# Blockchain-Assisted QoS-Aware Routing for Software-Defined Wide Area Network
## 2 Related Work
\begin{table}
\begin{tabular}{c c c c} \hline
**Ref.** & **Target Problem** & **Methodology** & **Contribution** \\ \hline
[3] & Video streaming QoS over SDN & ARVS adaptive routing scheme & Prioritized rerouting for critical \\  & & & video packet layers \\ \hline
[4] & Delay-constrained unicast routing & DCUR distributed heuristic & Loop-free low-overhead \\  & & routing & delay-constrained routing \\ \hline
[5] & Probabilistic QoS routing under & Bayesian network-based & Bandwidth-aware probabilistic \\  & dynamic conditions & BaProbSDN & path selection \\ \hline
[6] & Multi-criteria optimal path & Pareto-optimal path set & Multi-metric routing in \\  & selection without predefined & discovery & demand-driven SDNs \\  & weights & & \\ \hline
[8] & Overhead in switch-based & QoS-aware flow management in & Proposed intelligent event-driven \\  & monitoring & SDN & monitoring \\ \hline
[9] & Trade-off between active and & Mathematical modeling and & Suggested passive monitoring for \\  & passive monitoring & experiments & low traffic variability \\ \hline
[10] & Heterogeneity in hybrid & Analysis of forwarding & Improved routing performance in \\  & SDN-legacy networks & strategies & hybrid SDN environments \\ \hline
[11] & Congestion and inefficient & Double Deep Q-Network & Real-time QoS-based path \\  & resource utilization in SDN & (DDQN) for QoS-aware routing & selection using DRL \\  & routing & & \\ \hline
[12] & QoS routing for IoT flows in SDN & \
\begin{tabular}{c} Machine learning classification \\  (MCCA2-RF\&RF) \\ \end{tabular} &
\begin{tabular}{c} Flow-specific multi-QoS routing \\ and local rerouting on congestion \\ \end{tabular} \\ \hline
[13] & QoS routing with load balancing & \
\begin{tabular}{c} Adaptive-weight based \\ Application-Aware QoS Routing \\ Algorithm (AQRA) \\ \end{tabular} &
\begin{tabular}{c} Multi-path selection maximizing \\ bandwidth and load balancing \\ \end{tabular} \\ \hline
[14] & Application-level QoS in SDN & NSAF framework with DiffServ & Dynamic QoS violation detection \\  & types & and path recovery \\ \hline
[15] & Improved OSPF performance in & Smart-OSPF enhanced routing & Aggregated traffic collection for \\  & hybrid SDN & & improved data transmission \\ \hline
[17] & Multi-constrained QoS routing & Bidirectional search strategy & Higher success rate and faster \\  & efficiency & & constraint satisfaction \\ \hline
[18] & Scalable dynamic routing in large & iPath incremental routing using & High-performance dynamic \\  & SDNs & Timely Dataflow & policy-driven routing \\ \hline \end{tabular}
\end{table} 
Table 1: Summary of related work. facilitating automatic payment processing. [PERSON] et al. [20] created an auctioning and trading framework by using smart contracts and cryptocurrency that ensures auction and trade fairness. Their framework ensures the accuracy of trade and auctioning computations and also suggests to each participant their next step at a specific state. Additionally, the framework connects the trade and auction processes with cryptocurrencies, ensuring participant fairness through a monetary penalty. The trading specifically achieves fair dealing with or without an arbitrator between the cloud provider and the cloud users. [PERSON] et al. [21] discussed an auction mechanism for federated cloud services that uses blockchain technology and allows numerous service providers to place winning bids. Two smart contracts were used in this model: one to control the auction process and another to enforce Service Level Agreements (SLAs) between customers and service providers. A new smart contract was also used to monitor the services offered by the providers in order to ensure SLA compliance and to pay for the service in accordance with their reports. In cases where the SLA is violated, penalties are applied. [PERSON] et al. [22] proposed a double auction-based cloud marketplace where sellers are cloud service providers who are giving their unused computing resources and purchasers are cloud service providers that need more computing power.