Implementation Of PIM-SM On ACR And Its Key Technology Research

As the most popular intra-domain multicast routing protocol presently, PIM-SM has strong ability of transferring data. It is the main multicast protocol which Large-scale Access Convergence Router(ACR) must realizes and its forwarding performance will exert direct influence on that whether ACR can sustain high quality multicast applications commendably.Popular PIM-SM protocol implementation scheme is often difficult to accord with the architecture characteristics of ACR and to arrive at the forwarding performance which increasing data flux of Internet needs and the real-time characteristic of multicast applications. This paper proposes a distributing implementation scheme of PIM-SM to satisfy the requirements of ACR for the sake of improving forwarding performance, and presents the improving scheme for the problems of the ptotocol PIM-SM discovered in the test.The key idea of the distributing implementation scheme of PIM-SM is that the control plane and data plane of PIM-SM are separately implemented. In order to forward data as fast as possible, the data plane of protocol is realized in TCAM+FPGA manner, the control plane is realized by software and they are connected through high-speed inner network. This paper analyzes the problem of plane coherence due to distributing implementation scheme of PIM-SM and proposes a way to solve it through message mechanism on ACR flat.This paper analyzes the influences to the router by delivering register message to control plane and the frequentely reporting of KAT(Keep Alive Timer) message, and presents a scheme with the sending of resgister message realized on hardware and a rate limitation algorithm of KAT reporting. Through the specific analysis of protocol forwarding rules, this paper designs the format of forwarding table and the forwarding process of multicast data on hardware. After the implementation of PIM-SM on ACR, we have done some test in protocol coherence and forwarding performance, the test proved that the scheme can guarantee the integrity of protocol and achieve the goal of 10G line speed forwarding.In the test, there would be packets lost when unicast routing changes or bootstrap router come down. To solve these problems, this paper presents an improving scheme in protocol, simulation and performance analysis proves that the packets lost is large reduced.