Duplicating RTP streams

Packet loss is undesirable for real-time multimedia sessions but can occur due to a variety of reasons including unplanned network outages. In unicast transmissions, recovering from such an outage can be difficult depending on the outage duration, due to the potentially large number of missing packets. In multicast transmissions, recovery is even more challenging as many receivers could be impacted by the outage. For this challenge, one solution that does not incur unbounded delay is to duplicate the packets and send them in separate redundant streams, provided that the underlying network satisfies certain requirements. This document explains how Real-time Transport Protocol (RTP) streams can be duplicated without breaking RTP or RTP Control Protocol (RTCP) rule

TURTLE-P: a UML profile for the formal validation of critical and distributed systems

The timed UML and RT-LOTOS environment, or TURTLE for short, extends UML class and activity diagrams with composition and temporal operators. TURTLE is a real-time UML profile with a formal semantics expressed in RT-LOTOS. Further, it is supported by a formal validation toolkit. This paper introduces TURTLE-P, an extended profile no longer restricted to the abstract modeling of distributed systems. Indeed, TURTLE-P addresses the concrete descriptions of communication architectures, including quality of service parameters (delay, jitter, etc.). This new profile enables co-design of hardware and software components with extended UML component and deployment diagrams. Properties of these diagrams can be evaluated and/or validated thanks to the formal semantics given in RT-LOTOS. The application of TURTLE-P is illustrated with a telecommunication satellite system

Overview of evolved Multimedia Broadcast Multicast Services (eMBMS)

MBMS was introduced as a service to optimize the dissemination of common interest multimedia content. Recently, it evolved to eMBMS based on LTE-centered flexibilities. However, launch of eMBMS over LTE may support new services e.g. pushed content for M2M services and delivery of premium content to the users enjoying secured QoS. This document primarily focusses on the rules, procedures and architecture supporting MBMS based data exchanges, which have not seen any major changes since Release 9

Evaluating Mobility Pattern Space Routing for DTNs

Because a delay tolerant network (DTN) can often be partitioned, the problem of routing is very challenging. However, routing benefits considerably if one can take advantage of knowledge concerning node mobility. This paper addresses this problem with a generic algorithm based on the use of a high-dimensional Euclidean space, that we call MobySpace, constructed upon nodes' mobility patterns. We provide here an analysis and the large scale evaluation of this routing scheme in the context of ambient networking by replaying real mobility traces. The specific MobySpace evaluated is based on the frequency of visit of nodes for each possible location. We show that the MobySpace can achieve good performance compared to that of the other algorithms we implemented, especially when we perform routing on the nodes that have a high connection time. We determine that the degree of homogeneity of mobility patterns of nodes has a high impact on routing. And finally, we study the ability of nodes to learn their own mobility patterns.Comment: IEEE INFOCOM 2006 preprin

A real time demonstrative analysis of lightweight payload encryption in resource constrained devices based on mqtt

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Kısıtlı cihazların kaynakları, yani bellek (ROM ve RAM), CPU ve pil ömrü (varsa) sınırlıdır. Genellikle, veri toplayan sensörler, makinadan makineye (M2M) veya servisleri ve elektrikli ev aletlerini kontrol eden akıllı cihazlar için puanlar. Bu tür aygıtlar bir ağa bağlandığında "nesnelerin Internet'i" nin (IoT) bir parçasını oluştururlar. Message Queue Telemetry Transport (yani MQTT), hafif, açık, basit, istemci-sunucu yayın/abone mesajlaşma taşıma protokolüdür. Güvenilir iletişim için üç Hizmet Kalitesi (QoS) seviyesini destekleyen çoğu kaynak kısıtlamalı IoT cihazı için kullanışlıdır ve verimlidir. Cihazdan Cihaza (D2D) ve nesnelerin Internet'i (IoT) bağlamları gibi kısıtlı ortamlarda iletişim için gerekli olan bir protokoldür. MQTT protokolü, güvenli soket katmanı (SSL) sertifikalarına dayalı taşıma katmanı güvenliği (TLS) dışında somut güvenlik mekanizmalarından yoksundur. Bununla birlikte, bu güvenlik protokollerinin en hafif değildir ve özellikle kısıtlı cihazlar için ağ yüklerini artırır. IoT cihazlarının yaklaşık %70'inde özellikle de istemci tarafında veri şifrelemesi yoktur ve TLS için mükemmel bir alternatif olabilir. Bu tezde, farklı Hizmet Kalitesi (QoS) ve veri yüklerin değişken boyutu için kısıtlı bir cihaz üzerinde MQTT protokolünün ağ performansı üzerindeki etkisini göstermek için bir deney düzeneği tasarlanmıştır. Bu çalışmanın yeni kısmı, yüklerin istemci tarafında şifrelenmesini ve ağ performansı üzerindeki etkisini kapsıyor. Denemelerde, verilere 128-bits ileileri şifreleme standardı (AES) hafif bir şifreleme uygulanmıştır. Mesajlar, farklı yük boyutlarına dayanan bir komisyoncu sunucusu aracılığıyla gerçek kablolu alt uçtakı yayıncılık istemcisi ve düşük uçtakı abone istemcisi üzerinden MQTT'deki üç farklı QoS seviyesini kullanarak aktarılır. Paketler, şifreleme ve şifre çözme işlem süresinin ölçülmesiyle birlikte uçtan uca gecikme, verimlilik ve mesaj kaybı analiz etmek için yakalanır. Deney sonuçlarına göre, şifrelenmemiş (şifresiz metin) yükün daha düşük bir ağ yük etkisine sahip olduğu ve bu nedenle, yüzde kaybı ve mesaj tesliminde, şifreli yüke göre MQTT'yi kullanarak nispeten daha iyi bir ağ performansı ürettiği sonucuna varılmıştır.Constrained devices are limited in resources namely, memory (ROM and RAM), CPU and battery life (if available). They are often used as sensors that collects data, machine to machine (M2M) or smart devices that control services and electrical appliances. When such devices are connected to a network they form what is called "things" and in a whole, they form part of the "Internet of Things" (IoT). Message Queue Telemetry Transport (MQTT) is a common light weight, open, simple, client-server publish/subscribe messaging transport protocol useful and efficient for most resource constrained IoT devices that supports three Quality of Service (QoS) levels for reliable communication. It is an essential protocol for communication in constrained environments such as Device to Device (D2D) and Internet of Things (IoT) contexts. MQTT protocol is devoid of concrete security mechanisms apart from Transport Layer Security (TLS) based on Secure Socket Layer (SSL) certificates. However, this is not the lightest of security protocols and increases network overheads especially for constrained devices. About 70 % of most ordinary IoT devices also lack data encryption especially at the client-end which could have been a perfect alternative for TLS. In this thesis, an experimental setup is designed to demonstrate the effect on network performance of MQTT protocol on a constrained device for different Quality of Service (QoS) and variable size of payloads. The novel part of this study covers client-side encryption of payloads and its effect over network performance. In the experiments, a lightweight encryption of 128-bits Advanced Encryption Standard (AES) is applied on the data. The messages are transferred using the three different QoS levels in MQTT over real wired low-end publish client and low-end subscriber client via a broker server based on different payload sizes. The packets are captured to analyze end-to-end latency, throughput and message loss along with the measurement of encryption and decryption processing time. According to the results of the experiment, it was concluded that, non-encrypted (plaintext) payload have a lower network load effect and hence produces a relatively better network performance using MQTT in terms of percentage loss and message delivery than the encrypted payload

Secure Identification in Social Wireless Networks

The applications based on social networking have brought revolution towards social life and are continuously gaining popularity among the Internet users. Due to the advanced computational resources offered by the innovative hardware and nominal subscriber charges of network operators, most of the online social networks are transforming into the mobile domain by offering exciting applications and games exclusively designed for users on the go. Moreover, the mobile devices are considered more personal as compared to their desktop rivals, so there is a tendency among the mobile users to store sensitive data like contacts, passwords, bank account details, updated calendar entries with key dates and personal notes on their devices. The Project Social Wireless Network Secure Identification (SWIN) is carried out at Swedish Institute of Computer Science (SICS) to explore the practicality of providing the secure mobile social networking portal with advanced security features to tackle potential security threats by extending the existing methods with more innovative security technologies. In addition to the extensive background study and the determination of marketable use-cases with their corresponding security requirements, this thesis proposes a secure identification design to satisfy the security dimensions for both online and offline peers. We have implemented an initial prototype using PHP Socket and OpenSSL library to simulate the secure identification procedure based on the proposed design. The design is in compliance with 3GPP‟s Generic Authentication Architecture (GAA) and our implementation has demonstrated the flexibility of the solution to be applied independently for the applications requiring secure identification. Finally, the thesis provides strong foundation for the advanced implementation on mobile platform in future

Secure and Efficient Models for Retrieving Data from Encrypted Databases in Cloud

Recently, database users have begun to use cloud database services to outsource their databases. The reason for this is the high computation speed and the huge storage capacity that cloud owners provide at low prices. However, despite the attractiveness of the cloud computing environment to database users, privacy issues remain a cause for concern for database owners since data access is out of their control. Encryption is the only way of assuaging users’ fears surrounding data privacy, but executing Structured Query Language (SQL) queries over encrypted data is a challenging task, especially if the data are encrypted by a randomized encryption algorithm. Many researchers have addressed the privacy issues by encrypting the data using deterministic, onion layer, or homomorphic encryption. Nevertheless, even with these systems, the encrypted data can still be subjected to attack. In this research, we first propose an indexing scheme to encode the original table’s tuples into bit vectors (BVs) prior to the encryption. The resulting index is then used to narrow the range of retrieved encrypted records from the cloud to a small set of records that are candidates for the user’s query. Based on the indexing scheme, we then design three different models to execute SQL queries over the encrypted data. The data are encrypted by a single randomized encryption algorithm, namely the Advanced Encryption Standard AES-CBC. In each proposed scheme, we use a different (secure) method for storing and maintaining the index values (BVs) (i.e., either at user’s side or at the cloud server), and we extend each system to support most of relational algebra operators, such as select, join, etc. Implementation and evaluation of the proposed systems reveals that they are practical and efficient at reducing both the computation and space overhead when compared with state-of-the-art systems like CryptDB

Development of a Security-Focused Multi-Channel Communication Protocol and Associated Quality of Secure Service (QoSS) Metrics

The threat of eavesdropping, and the challenge of recognizing and correcting for corrupted or suppressed information in communication systems is a consistent challenge. Effectively managing protection mechanisms requires an ability to accurately gauge the likelihood or severity of a threat, and adapt the security features available in a system to mitigate the threat. This research focuses on the design and development of a security-focused communication protocol at the session-layer based on a re-prioritized communication architecture model and associated metrics. From a probabilistic model that considers data leakage and data corruption as surrogates for breaches of confidentiality and integrity, a set of metrics allows the direct and repeatable quantification of the security available in single- or multi-channel networks. The quantification of security is based directly upon the probabilities that adversarial listeners and malicious disruptors are able to gain access to or change the original message. Fragmenting data across multiple channels demonstrates potential improvements to confidentiality, while duplication improves the integrity of the data against disruptions. Finally, the model and metrics are exercised in simulation. The ultimate goal is to minimize the information available to adversaries