This paper tackles the problem of using and paying a network service with guaranteed quality of service (QoS) at a fine granularity in the future wireless network. We propose the IOTA-based QoS guaranteed Flow system (IQF), where a user and service provider can exchange the IOTA cryptocurrency for the guaranteed network resources, such as latency and bandwidth. First, IQF uses the IOTA Tangle, a lightweight, efficient distributed ledger technology, for its payment and transaction record. Second, IQF adopts Software Defined Networking to realize the guaranteed delay and bandwidth provision. We have implemented the IQF systems using the mininet-wifi emulator, an SDN controller (i.e., POX), and IOTA clients. Moreover, we have evaluated the service provisioning algorithms with a micropayment of IQF with the test Tangle (i.e., comnet). The evaluation results show that IQF has successfully achieved the delay and bandwidth provision with all the transactions stored in comnet.
Matthias Grundmann, Max Baumstark, Hannes Hartenstein
A recent spam wave of IP addresses in the Bitcoin P2P network allowed us to estimate the degree distribution of reachable peers in the network. The resulting distribution shows that about every second reachable peer runs with Bitcoin Core's default setting of a maximum of 125 concurrent connections and nearly all connection slots are taken. We validate this result and, in addition, use our observations of the spam wave to group addresses that belong to the same peer. By doing this grouping, we improve on previous measurements and show that simply counting addresses overestimates the number of reachable peers by 13 %.
Yustus Eko Oktian, Elizabeth Nathania Witanto, Sandra Kumi, Sang-Gon Lee
In general shared internet service, the ISP shares a static bandwidth resource pool to multiple customers in the same neighborhood area. The users' internet speed wavers when the number of customers accessing the same resource is increasing. The issue becomes problematic during peak hours. Many customers are expected to use the limited bandwidth simultaneously, thus deteriorating the overall user experiences. The ISP is subject to blame when such incidents happen; the customers claim the ISP breaks the Service Level Agreement by providing lower internet speed than the one the ISP marketed. It is a dilemma for the ISP, increasing the bandwidth resource pool may solve the problem. However, when the peak hours period is over, the additional bandwidth becomes useless, thereby generating the over-allocation problem. In this paper, we propose the use of blockchain and SDN to provide agile network bandwidth management for the ISP in the form of three use cases: Bandwidth on Demand, Selling Bandwidth, and Real-Time Pricing. We argue that using these proposed use cases, the ISP can serve the customer fairly, while also generating more appealing economics to compete in the modern market.
The goal of this research is to estimate the data propagation time on the Bitcoin network. Using network coordinates, we estimate the communication latency between computers. Such latency estimation contributes future optimization of data propagation. In this research, we report an experiment on computing the network coordinates. In the current Bitcoin network, it is very difficult to acquire internode delay because the network topology is not available. In this study, we calculate the delay based on our topology estimation and describe the effectiveness of the network coordinates using various topology estimation parameters.
The user can organize a social network together with other peoples, in the manner of the consortium blockchain, so that expected contents can be accessed via collecting pieces of data (sub-flows) from members. This promising mechanism heavily relies on the multipath data transmission to transfer sub-flows to the user over the social network. However, the performance differentiation and link overlapping of transmission paths between the user and members could result in severe traffic congestion and packet scrambling. To solve these problems, we design a novel SDN (Software-Defined Networking)-based framework because the global traffic engineering can perform more flexible flow transferring. Our SDN controller has three modules of topology discovery, sub-flow association and path selection. We quickly capture the social network from the most appropriate consortium blockchain where a set of paths with minimal link overlapping and performance differentiation can be found to transfer correlated sub-flows the user wants. The simulation results show that our solution achieves a higher network throughput compared with traditional methods while guaranteeing a low data retransmission rate.
The thesis investigates how a blockchain can be used to build a decentralised public key infrastructure for the web, by proposing a custom federation blockchain relying on honest majority. Our main contribution is the design of a Proof of Stake protocol based on a stake tree, which builds upon an idea called follow-the-satoshi used in previous papers. Digital identities are stored in an authenticated self-balancing tree maintained by blockchain nodes. Our back-of-the-envelope calculations, based on the size of the domain name system, show that the block size must be set to at least 5.2 MB, while each blockchain node with a one-month transaction history would need to store about 243 GB. Thin clients would have to synchronise about 13.6 MB of block headers per year, and download an additional 3.7 KB of proof data for every leaf certificate which is to be checked.