Blockchain technologies are based on concepts such as asymmetric encryption, hash algorithms, distributed structure, smart contracts, and consensus mechanisms. Consensus mechanisms are methods that ensure that data in all nodes produce the same, verifiable, consistent, and valid results in distributed systems, including blockchain technology. In a blockchain network, they guarantee that information remains consistent across all nodes. Leading vote-based consensus protocols such as Raft, although widely used, have various disadvantages and need improvement in some aspects. In particular, problems such as the fact that all responsibility lies with the leader node, reputation problems in nodes, and the existence of the possibility of Byzantine errors have led to improvement studies on the Raft consensus algorithm. Therefore, considering alternative consensus protocols, with their unique design features, contributes to current developments for academic circles, blockchain practitioners, and researchers and allows the field to advance. In this study, it is aimed to compare the improvement attempts on the Raft algorithm by performing performance analysis on the throughput and delay metrics of the X-RAFT, RE-RAFT, RR-RAFT and LRD-RAFT consensus algorithms based on the Raft consensus algorithm in a simulation to be created. The results to be obtained by measuring the performance of the newly developed consensus algorithms are intended to give an idea about the performance of vote-based consensus algorithms on blockchain networks. 

Keywords - blockchain, consensus protocol, raft, throughput, latency

Blokzincir teknolojileri, asimetrik şifreleme, hash algoritmaları, dağıtık yapı, akıllı sözleşmeler ve konsensüs mekanizmaları gibi kavramlara dayanır. Konsensüs mekanizmaları, blokzincir teknolojisi de dahil olmak üzere dağıtık sistemlerde, tüm düğümlerdeki verilerin aynı, doğrulanabilir, tutarlı ve geçerli sonuçlar üretmesini sağlayan yöntemlerdir. Bir blokzincir ağında, bilgilerin tüm düğümlerde tutarlı kalmasını garanti ederler. Raft gibi önde gelen oy tabanlı konsensüs protokolleri ise yaygın kullanılsalar da çeşitli dezavantajlar barındırmakta ve bazı yönlerden iyileştirmeye ihtiyaç duymaktadır. Özellikle tüm sorumluluğun lider düğüm üzerinde olması, düğümlerdeki itibar sorunları ve Bizans hata olasılığının varlığı gibi sorunlar, Raft konsensüs algoritması üzerinde iyileştirme çalışmalarına sebep olmuştur. Bu nedenle alternatif konsensüs protokollerinin ele alınması, sahip oldukları özgün tasarım nitelikleriyle, akademik çevreler, blokzincir alanındaki uygulayıcılar ve araştırmacılar için güncel gelişmelere katkı sağlamakta ve alanın ilerlemesine olanak tanımaktadır. Bu çalışmada, oluşturulacak bir simülasyon içerisinde, Raft konsensüs algoritması temelli X-RAFT, RE-RAFT, RR-RAFT ve LRD-RAFT konsensüs algoritmalarının verim, gecikme metrikleri üzerinde performans analizi yapılarak, Raft algoritması üzerindeki iyileştirme girişimlerinin karşılaştırılması amaçlanmaktadır. Geliştirilen yeni konsensüs algoritmalarının performans ölçümüyle elde edilecek sonuçlar, oy tabanlı konsensüs algoritmalarının blokzincir ağları üzerinde performans anlamında fikir vermesi amaçlanmaktadır.

Keywords^Turkish - blokzincir, konsensüs protokolü, raft, verim, gecikme

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