This work proposes Practical Byzantine Fault Tolerance (PBFT) ordering service needed for block formation in permissioned blockchain environments. Contrary to current PBFT implementations that only provide a single point of entry to the ordering service, we allow each ordering node to act as an entry point that proposes and conducts the consensus process of including new record in the distributed ledger. To ensure atomicity of record insertion in distributed ledger, we have developed a bandwidth reservation protocol that uses a modification of CSMA/CA protocol to regulate access to the broadcast medium formed by the P2P network of TCP connections between orderers. We have modeled record insertion service time in a cluster where ordering nodes have random position within Cartesian coordinate system. We have also modeled total request access time to the ledger which includes waiting time in the orderer's queue and record insertion time. These models are used to evaluate system performance under variable request rate ordering service, variable number of nodes and variable physical cluster dimensions. Our results show the interaction between decreased request waiting time in orderer's queue and increased contention among orderers when the number of orderers increases for the given total request arrival rate. This interaction is also investigated for two different physical cluster sizes which affect record insertion time. The interplay of request rate, number of orderers and physical cluster size determines system capacity expressed in total request rate. Our model can be used to make the trade-off between the required system capacity, number of orderers, and physical cluster dimensions under constraints on Byzantine fault rate.

中文翻译：

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调整PBFT以与启用区块链的IoT系统一起使用

这项工作提出了在许可的区块链环境中形成块所需的实用拜占庭容错（PBFT）订购服务。与目前仅提供订购服务的单个入口点的PBFT实现相反，我们允许每个订购节点充当入口点，该入口点提议并执行将新记录包括在分布式分类帐中的共识过程。为了确保记录在分布式账本中的原子性，我们开发了一种带宽预留协议，该协议使用对CSMA / CA协议的修改来调节对订购者之间TCP连接的P2P网络形成的广播媒体的访问。我们对集群中的记录插入服务时间进行了建模，其中排序节点在笛卡尔坐标系中具有随机位置。我们还对总账的总请求访问时间进行了建模，其中包括订购者队列中的等待时间和记录插入时间。这些模型用于评估可变请求速率订购服务，可变节点数和可变物理群集尺寸下的系统性能。我们的结果表明，在给定的总请求到达率下，订购者数量增加时，订购者队列中请求等待时间的减少与订购者之间争用的增加之间的相互作用。还针对影响记录插入时间的两个不同物理簇大小研究了这种交互。请求速率，订购者数量和物理群集大小之间的相互作用决定了以总请求速率表示的系统容量。我们的模型可用于在所需系统容量之间进行权衡，