拜占庭环境下新成员加入容错组状态同步

State synchronization for new member join in Byzantine-tolerant environments

在主动复制技术下,为了容忍少量节点的拜占庭错误并提高组成员加入时状态同步的效率,提出了快速状态同步协议FSSP.FSSP利用Erasure Coding将状态数据分成P块,经过线性运算,编码成Q块(Q>P).新加入节点只需获得Q块中的任意P块数据即可完成解码,获得状态数据.同时FSSP使用Hash技术屏蔽了拜占庭节点带来干扰.仿真实验结果表明:在100M bit/s以太网环境下,网络传输时延是系统的主要瓶颈,无论待同步状态数据驻留在内存还是硬盘中,FSSP均要优于直接同步协议DSSP.这是因为FSSP有效地减少了网络中传输的报文量,以少量的编解码计算代价换取了较大的网络传输时延,最终达到了加快状态同步过程的目的.

With active replication technique, in order to tolerate Byzantine failure that a few nodes may suffer from and improve the performance of state synchronization when new member joins in, a novel fast state synchronization protocol （FSSP） is proposed. By utilization of Erasure Coding, FSSP divides the state data into P blocks which are then encoded into Q blocks （ Q 〉 P） through lin- ear operation. The new member only needs to get P blocks among Q to decode the original state data. Meanwhile, FSSP can mask some Byzantine failure by using Hash technique. The simulation results show that with 100 Mbit/s Ethernet, the delay of network transmission is the bottleneck. FSSP is better than directly synchronization protocol （DSSP） no matter whether the state data is in memory or in disk. Although FSSP brings a little cost of coding and decoding, it reduces a lot of data transferring in networks and finally it achieves the purpose of improving the performance of state synchronization.