The Research And Implementation Of Multi-protocol Supporting Policy Of 10Gbps Forwarding Engine

People bring forward more requirements on routers with the rapid bandwidth growth of the optical transmission network and the development of service diversity of IP network. On one hand, routers must sustain the link rate which grows faster and faster, and on the other hand, they have to support IPv4,IPv6 and MPLS protocols. Forwarding engine is the key to realize high speed operation of various protocols in router, which plays a core role in router processing. Aiming at the 10Gbps multiprotocol forwarding engine of the terbit router and according to the requirements on one of key projects of the National 863 Program for the Tenth Five-year Plan "The basic platform and experiment system for terabit scalable high performance IPv4/v6 routers", this dissertation is devoted to the research of 10Gbps forwarding engine supporting IPv4/v6/MPLS protocols and their implementation. The mail work of this dissertation is as follows:Based on an indepth study of forwarding process, introducing parallel process and pipeline technology, a parallel pipeline forwarding engine structure based on FPGA is proposed. Theoretical analysis of some key parameters of the pipeline is given, throughput included.The unicast, multicast and MPLS packets forwarding process are summarized. Pointing out the disadvantages of the forwarding engine structure based on multiple channels process, a forwarding engine pipeline structure based on IPv4/v6/MPLS single channel process is proposed. This structure saves FPGA both logical and storage resources and uses a more simple logical control.The performance of forwarding engine based on proposed structure is analyzed and the result of its forwarding abilities under different link interfaces is drawed, which could also provide theoretical clues for project test.A new parallel lookup scheme for multicast and security inspect table is proposed, analyzing the currently popular TCAM pipeline lookup sheme. And a unicast table lookup scheme based on IPv4 soft configuration is also proposed. This mechanism is proved to meet requirements of lookup at line-speed and save TCAM resources.The engineering implementation result of the 10Gbps multiprotocol forwarding engine in terabit router is given, which proves that the forwarding engine with schemes proposed above can support 10Gbps POS and 10Gbps LAN/WAN interfaces forwarding at line-speed.