Low Earth Orbit (LEO) satellite networks are gaining prominence in 6G and large-scale IoT infrastructures, where traffic patterns range from low-rate telemetry to bandwidth-intensive applications such as high-resolution sensing, edge-assisted computation, and real-time vehicular services. Next-generation LEO constellations are designed to support high-capacity connectivity and heterogeneous IoT/6G services, some of which demand sustained high throughput and strict reliability guarantees. Multipath TCP (MPTCP) offers a transport-layer solution by enabling simultaneous use of multiple paths through concurrent subflows. This paper evaluates MPTCP version 1 in a LEO environment using bLEO , a new emulation tool for LEO networks specifically developed by the authors for this work. bLEO is an eBPF-based emulator capable of handling heavily loaded, large-scale constellations while providing efficient real-time control of link delay and state dynamics. We demonstrate MPTCP integration in Linux, including default scheduler behavior and subflow configuration. Additionally, we leverage Equal-Cost Multi-Path (ECMP) routing via OSPF using FRRouting to distribute MPTCP subflows across multiple network paths. The experimental results reveal a fundamental trade-off between robustness and scalability in the Linux MPTCP scheduler: although it maintains session continuity under handovers and failures, it underutilizes available paths unless load conditions force progressive subflow activation, reflecting a conservative design that prioritizes reordering avoidance and performance stability over full multipath utilization. The proposed platform serves as a flexible foundation for evaluating transport-layer protocols in dynamic satellite scenarios. • Evaluates the performance of Multipath TCP (MPTCP) in emulated LEO satellite networks with ECMP routing. • Integrates MPTCP with OSPF-based ECMP routing using FRRouting in a Linux environment. • Investigates subflow allocation and default scheduler behavior under dynamic LEO topologies. • Demonstrates how ECMP forwarding influences MPTCP path diversity and throughput in satellite networks.

The rapid expansion of Low-Earth-Orbit (LEO) satellite networks is critical for the advancement of beyond-6G (B6G) and IoT systems. However, the highly dynamic nature of LEO networks presents significant challenges for network protocols, including routing, handovers, and delay management. Existing LEO emulation tools struggle to efficiently scale to large constellations. In this paper, we present bLEO, a novel eBPF-based LEO network emulator designed to address these challenges. bLEO can emulate LEO constellations defined through configurable orbital parameters (e.g., number of orbital planes, number of satellites per plane, altitude, and inclination) and with dynamic inter-satellite and ground-satellite connectivity. Unlike traditional tools that rely on tc-netem , bLEO leverages eBPF to dynamically manage propagation delays and link states in real time. bLEO efficiently scales to thousands of satellites and ground stations while maintaining high performance through container-based virtualization and direct virtual Ethernet ( veth ) links. Our evaluation demonstrates that bLEO provides a scalable, accurate, and resource-efficient solution for testing protocols and applications in large-scale LEO networks.

ABSTRACT Background Low Earth Orbit (LEO) satellite constellations are redefining the concept of global connectivity, opening up a new world of opportunities for communication services and applications. Purpose The emergence of LEO satellites (SATs) is ushering in a new era of innovation, where new complex technologies are being developed, and the use of appropriate simulation environments is an essential part of this. LEO constellations promise low‐latency, high‐bandwidth Internet but require robust simulation tools due to their dynamic nature and the integration of numerous terrestrial and space nodes. Results In this paper, we review ns‐3‐based simulation frameworks widely referenced in relevant research work in the field of LEO constellation communications. We provide a technical overview, highlighting strengths and limitations, and offering valuable knowledge of the overall simulation tools for researchers focusing on high‐level end‐to‐end communication aspects over LEO constellations.

Network measurement provides rich data for network monitoring, control, and management. In-band network telemetry (INT) is a new network measurement technology that uses normal data packet to collect network information hop-by-hop. However, the design and implementation of INT protocol cannot do anything about packet loss: (1) The end-to-end telemetry mechanism makes INT unable to detect packet loss; (2) Since data packets may be lost due to various reasons, INT telemetry information will inevitably be lost. In summary, INT system by itself is unreliable. Incomplete telemetry data will seriously affect the performance of upper-layer network telemetry applications. In this paper, we present our successful experience in INT packet loss monitoring. We design, implement, and open source a powerful packet loss monitoring system for INT, called LossSight. The functions of LossSight include the detection of packet loss events, the deduction of the time and location of the losses, the diagnose of the root cause of the losses, and the recovery of the lost INT information. Experiment results show that LossSight provides excellent performance and extremely low overhead, including detection accuracy and diagnostic precision close to 100%, and detection latency of just milliseconds. In particular, LossSight uses a generative adversarial network to recover lost telemetry information, with excellent accuracy and reliability. LossSight has been running stably in the supercomputing interconnection environment of the National Supercomputing Center in Jinan. We suggest that all INT applications that require reliable telemetry information should be implemented based on LossSight.

Nowadays, monitoring per-flow metrics, such as throughput and delay, in OpenFlow networks represents an important input to implement traffic engineering approaches. Per-flow monitoring mechanisms require to uniquely identify the complete network path followed by all the packets of the corresponding flow. For example, in order to measure path delay, monitoring mechanisms regularly inject probe packets at the first switch of the path, such that these packets travel exactly along the same path of the corresponding flow till the last switch, which is in charge of sending them back to the network controller to compute the path delay. However, while a flow is active, any of the switches of the corresponding path can suffer different kinds of failure. In this situation, a new path must be recomputed for this flow by the controller in a timely manner, and the monitoring tool must be also updated. In this paper we present a mechanism which improves the behavior of per-flow monitoring modules allowing them to react in the face of network failures.

In this work, a network simulator for power line communications based in the Homeplug-AV technology is presented. The simulator implements both the physical and the MAC layers, along with an in-home power line channel generator, which makes it very useful in a wide variety of network optimization procedures. To the authors' knowledge, performance evaluation of the MAC layer of Homeplug-AV by means of simulations has been always accomplished assuming excessively simplistic channel conditions. Therefore, this simulator represents an important contribution, as it includes a realistic physical model along with the CSMA/CA protocol described in the standard. In this paper, the proposed simulator is employed to evaluate the performance of the Homeplug-AV standard in an in-home network. The obtained results are then applied to video services planning in networks based in this standard.

In this paper, we analyze a multicast protocol called MUST (multicast synchronous transfer), which offers multicast file transfer service to the application layer, in an intracampus environment (several interconnected LAN networks). Synchronicity is one of its more remarkable attributes since MUST guarantees that all clients are receiving the information at the same time. For an efficient bandwidth utilization, MUST transmits IP packets by using multicast addressing. Also, it achieves a notable acknowledgement packets reduction by an appropriate mechanism. Flow control and error recovery algorithms are also developed to satisfy features such as reliability, high throughput and low delay. To evaluate the protocol, we first implemented an application based on it that we extensively tested in a lab with up to ten computers in an intracampus environment. Then, we also developed a mathematical model validating analytically the most important protocol parameters. The methodology used to study this multicast protocol is in fact another contribution and can be extrapolated easily to other protocols.

In this paper, we study a multicast transport protocol called MUST (multicast synchronous transfer), which offers multicast synchronous file transfer service to the application layer, in an intra-campus environment. For an efficient bandwidth utilization, MUST transmits IP packets by using multicast addressing. Also, it achieves a notable acknowledgement packets reduction by an appropriate mechanism. Flow control and error recovery algorithms are also developed to satisfy features such as reliability, high throughput and low delay. We present in this work some test results of the protocol transfer delay, some flow control features and the UDP buffer overflow probability (this last parameter is also verified by simulation). We also compare the experimental and simulation results with a mathematical model, validating analytically the most important protocol parameters.

The MPEG-21 vision is to define a multimedia framework to enable transparent and augmented use of multimedia resources across a wide range of networks and devices used by the different communities. This paper describes the evolution of a test bed simulating an MPEG-21 framework considering a streaming media use case scenario. The test bed has been set up in order to realize, validate and perform experimentations on streaming media considering the integration of MPEG-4 content representation and MPEG-7 audiovisual content description interface within the MPEG-21 multimedia framework. The application scenario is within the concept of universal multimedia access (UMA) realizing the challenge of "create once play any time, any how, any where".