Access: http://ndltd.ncl.edu.tw/handle/xad5w7

碩士 === 中原大學 === 電子工程研究所 === 91 === The internet is formed by reticulated connections that are mutually connected and these network points are composed by a router. In virtue of the Internet information data is increasing rapidly makes the existent bandwidth not useful enough. Therefore brings the concept of different service. Different service needs that routers in each network point look up the internet protocol in the packet header and give a suitable action at the right time. Then the data can be sent to the destination without any problem according the administrator. When the data is being classified needs to look up the information in the header and find out if they can fit in with the rules defined previously. Once the quantity of rules increases, the look up time increases proportionally. The special hardware architecture design of a Content addressable memory can finish the look up in a specific time which makes it suitable to look up in a high speed packet classification. But the use of it is limited because the Content addressable memory needs more cost and power consumption. The data search is compared by bit, therefore could produce a (2W-2) expand factor as the worst situation. One rule probably needs a number of Content addressable memory entries which makes it no efficient. This paper proposed a special purpose content addressable memory to avoid the multiplicative factor where one rule only needs an entry. The coming of IPV6 can use the special purpose content addressable memory to compose the frame that the packet classification needs for data search. Finally we use the TSMC 0.35um and the fully-custom methodology to implement the special purpose content addressable memory. Then we use transistor level simulation tool called “TimeMill” to verificate the functions and the timing.