Direct Acyclic Graph based Ledger for Internet of Things: Performance and Security Analysis

Direct Acyclic Graph (DAG)-based ledger and the corresponding consensus algorithm has been identified as a promising technology for Internet of Things (IoT). Compared with Proof-of-Work (PoW) and Proof-of-Stake (PoS) that have been widely used in blockchain, the consensus mechanism designed on DAG structure (simply called as DAG consensus) can overcome some shortcomings such as high resource consumption, high transaction fee, low transaction throughput and long confirmation delay. However, the theoretic analysis on the DAG consensus is an untapped venue to be explored. To this end, based on one of the most typical DAG consensuses, Tangle, we investigate the impact of network load on the performance and security of the DAG-based ledger. Considering unsteady network load, we first propose a Markov chain model to capture the behavior of DAG consensus process under dynamic load conditions. The key performance metrics, i.e., cumulative weight and confirmation delay are analysed based on the proposed model. Then, we leverage a stochastic model to analyse the probability of a successful double-spending attack in different network load regimes. The results can provide an insightful understanding of DAG consensus process, e.g., how the network load affects the confirmation delay and the probability of a successful attack. Meanwhile, we also demonstrate the trade-off between security level and confirmation delay, which can act as a guidance for practical deployment of DAG-based ledgers.Comment: accepted by IEEE Transactions on Networkin

PEMODELAN, SIMULASI, DAN ANALISIS PENERAPAN QUALITY OF SERVICE (QOS) PADA IP MULTIMEDIA SUBSYSTEM (IMS) DENGAN MENGGUNAKAN DIFFSERV DI JARINGAN UNIVERSAL MOBILE TELECOMMUNICATION SYSTEM (UMTS)

ABSTRAKSI: Penerapan Quality of Service (QoS) pada IP Multimedia Subsystem (IMS) dengan Differentiated Services (DiffServ) di jaringan UMTS menyebabkan timbulnya dimensi yang baru pada jaringan secara keseluruhan, karena biasanya DiffServ ini diterapkan untuk pengelolaan QoS dalam jaringan IP. DiffServ merupakan IP based QoS yang membagi trafik atas kelas-kelas layanan dan memperlakukan setiap kelas secara berbeda. Kelas-kelas layanan ini dirancang sesuai dengan Per Hop Behavior Grup (PHB) untuk DiffServ yang telah distandarisasi oleh Internet Engineering Task Force (IETF) [1].Pada penelitian ini dilakukan pemodelan trafik dan interworking jaringan akses WLAN dengan jaringan core UMTS, IMS, dan server aplikasi, terkait dengan kelas-kelas layanan yang terdiri dari conversational, interactive, dan background. Model-model tersebut dikombinasikan dengan perubahan jumlah user, penerapan QoS menggunakan DiffServ, dan lokasi user baik yang roaming maupun yang berada di home network untuk dilihat dampaknya terhadap end-to-end delay, jitter, response time, dan throughput.Hasil simulasi menunjukkan bahwa pertambahan jumlah user, penerapan QoS menggunakan DiffServ, dan lokasi user baik yang roaming maupun yang berada di home network mempengaruhi perubahan nilai end-to-end delay, jitter, response time, dan throughput.Kata Kunci : NGN, IMS, QoS, Diffserv, dan UMTSABSTRACT: IP Multimedia Subsystem (IMS) emerge within the concept of multimedia, mobile and data communication. IMS is the international standard which is promoted by Third Generation Partnership Project (3GPP) Release 5, acts as an control domain for multimedia services in third generation mobile system or commonly known as Universal Mobile Telecommunication System (UMTS).The implementation of Quality of Service (QOS) in IMS using Differentiated Services (DiffServ) in UMTS network will create a new dimension in networking as a whole, for DiffServ is usually implemented in IP network QOS management. DiffServ is an IP based QoS which differentiate traffic into several service classes and treat each and every one of them differently. These service classes are designed in accordance to Per Hop Behavior (PHB) Group for DiffServ which is standardized by Internet Engineering Task Force (IETF) [1].This research will analyze the traffic modeling and WLAN access interworking with UMTS core network, IMS, and application server, related to the service classes such as conversational, interactive, and background. These models will combined with the increase of users, DiffServ Implementation, and the change of user location, including roaming and home network which will be impacted the change of end-to-end delay, jitter, response time, and throughput.The simulation results show us that the increase of users, DiffServ Implementation, and the change of user locations, including roaming and home network, force the change of end-to-end delay, jitter, response time, and throughput.Keyword: NGN, IMS, QoS, Diffserv, and UMT

Flexible functional split and fronthaul delay: a queuing-based model

We study the delay over virtual RAN (vRAN) topologies, entailing base stations that are divided into centralized and distributed units, as well as the packet-switched fronthaul network that connects them. We consider the use of flexible functional split, where the functions that are executed at each of these two entities can be dynamically shifted. We propose a queuing-based model, which is able to precisely mimic the behavior of such nodes, and we validate it by means of extensive simulations. We also exploit Jackson Networks theory to establish the end-to-end delay over the fronthaul network, allowing us to assess the impact of having different networking policies and conditions (for instance, background traffic or heterogeneous technologies). Thanks to the simulator we can also broaden the analysis, by studying the delay variability. In addition, we conduct an in-depth analysis of the performance exhibited by a realistic network setup, whose particular characteristics might hinder the services performance, due to the longer dwell times at each split configuration. The results evince the validity of the proposed model, even under realistic conditions. We show that it might not be enough to guarantee an average stable operation of the centralized/distributed units, but the traffic load should remain below the slowest service rate, to avoid reaching unacceptable delays. An increase of >100× is observed in the delay, using the realistic network setup, when these conditions do not hold.This work was supported in part by the Spanish Government, Ministerio de Economía y Competitividad, Fondo Europeo de Desarrollo Regional (MINECO-FEDER), through the Project FIERCE: Future Internet Enabled Resilient smart CitiEs under Grant RTI2018-093475-AI00; and in part by the European Research Council (ERC) under the European Union’s Horizon 2020 Research and Innovation Program (FlexNets) under Grant 64715

Analisa dan Implementasi Session Initiation Protocol dan<br /> Real-Time Transport Protocol Pada Telephony Over<br /> Internet Protocol<br /> Analisys and Implementation of Session Initiation<br /> Protocol and Real-Time Transport Protocol to Telephony<br

ABSTRAKSI: SIP (Session Initiation Protocol) ialah protokol kontrol sinyal pada application layer yang membentuk, memodifikasi, dan menghentikan sesi multimedia seperti internet multimedia conferences, internet telephone calls, dan multimedia distribution. Protokol SIP merupakan protokol berbasis teks dan dapat dikembangkan dengan fitur dan layanan tambahan seperti layanan pengontrolan panggilan dan ketersediaan user, instant messages, mobility, dan interoperability dengan sistem telephony. Adanya teknologi ini diharapkan dapat memenuhi kebutuhan akan koneksi panggilan ke berbagai wilayah selama masih dalam cakupan jaringan internet. Protokol RTP (Real-Time Transport Protocol) membentuk fungsi yang tepat pada transportasi jaringan end-to-end system untuk aplikasi transmisi data real-time seperti audio, video, dan data simulasi melalui layanan jaringan multicast atau unicast. Penerapan Session Initiation Protocol sebagai protokol kontrol pensinyalan dan Real-Time Transport Protocol sebagai protokol yang mengatur pengiriman media pada system yang akan diimplementasikan. Penggunaan teknologi Internet Telephony dengan menggunakan protokol SIP dan RTP dintegrasikan dengan sistem administrasi akan lebih praktis dalam proses pembangunan dan pemeliharaan aplikasi tersebut. Analisis pada SIP dan RTP dilakukan dengan mengaplikasikan penggunaan Type of Service dan codec yang digunakan oleh klien dalam melakukan koneksi pada system sehingga akan didapat behavior pesan dan call flow SIP dan delay, jitter, dan konsumsi bandwidth pada RTP.Kata Kunci : Internet Telephony, SIP, RTP, linux.ABSTRACT: The Session Initiation Protocol is an application layer control signaling protocol for creating, modifying and terminating sessions, these include internet multimedia conferences, internet telephone calls and multimedia distribution. SIP is text-based protocol and can be developed with additional feature and service, these include call control service, presence, instant messages, mobility, and interoperability with other telephony system. This technology can fulfilled the needed of call connection to other area in internet coverage. The Real-time Transport Protocol provides end-to-end network transport functions suitable for applications transmitting real-time data such as audio, video or simulation data, over multicast or unicast network services. By using Session Initiation Protocol for control signaling protocol and RTP for controlling media transport on a system that will be implemented. Internet Telephony technology with SIP and RTP will be integrated with administration system will be more effective in the building and maintenance of the system. Analize processing to SIP and RTP with using of type of service and codecs that used by client in order to connecting to the system so it can be obtain SIP message behavior and call flow and RTP delay, jitter, and bandwidth compsumptions.Keyword: Internet Telephony, SIP, RTP, linux

Game-Theoretic Relay Selection and Power Control in Fading Wireless Body Area Networks

The trend towards personalized ubiquitous computing has led to the advent of a new generation of wireless technologies, namely wireless body area networks (WBANs), which connect the wearable devices into the Internet-of-Things. This thesis considers the problems of relay selection and power control in fading WBANs with energy-efficiency and security considerations. The main body of the thesis is formed by two papers. Ideas from probability theory are used, in the first paper, to construct a performance measure signifying the energy efficiency of transmission, while in the second paper, information-theoretic principles are leveraged to characterize the transmission secrecy at the wireless physical layer (PHY). The hypothesis is that exploiting spatial diversity through multi-hop relaying is an effective strategy in a WBAN to combat fading and enhance communication throughput. In order to analytically explore the problems of optimal relay selection and power control, proper tools from game theory are employed. In particular, non-cooperative game-theoretic frameworks are developed to model and analyze the strategic interactions among sensor nodes in a WBAN when seeking to optimize their transmissions in the uplink. Quality-of-service requirements are also incorporated into the game frameworks, in terms of upper bounds on the end-to-end delay and jitter incurred by multi-hop transmission, by borrowing relevant tools from queuing theory. The proposed game frameworks are proved to admit Nash equilibria, and distributed algorithms are devised that converge to stable Nash solutions. The frameworks are then evaluated using numerical simulations in conditions approximating actual deployment of WBANs. Performance behavior trade-offs are investigated in an IEEE 802.15.6-based ultra wideband WBAN considering various scenarios. The frameworks show remarkable promise in improving the energy efficiency and PHY secrecy of transmission, at the expense of an admissible increase in the end-to-end latency