Design And Implementation Of High-speed Forwarding Engine Based On Terabit Router

With the ongoing explosive growth of the Internet, there is urgent need of more research and study about terabit (1012bit) core router. One of the key technologies in high performance terabit router, high speed forwarding engine is studied in detail in this paper. This thesis studies the theory and implementation of high speed forwarding engine under the 863 High-technology Program "The fundamental platform and experimental system of the high performance IPv4/v6 terabit scalable router". The main contributions of this paper can be concluded as follows:The present status and future trend of terabit high performance routers are analyzed, and the high speed forwarding engine related technologies are summarized. Then we introduce the key technology of high performance router. All the conclusions in this paper have universal guidance for further research.We analyze the design requirements of high performance forwarding engine and introduce one of the important technology-lookup tables with line speed. The forwarding performance standard is studied from four aspects, the lookup tables speed, the table update speed, the routing table capacity and memory space. Then we introduce the routing lookup algorithms based on CAM/TCAM. We use hardware lookup tables instead of software lookup. These works will be valuable for the following terabit router OC-768 (40Gbps) interfaces' forwarding design.We summarize the function of terabit forwarding engine, and then analyze its implementation, based on the high performance demand of terabit forwarding engine, a structure called Parallel Pipeline High speed Forwarding Engine Based on FPGA is presented, Analysis and experiment proved that the performance of the forwarding engine can reach our design aim effectively and satisfy the whole demands of terabit router, and support Multicast and QoS service. Experiment and analysis proved that the performance of the forwarding engine can reach 31.25Mpps forwarding rate. They satisfy IPv6 and IPv4/IPv6 dual-stack core routers' OC-192 (lOGbps) interfaces' line speed forwarding.We analyze the unicasU multicast and security lookup tables technology in detail. Then we summarize the multicast forwarding process for PIM protocol and analyze the implementation of multicast forwarding table lookup. A scheme called Parallel TCAM and Pipeline Multicast Forwarding Scheme Based on the Method of Double Entry Placed Together is presented.