KauNet: A Versatile and Flexible Emulation System

This is a poster on the KauNet network emulation system. As compared to other emulation system, KauNet is deterministic. The poster shows how patterns enforce determinism and how patterns can be used to emulate a satellite channel at the IP level

Using Triggers for Emulation of Opportunistic Networking

Opportunistic networks do not require the availability of an end-to-end path, but may instead take advantage of tem- porary connectivity opportunities. Opportunistic networks pose a challenge for network emulation as the traditional em- ulation setup where application/transport endpoints send/ receive packets from the network following a black box approach is no longer applicable. Instead opportunistic networking protocols and applications need to react to the dynamics of the underlying network beyond what is conveyed through the exchange of packets. In order to support emulation evaluations for such challenging applications we in this paper introduce the concept of emulation triggers that can emulate arbitrary cross-layer feedback and that are synchronized with the emulated scenario. The design and implementation of triggers in the KauNet emulator are described. The use of triggers in the context of opportunistic networking is brie y sketched

IP-Level Satellite Link Emulation with KauNet

Distributed applications and transport protocols communicating over a satellite link may react very strongly to conditions specific to that kind of link. Providing a evaluation framework to allow tests of real implementations of such software in that context is quite a challenging task. In this paper we demonstrate how the use of the general-purpose KauNet IP-level emulator combined with satellite-specific packet loss patterns can help by reproducing losses and delays experienced on a satellite link with a simple Ethernet LAN setup. Such a platform is an essential tool for developers performing continuous testing as they provide new features for e.g. video codecs or transport-level software like DCCP and its congestion control components

A NEAT Way to do Network Programming

This work has received funding from the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 644334 (NEAT). The views expressed are solely those of the author(s)Peer reviewedPreprin

De-ossifying the Internet Transport Layer : A Survey and Future Perspectives

ACKNOWLEDGMENT The authors would like to thank the anonymous reviewers for their useful suggestions and comments.Peer reviewedPublisher PD

Low-Latency Scheduling in MPTCP

The demand for mobile communication is continuously increasing, and mobile devices are now the communication device of choice for many people. To guarantee connectivity and performance, mobile devices are typically equipped with multiple interfaces. To this end, exploiting multiple available interfaces is also a crucial aspect of the upcoming 5G standard for reducing costs, easing network management, and providing a good user experience. Multi-path protocols, such as multi-path TCP (MPTCP), can be used to provide performance optimization through load-balancing and resilience to coverage drops and link failures, however, they do not automatically guarantee better performance. For instance, low-latency communication has been proven hard to achieve when a device has network interfaces with asymmetric capacity and delay (e.g., LTE and WLAN). For multi-path communication, the data scheduler is vital to provide low latency, since it decides over which network interface to send individual data segments. In this paper, we focus on the MPTCP scheduler with the goal of providing a good user experience for latency-sensitive applications when interface quality is asymmetric. After an initial assessment of existing scheduling algorithms, we present two novel scheduling techniques: the block estimation (BLEST) scheduler and the shortest transmission time first (STTF) scheduler. BLEST and STTF are compared with existing schedulers in both emulated and real-world environments and are shown to reduce web object transmission times with up to 51% and provide 45% faster communication for interactive applications, compared with MPTCP's default scheduler

NEAT : A Platform- And Protocol-Independent Internet Transport API

ACKNOWLEDGMENT The authors would like to thank the anonymous reviewers for their useful remarks. This work has received funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 644334 (NEAT). The views expressed are solely those of the authors.Peer reviewedPostprin

Fast retransmit inhibitions for TCP

The Transmission Control Protocol (TCP) has been the dominant transport protocol in the Internet for many years. One of the reasons to this is that TCP employs congestion control mechanisms which prevent the Internet from being overloaded. Although TCP's congestion control has evolved during almost twenty years, the area is still an active research area since the environments where TCP are employed keep on changing. One of the congestion control mechanisms that TCP uses is fast retransmit, which allows for fast retransmission of data that has been lost in the network. Although this mechanism provides the most effective way of retransmitting lost data, it can not always be employed by TCP due to restrictions in the TCP specification. The primary goal of this work was to investigate when fast retransmit inhibitions occur, and how much they affect the performance of a TCP flow. In order to achieve this goal a large series of practical experiments were conducted on a real TCP implementation. The result showed that fast retransmit inhibitions existed, in the end of TCP flows, and that the increase in total transmission time could be as much as 301% when a loss were introduced at a fast retransmit inhibited position in the flow. Even though this increase was large for all of the experiments, ranging from 16-301%, the average performance loss, due to an arbitrary placed loss, was not that severe. Because fast retransmit was inhibited in fewer positions of a TCP flow than it was employed, the average increase of the transmission time due to these inhibitions was relatively small, ranging from 0,3-20,4%

Analys av trafiksäkerhetsutvecklingen 2023 : Målstyrning av trafiksäkerhetsarbetet mot etappmålen 2030

Det svenska trafiksäkerhetsarbetet utgår från Nollvisionen och etappmål på vägen dit. Det nuvarande etappmålet för vägtrafiken innebär en halvering av antalet omkomna, från 266 (medelvärde 2017–2019), till max 133 omkomna år 2030. Etappmålet innebär också att antalet allvarligt skadade i vägtrafiken ska reduceras med 25 procent utifrån ett motsvarande utgångsvärde. I denna rapport redovisas och analyseras utvecklingen av säkerheten i vägtrafiken utifrån utpekade indikatorer och antalet omkomna. Utöver beslutade natio-nella etappmål finns även ett etappmål på EU-nivå som innebär en halvering av antalet omkomna till 2030, jämfört med 2019