Clock-RSM: Low-Latency Inter-datacenter State Machine Replication Using Loosely Synchronized Physical Clocks

Du, Jiaqing; Sciascia, Daniele; Elnikety, Sameh; Zwaenepoel, Willy; Pedone, Fernando

doi:10.1109/dsn.2014.42

Cited by 27 publications

(24 citation statements)

References 13 publications

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“…In worst case, every request may necessitate a consensus run per state change, thus preventing fast network reconfigurations and introducing a bottleneck on control plane, and ultimately data-plane. Although slight variations of Paxos, including the recent RAFT [10] consensus algorithm, were proposed in literature [10]- [12], the general concept and signaling overhead of the algorithm is unchanged.…”

Section: Accept-responsementioning

confidence: 99%

Towards adaptive state consistency in distributed SDN control plane

Sakic

Sardis

Guck

et al. 2017

2017 IEEE International Conference on Communications (ICC)

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State synchronisation in clustered Software Defined Networking controller deployments ensures that all instances of the controller have the same state information in order to provide redundancy. Current implementations of controllers use a strong consistency model, where configuration changes must be synchronised across a number of instances before they are applied on the network infrastructure. For large deployments, this blocking process increases the delay of state synchronisation across cluster members and consequently has a detrimental effect on network operations that require rapid response, such as fast failover and Quality of Service applications. In this paper, we introduce an adaptive consistency model for SDN Controllers that employs concepts of eventual consistency models along with a novel 'cost-based' approach where strict synchronisation is employed for critical operations that affect a large portion of the network resources while less critical changes are periodically propagated across cluster nodes. We use simulation to evaluate our model and demonstrate the potential gains in performance.

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Section: Accept-responsementioning

confidence: 99%

Towards adaptive state consistency in distributed SDN control plane

Sakic

Sardis

Guck

et al. 2017

2017 IEEE International Conference on Communications (ICC)

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“…Some state-machine replication protocols do use physical clock timestamps, but only to improve performance[19].…”

mentioning

confidence: 99%

The Quest for Scalable Blockchain Fabric: Proof-of-Work vs. BFT Replication

Vukolić¹

2016

Lecture Notes in Computer Science

722

507

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Bitcoin cryptocurrency demonstrated the utility of global consensus across thousands of nodes, changing the world of digital transactions forever. In the early days of Bitcoin, the performance of its probabilistic proof-of-work (PoW) based consensus fabric, also known as blockchain, was not a major issue. Bitcoin became a success story, despite its consensus latencies on the order of an hour and the theoretical peak throughput of only up to 7 transactions per second. The situation today is radically different and the poor performance scalability of early PoW blockchains no longer makes sense. Specifically, the trend of modern cryptocurrency platforms, such as Ethereum, is to support execution of arbitrary distributed applications on blockchain fabric, needing much better performance. This approach, however, makes cryptocurrency platforms step away from their original purpose and enter the domain of database-replication protocols, notably, the classical state-machine replication, and in particular its Byzantine fault-tolerant (BFT) variants. In this paper, we contrast PoW-based blockchains to those based on BFT state machine replication, focusing on their scalability limits. We also discuss recent proposals to overcoming these scalability limits and outline key outstanding open problems in the quest for the "ultimate" blockchain fabric(s).

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“…Strongly consistent transactional systems. Many systems support geo-replication with consistency guarantees stronger than CC (e.g., Spanner [1], Walter [43], Gemini [44], Lynx [45], Jessy [46], Clock-SRM [47], SDUR [48] and Droopy [49]). These systems require cross-DC coordination to commit transactions, hence they are not always-available [11], [19].…”

Section: Related Workmentioning

confidence: 99%

Wren: Nonblocking Reads in a Partitioned Transactional Causally Consistent Data Store

Spirovska

Didona

Zwaenepoel

2018

2018 48th Annual IEEE/IFIP International Conference on Dependable Systems and Networks (DSN)

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Transactional Causal Consistency (TCC) extends causal consistency, the strongest consistency model compatible with availability, with interactive read-write transactions, and is therefore particularly appealing for geo-replicated platforms. This paper presents Wren, the first TCC system that at the same time i) implements nonblocking read operations, thereby achieving low latency, and ii) allows an application to efficiently scale out within a replication site by sharding. Wren introduces new protocols for transaction execution, dependency tracking and stabilization. The transaction protocol supports nonblocking reads by providing a transaction with a snapshot that is the union of a fresh causal snapshot S installed by every partition in the local data center and a client-side cache for writes that are not yet included in S. The dependency tracking and stabilization protocols require only two scalar timestamps, resulting in efficient resource utilization and providing scalability in terms of replication sites. In return for these benefits, Wren slightly increases the visibility latency of updates. We evaluate Wren on an AWS deployment using up to 5 replication sites and 16 partitions per site. We show that Wren delivers up to 1.4x higher throughput and up to 3.6x lower latency when compared to the state-of-the-art design. The choice of an older snapshot increases local update visibility latency by a few milliseconds. The use of only two timestamps to track causality increases remote update visibility latency by less than 15%.

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Clock-RSM: Low-Latency Inter-datacenter State Machine Replication Using Loosely Synchronized Physical Clocks

Cited by 27 publications

References 13 publications

Towards adaptive state consistency in distributed SDN control plane

Towards adaptive state consistency in distributed SDN control plane

The Quest for Scalable Blockchain Fabric: Proof-of-Work vs. BFT Replication

Wren: Nonblocking Reads in a Partitioned Transactional Causally Consistent Data Store

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