While several sophisticated scheduling strategies have been proposed to enhance performance of the Multipath Transport Control Protocol (MPTCP), most schedulers were implemented and evaluated before butter bloat optimizations have been introduced to the underlying Transport Control Protocol (TCP). Thus, the research question arises how these optimizations impact MPTCP performance across different scheduling strategies, and if a kernel-upgrade yields better results than changing the scheduler. To answer this question, we have upgraded several popular schedulers to the newer Linux kernel version 4, and conducted testbed measurements for different path rates and delays. Our data verifies that MPTCP indeed strongly benefits from the inherent TCP optimizations, so that the kernel upgrade often has a larger impact than a scheduler change. Thus, our findings indicate that the field of MPTCP scheduling must be revisited in the age of butter bloat optimizations.

This demo presents link ’em version 2, an open source modification of the Linux Network Emulator (netem), to enable trace-based loss and delay emulation of pre-recorded real-world network conditions. It is used in an experimental setup to demonstrate and evaluate the impact of Network Coding-based Forward Erasure Correction for TCP (TCPyNC) on the performance of Dynamic Adaptive Streaming over HTTP (DASH). Thus, the proposed demonstration showcases the novel features of link ’em v2 and highlights the capability of network coding-based FEC to improve the overall video quality and reduce stalling of DASH video streams.

Web traffic censorship limits the free access to information, making it a global human rights issue. The introduction of HTTP/3 (HTTP over QUIC) yields promising expectations to counteract such interference, due to its novelty, build-in encryption, and faster connection establishment. To evaluate this hypothesis and analyze the current state of HTTP/3 blocking, we extended the open-source censorship measurement-tool OONI with an HTTP/3 module. Using an input list of possibly-blocked websites, real-world measurements with HTTPS and HTTP/3 were conducted in selected Autonomous Systems in China, Iran, India, and Kazakhstan. The presented evaluation assesses the different blocking methodologies employed for TCP/TLS versus the ones employed for QUIC. The results reveal dedicated UDP blocking in Iran and major IP blocklisting affecting QUIC in China and India.

TCP still is the prevailing transport protocol on the Internet. It does, however, suffer from severe performance issues on links with non-congestion losses. Instead of relying on the RTT-sensitive ARQ mechanism of TCP, network coding (NC) uses linear combinations of packets to correct forward erasures. Several approaches were developed to incorporate NC into TCP. While they are able to improve the offered service, their lack of deployability and fairness in modern environments is not desirable. To mitigate this, we propose TCPyNC, a Python-based intra-session NC user space shim layer for TCP. Not only are its gains equally high, but it is also more flexible regarding the use of TCP options and parameters. We use a numerical analysis and a testbed evaluation to determine parameters that enable a fair use of TCP in conjunction with Forward Erasure Correction (FEC). In order to reach this goal, we found the maxim less is more to be a sensible orientation. For scenarios with 10% random loss, instead of choosing a high redundancy rate and a large generation size in order to gain the best loss reduction, choosing redundancy rates that leave between 1% and 6% loss for TCP’s ARQ to correct and generation sizes below 32 when using default TCP parameters, yields fair results.

Excessive padding overhead induced by packets of heterogeneous lengths is a critical problem when using network coding for real-world data in the wild. Current network coding schemes either use excessive zero-padding or communication-intensive packet reconstruction strategies, i.e. bundling or chaining. This paper presents novel encoding strategies to reduce the padding-induced overhead while preserving the original packet structures. The conducted evaluation is based on traces of datagram-based real-world applications, namely browsing via QUIC, Skype VoIP, FFmpeg video streaming, and UFTP file transfer. The results verify that the packet-preserving coding schemes can significantly reduce the overhead of transmitted bytes for different generation sizes and packet loss rates without the need for additional communication about packet reconstruction.

This paper presents an energy-efficient solution to overcome packet loss in Wireless Sensor Networks (WSNs) by adding seed-based Random Linear Network Coding to MQTT for Sensor Networks (MQTT-SN). Whereas most sensors integrated in common WSN devices consume little energy, using the radio is costly. To increase battery lifetime, devices try to minimize their radio uptime, while still satisfy timeliness and reliability of delivered data. The proposed approach uses an optimized seed-based intrasession Network Coding scheme for Forward Error Correction to shorten the sensor node's radio uptime, reducing its power consumption. The presented approach is conform to the MQTT-SN specification and, thus, interoperable with existing systems. Since the implementation is based on the application layer, it is seamlessly deployable via Over-The-Air-Programming. The presented evaluation is based on collected traces from a real-world WSN deployment in the context of Precision Agriculture. Radio uptime and power consumption measurements in an experimental testbed confirm the achieved benefits.

This paper presents a smooth way to include Network Coding in the Constrained Application Protocol (CoAP) for large resource transmissions. Devices in the Internet of Things usually communicate using short messages with little data. In some cases, for example, requesting firmware updates, bigger resources need to be transferred. CoAP's recently finalized blockwise transfer scheme can handle large resources, but is not efficient in lossy environments. Network Coding has proven to be more error resistant. This paper demonstrates the limitations of CoAP's existing blockwise transfer scheme and presents a new approach, based on Network Coding. The evaluation compares CoAP's regular blockwise transfer to the new Network Coding extension. Measurements on an implemented client-server application with simulated losses and delay, confirm the benefits of the extension, resulting in reduced transfer durations.