Ação e impacto de middleboxes presentes na world wide web / Impact and action of middlebox presence in the world wide web

Este trabalho visou investigar a ação de dispositivos, presentes em redes de computadores de forma geral, chamados middleboxes. Além disso a pesquisa visa trazer à luz, em forma de resultados, o impacto e a frequência de atuação desses dispositivos. A pesquisa se deu de forma ampla e global, avaliando diferentes modos de conexão, bem como testando a interação desses dispositivos com diversas características dos dados que trafegam na rede mundial de computadores.

Towards an incremental deployment of ERN protocols: a proposal for an E2E-ERN hybrid protocol

We propose an architecture based on a hybrid E2E-ERN approach to allow incremental deployment of ERN (Explicit Rate Notification) protocols in heterogeneous networks. The proposed IP-ERN architecture combines E2E (End-to-End)and ERN protocols and uses the minimum between both congestion windows to perform. Without introducing complex operation, the resulting E2E-ERN protocol provides inter and intra protocol fairness and benefits from all ERN protocol advantages when possible. We detail the principle of this novel IP-ERN architecture and show that this architecture is highly adaptive to the network dynamic and is compliant with IPv4, IPv6 as well as IP-in-IP tunneling solutions

Observing the Evolution of QUIC Implementations

The QUIC protocol combines features that were initially found inside the TCP, TLS and HTTP/2 protocols. The IETF is currently finalising a complete specification of this protocol. More than a dozen of independent implementations have been developed in parallel with these standardisation activities. We propose and implement a QUIC test suite that interacts with public QUIC servers to verify their conformance with key features of the IETF specification. Our measurements, gathered over a semester, provide a unique viewpoint on the evolution of a protocol and of its implementations. They highlight the arrival of new features and some regressions among the different implementations.Comment: 6 pages, 8 figure

Modeling a new Startup Algorithm for TCP New Reno

Peer reviewedPublisher PD

LEVANTAMENTO E MAPEAMENTO DA DISTRIBUIÇÃO DE MIDDLEBOXES PRESENTES NA WORLD WIDE WEB SURVEY AND MAPPING OF MIDDLEBOX DISTRIBUTION IN THE WORLD WIDE WEB

Este trabalho visou investigar a ação de dispositivos, presentes em redes de computadores de forma geral, chamados middleboxes. Além disso a pesquisa visa trazer à luz, em forma de resultados, o impacto e a frequência de atuação desses dispositivos. A pesquisa se deu de forma ampla e global, avaliando diferentes modos de conexão, bem como testando a interação desses dispositivos com diversas características dos dados que trafegam na rede mundial de computadores

MUST, SHOULD, DON'T CARE: TCP Conformance in the Wild

Standards govern the SHOULD and MUST requirements for protocol implementers for interoperability. In case of TCP that carries the bulk of the Internets' traffic, these requirements are defined in RFCs. While it is known that not all optional features are implemented and nonconformance exists, one would assume that TCP implementations at least conform to the minimum set of MUST requirements. In this paper, we use Internet-wide scans to show how Internet hosts and paths conform to these basic requirements. We uncover a non-negligible set of hosts and paths that do not adhere to even basic requirements. For example, we observe hosts that do not correctly handle checksums and cases of middlebox interference for TCP options. We identify hosts that drop packets when the urgent pointer is set or simply crash. Our publicly available results highlight that conformance to even fundamental protocol requirements should not be taken for granted but instead checked regularly

Peningkatan Performa Vertical Handover Pada Perangkat Bergerak Dengan Pengurangan Delay Pada Proses Deteksi Terputusnya Koneksi Berdasarkan Packet Inter-Arrival Timeout

Dewasa ini perangkat bergerak yang memiliki lebih dari satu network interface sudah menjadi hal yang biasa. Meskipun demikian, pada umumnya perangkat bergerak saat ini hanya memungkinkan penggunaan sebuah network interface saja setiap saat untuk terhubung ke internet. Ketika terjadi peralihan dari netwok interface yang satu ke network interface lain, diperlukan teknologi vertical handover untuk menjaga kualitas koneksi yang dirasakan oleh pengguna. Telah banyak penelitian yang dilakukan dan standar yang dibuat untuk mendukung handover pada data link layer dan network layer, namun belum ada standar untuk mendukung handover pada transport layer. Multipath TCP merupakan pengembangan TCP yang memungkinkan sebuah aplikasi pada sebuah host untuk menggunakan beberapa koneksi TCP sekaligus untuk berkomunikasi dengan host lain. Setiap koneksi TCP yang digunakan dalam Multipath TCP disebut sebagai subflow. Multipath TCP berpotensi memberikan dukungan handover yang baik pada transport layer bagi perangkat bergerak karena perubahan subflow yang digunakan dapat dilakukan secara transparan sehingga tidak menganggu kinerja aplikasi. Ketika sebuah subflow terputus akibat peralihan dari satu network interface ke network interface lain, Multipath TCP dapat beralih menggunakan subflow lain atau membuat subflow baru secara transparan sehingga tidak dirasakan oleh aplikasi. Untuk dapat melakukan vertical handover dengan cepat, perangkat bergerak harus dapat mendeteksi terputusnya sebuah subflow dengan cepat. Hal ini sulit dilakukan pada saat perangkat bergerak berperan sebagai penerima payload (receiver) tanpa mengirimkan payload ke host lain karena ia tidak dapat menggunakan mekanisme standar pada TCP untuk mendeteksi terputusnya subflow. Pada penelitian ini diajukan metode bagi host receiver untuk mendeteksi terputusnya subflow pada sebuah koneksi Multipath TCP berdasarkan packet inter-arrival timeout. Pada metode ini receiver menerima informasi adanya paket yang masih akan diterima, sehingga dapat memperhitungkan timeout untuk paket tersebut berdasarkan interval waktu antar paket yang telah diterima. Berdasarkan pengujian menggunakan simulator NS2 menunjukkan bahwa metode yang diajukan mampu mendeteksi terputusnya subflow dengan tingkat precision sebesar 0,944 pada jaringan dengan tingkat packet loss sebesar 0,1% atau kurang, dan juga menunjukkan bahwa pada jaringan dengan tingkat packet loss antara 0,1% hingga 1%, penggunaan metode yang diajukan menghasilkan pengurangan waktu deteksi terputusnya subflow sebesar rata-rata 310,82% round trip time jaringan dibandingkan dengan menggunakan retransmission timeout. =========================================================================================== Nowadays, multiple network interfaces have become a common feature in mobile devices. Despite of having multiple network interfaces, most of those mobile devices only allow single network interface to be used at a time for connecting to the internet. When the device decides to switch between network interfaces, vertical handover technology is needed to maintain connection quality for the user. Many researches have been done and standards have been created to support handover in data link layer and network layer, but no standard have been created to support handover in transport layer. Multipath TCP is a TCP extension that enables an application in a particular host to use several TCP connection to communicate with another host. Each of TCP connection used in Multipath TCP is called subflow. Multipath TCP holds great potential to provide good handover support in transport layer for mobile device because changes to subflow used can be done transparently so it will not disrupt application performance. When a subflow fails because of switchover between network interfaces, multipath TCP is able to switch to another subflow or create a new subflow transparently so this whole process is not visible to the application. To perform vertical handover quickly, mobile device must be able to quickly detect subflow failure. This may be a hard thing to do when mobile device acts as payload receiver without sending any payload to other host because it can not use mechanisms provided in standar TCP to detect subflow failure. This research propose a novel method for a receiver host to detect subflow failure in a Multipath TCP connection based on packet inter-arrival timeout. In this method, the receiver host is informed about the existence of packets it may receive later, so it can calculate timeout for the aforementioned packets based on existing packet inter-arrival time. Experiments using NS2 simulator in networks show that the proposed method were able to detect subflow failure with a precision of 0,944 for a network with packet loss rate of 0,1% or less, and also show the advantage of the proposed method in networks with packet loss rate of 0.1% - 1% yielding an average reduction in subflow failure detection delay of 310,82% of network round trip time compared to using standard retransmission timeout

Розробка та реалізація мережних протоколів. Навчальний посібник

Розробка та реалізація мережних протоколів важлива частина сучасної галузі знань, що необхідна для актуального забезпечення взаємозв’язку рівнів та різних технологій будь-якої локальної і глобальної мереж. Мережеві протоколи базуються на міжнародних стандартах, що забезпечують якісну взаємодію різних інноваційних технологій та різних елементів мережі. Вони складають семирівневу структуру, яка здійснює забезпечення вирішення інженерно-технічних питань та потребує постійно оновлювати, вдосконалювати та розробки нових протоколів, як правила взаємодії всіх складових глобальної мережі. Розробка та реалізація мережних протоколів потребує постійного розвитку та вдосконалення для надання абонентам високонадійних видів послуг з високошвидкісною передачею даних.The development and implementation of network protocols is an important part of the modern field of knowledge that is necessary for the actual interconnection of levels and different technologies of any local and global networks. Network protocols are based on international standards that ensure high-quality interaction of various innovative technologies and various network elements. They form a seven-tier structure that provides solutions to engineering and technical issues and requires constant updating, improvement and development of new protocols, as rules of interaction of all components of the global network. The development and implementation of network protocols requires constant development and improvement to provide subscribers with highly reliable types of services with high-speed data transmission.Разработка и реализация сетевых протоколов важная часть современной отрасли знаний, которая необходима для актуального обеспечения взаимосвязи уровней и различных технологий любой локальной и глобальной сетей. Сетевые протоколы базируются на международных стандартах, обеспечивающих качественное взаимодействие различных инновационных технологий и различных элементов сети. Они составляют семиступенчатая структуру, которая осуществляет обеспечение решения инженерно-технических вопросов и требует постоянно обновлять, совершенствовать и разрабатывать новые протоколы, как правила взаимодействия всех составляющих глобальной сети. Разработка и реализация сетевых протоколов требует постоянного развития и совершенствования для предоставления абонентам высоконадежных видов услуг по высокоскоростной передачей данных

Measuring Interactions between Transport Protocols and Middleboxes

In this paper we explore the current network environment with respect to how the network's evolution ultimately impacts end-to-end protocols. The traditional end-to-end assumptions about the Internet are increasingly challenged by the introduction of intermediary network elements (middleboxes) that intentionally or unintentionally prevent or alter the behavior of end-to-end communications. This paper provides measurement results showing the impact of the current network environment on a number of traditional and proposed protocol mechanisms (e.g., Path MTU Discovery, Explicit Congestion Notification, etc.). We present results of measurements taken using an active measurement framework to study web servers. We analyze our results to gain further understanding of the differences between the behavior of the Internet in theory versus the behavior we observed through measurements. In addition, these measurements can be used to guide the definition of more realistic Internet modeling scenarios