Аспекты практической реализации протокола ARTCP на ядре Linux 2.6

The article secifies the ARTCP header format and describes the algorithm of the ARTCP connection establishment. Some aspects of TCP and ARTCP interaction are discussed. Presented a work plan to implement the ARTCP in Linux.Уточняется формат заголовка ARTCP и описывается алгоритм установки ARTCP соединения. Рассмотрены некоторые вопросы взаимодействия TCP и ARTCP. Приведен план работ по реализации ARTCP в Linux

Формат пакета ARTCP. Особенности формирования и обработки заголовков ARTCP в сетевой подсистеме ОС Linux 2.6.

The article discusses an ARTCP header structure and some practical aspects of forming the header and the calculation of header fields. The questions of precise time dispatching of the received packets are discussed. The Linux kernel interfaces for time measurement are described as well as the clock source abstraction layer and its implementation.Описывается формат заголовка ARTCP. Рассматриваются практические аспекты формирования заголовка и вычисления значения его полей. Обсуждаются вопросы точного вычисления времени прибытия сегментов ARTCP. Также в статье описываются интерфейсы ядра Linux для вычисления времени и концепция "источников времени" и ее реализация

Enhancing Performance by Salvaging Route Reply Messages in On-Demand Routing Protocols for MANETs

Researchers prefer on-demand routing protocols in mobile ad hoc networks where resources such as energy and bandwidth are constrained. In these protocols, a source discovers a route to a destination typically by flooding the entire or a part of the network with a route request (RREQ) message. The destination responds by sending a route reply (RREP) message to the source. The RREP travels hop by hop on the discovered route in the reverse direction or on another route to the source. Sometimes the RREP can not be sent to the intended next hop by an intermediate node due to node mobility or network congestion. Existing on-demand routing protocols handle the undeliverable RREP as a normal data packet - discard the packet and initiate a route error message. This is highly undesirable because a RREP message has a lot at stake – it is obtained at the cost of a large number of RREQ transmissions, which is an expensive and timeconsuming process. In this paper, we propose the idea of salvaging route reply (SRR) to improve the performance of on-demand routing protocols. We present two schemes to salvage an undeliverable RREP. Scheme one actively sends a one-hop salvage request message to find an alternative path to the source, while scheme two passively maintains a backup path to the source. Furthermore, we present the design of two SRR schemes in AODV and prove that routes are loop-free after a salvaging. We conduct extensive simulations to evaluate the performance of SRR, and the simulation results confirm the effectiveness of the SRR approach

Evaluating the Effectiveness of IP Hopping via an Address Routing Gateway

This thesis explores the viability of using Internet Protocol (IP) address hopping in front of a network as a defensive measure. This research presents a custom gateway-based IP hopping solution called Address Routing Gateway (ARG) that acts as a transparent IP address hopping gateway. This thesis tests the overall stability of ARG, the accuracy of its classifications, the maximum throughput it can support, and the maximum rate at which it can change IPs and still communicate reliably. This research is accomplished on a physical test network with nodes representing the types of hosts found on a typical, corporate-style network. Direct measurement is used to obtain all results for each factor level. Tests demonstrate ARG classifies traffic correctly, with no false negatives and less than a 0.15% false positive rate on average. The test environment conservatively shows this to be true as long as the IP address change interval exceeds two times the network\u27s round-trip latency; real-world deployments may allow for more frequent hopping. Results show ARG capably handles traffic of at least four megabits per second with no impact on packet loss. Fuzz testing validates the stability of ARG itself, although additional packet loss of around 23% appears when under attack

ROUTING IN MOBILE AD-HOC NETWORKS: SCALABILITY AND EFFICIENCY

Mobile Ad-hoc Networks (MANETs) have received considerable research interest in recent years. Because of dynamic topology and limited resources, it is challenging to design routing protocols for MANETs. In this dissertation, we focus on the scalability and efficiency problems in designing routing protocols for MANETs. We design the Way Point Routing (WPR) model for medium to large networks. WPR selects a number of nodes on a route as waypoints and divides the route into segments at the waypoints. Waypoint nodes run a high-level inter-segment routing protocol, and nodes on each segment run a low-level intra-segment routing protocol. We use DSR and AODV as the inter-segment and the intra-segment routing protocols, respectively. We term this instantiation the DSR Over AODV (DOA) routing protocol. We develop Salvaging Route Reply (SRR) to salvage undeliverable route reply (RREP) messages. We propose two SRR schemes: SRR1 and SRR2. In SRR1, a salvor actively broadcasts a one-hop salvage request to find an alternative path to the source. In SRR2, nodes passively learn an alternative path from duplicate route request (RREQ) packets. A salvor uses the alternative path to forward a RREP when the original path is broken. We propose Multiple-Target Route Discovery (MTRD) to aggregate multiple route requests into one RREQ message and to discover multiple targets simultaneously. When a source initiates a route discovery, it first tries to attach its request to existing RREQ packets that it relays. MTRD improves routing performance by reducing the number of regular route discoveries. We develop a new scheme called Bilateral Route Discovery (BRD), in which both source and destination actively participate in a route discovery process. BRD consists of two halves: a source route discovery and a destination route discovery, each searching for the other. BRD has the potential to reduce control overhead by one half. We propose an efficient and generalized approach called Accumulated Path Metric (APM) to support High-Throughput Metrics (HTMs). APM finds the shortest path without collecting topology information and without running a shortest-path algorithm. Moreover, we develop the Broadcast Ordering (BO) technique to suppress unnecessary RREQ transmissions

Implementación Modular DCCP en Java.

En los últimos años los requerimientos de envío de la información por parte de las aplicaciones en el ámbito de la Internet se han diversificado significativamente. Los protocolos de transporte que se ha utilizado tradicionalmente para esos fines han sido TCP y UDP que son los encargados de proveer los mecanismos para la transferencia de los datos proporcionando cada uno un tipo de servicio diferente. Sin embargo, ninguno de los dos tipos de servicio provisto por estos protocolos se adapta satisfactoriamente a estos nuevos requerimientos de las aplicaciones de tiempo real. La carencia de mecanismos de control de congestión en UDP hace de este protocolo una opción aventurada. En este momento la única alternativa es usar el protocolo de transporte de TCP, que proporciona mecanismos de control de congestión, pero el mecanismo de nueva transmisión es una desventaja debido a la alta tardanza de punta a punta que esto causa. DCCP combina lo mejor de los dos protocolos dentro del contexto de transmisión de medios de comunicación, apoyando mecanismos de control de congestión sin nuevas transmisiones. Por estas y otras razones, se desarrollo un prototipo con las características del protocolo DCCP descrito en el [RFC 4340] al cual se le pueda agregar de manera clara y modular, la funcionalidad requerida, para evaluar su funcionamiento en condiciones reales, es decir, comunicando las dos partes del protocolo (“cliente-servidor”) a través de la Internet