Seminar: Moderne Internettechnologien

The IEEE 802.11be standard introduces Multi-Link Operation (MLO), which enables devices to operate concurrently over multiple channels, either within or across frequency bands. By distributing traffic over these parallel links, MLO reduces latency and congestion on any single channel while increasing total throughput. Consequently, MLO improves the reliability and efficiency of IEEE 802.11be networks.

Ziele der Seminararbeit:
• Explain the MLO technique in IEEE 802.11be
• A literature review on the real-world performance evaluation of MLO

Vehicle-to-Everything (V2X) communication enables vehicles to wirelessly exchange real-time information with their entire environment, including other cars, traffic lights, and pedestrians. However, this technology faces a unique challenge: cars are constantly moving, making traditional internet routing (like using fixed IP addresses) too slow and unreliable for fast-paced traffic. To solve this, the European Telecommunications Standards Institute (ETSI) created a specialized approach for Intelligent Transport Systems (ITS) called GeoNetworking.

Unlike conventional networking, GeoNetworking routes data packets based on geographical coordinates and areas rather than network addresses. This spatial approach allows vehicles to efficiently disseminate critical, time-sensitive information—such as hazard warnings or cooperative awareness messages—to all relevant recipients within a specific physical area (GeoBroadcast). Understanding the technical mechanics of this protocol is essential for implementing reliable, low-latency V2X applications in real-world traffic scenarios.

Ziele der Seminararbeit:
• Provide a technical overview of the ETSI ITS station architecture and the specific role of the GeoNetworking layer.
• Explain core geographical routing mechanisms and addressing schemes, such as GeoBroadcast, GeoUnicast, and Topologically-Scoped Broadcast.
• Analyze the technical challenges of GeoNetworking, including managing high vehicular mobility, dynamic network changes, and efficient data dissemination.

The increasing number of connected devices in the Internet of Things requires wireless communication technologies that support long transmission ranges while maintaining low energy consumption. Many traditional wireless technologies, such as Wi-Fi or Bluetooth, are designed for short-range, high-throughput communication and are therefore not well suited for large-scale sensor deployments. Low-power wide-area network (LPWAN) technologies address this challenge by enabling long-distance communication with minimal energy usage. One of the most prominent technologies in this domain is LoRa.

Ziele der Seminararbeit:
• Comprehensive review of relevant literature and technical documentation on the LoRa wireless communication technology and its use in IoT systems.
• Describe the fundamental principles of LoRa communication, including its modulation scheme and its integration within the LoRaWAN network architecture.
• Discuss how configuration parameters such as spreading factor, bandwidth, and coding rate, as well as transmission power and data rate influence communication range, reliability, energy consumption, and network capacity.
• Discuss advantages and limitations of LoRa-based communication.
• Describe typical application scenarios.

Wireless communication is crucial for enabling connectivity between devices in smart home and IoT environments. These systems often consist of numerous small devices with limited computational resources and energy budgets, requiring communication protocols that are both efficient and scalable. Zigbee is a widely used wireless technology designed specifically for such low-power, low-data-rate applications and supports mesh networking, thereby extending the communication range and improving network robustness.

Ziele der Seminararbeit:
• Review of relevant standards and scientific literature on the architecture and communication mechanisms of Zigbee networks.
• Describe the different roles of devices in a Zigbee network, including coordinators, routers, and end devices, and explain how these components interact to form a mesh network.
• Analyze how Zigbee networks manage device discovery, routing, and message forwarding. Give particular attention to the routing mechanisms and processes by which messages are transmitted across multiple nodes to reach their destination.
• Discuss advantages and limitations of Zigbee in smart home and IoT environments.

Wireless Local Area Networks (WLANs) based on the IEEE 802.11 standard are very important for mobile devices, as this is the only way they can access the network and finally the Internet. Typically, many devices are connected to the same WLAN and use it at the same time. Therefore, a Media Access Control (MAC) protocol is necessary for coordinating access to the shared medium.

Ziele der Seminararbeit:
• Why can the MAC protocol of IEEE 802.3 networks not be used in IEEE 802.11 networks?
• Explain DCF und PCF in detail
• Explain Quality of Service improvements (IEEE 802.11e)

For large web companies and Content Distribution Networks the performance and security of web protocols is of big concern. Out of this reasons Google proposed the QUIC protocol. All mobile apps from Google support QUIC and in October 2020 more than 75% of the Meta internet traffic uses QUIC making it to the standard internet protocol at Meta [1].

How does this upcoming protocol ensure security? How is the higher performance achieved and how much higher is it? What is the Packet Pacing, which is used in QUIC and why can it be beneficial compared to techniques used in TCP (e.g. Fast Retransmit)?

Goals of the seminar paper:

• Explain the QUIC protocol

• Compare it with the TCP protocol variants

• Write about performance measurements and experiences with the QUIC protocol.

Federated Learning is a machine learning setting, where many clients train together without making the data itself accessible for the collaborators. This enables many institutions with smaller datasets to gain insights they couldn’t get with just their own data. Also, in privacy restricted areas like medical data Federated Learning could help.

With the evolving mobile communication technologies edge computing theory and techniques have been attracted an increasing interest of researchers and engineers around the world. Edge computing can help to accelerate content delivery and reduce network load, by communicating with near edge nodes instead of the cloud. This leads to new problems like task scheduling, data replication and data placement.

Ziele der Seminararbeit:
• Describe challenges for Federated Learning especially in edge networks.
• Explain how some Federated Learning approaches tackle these challenges.
• Compare the results of approaches that take these challenges into account with results of standard Federated Learning approaches.

Modern cloud applications are characterized by their global distribution and the need to serve millions of concurrent users. To manage this complexity and ensure scalability, these applications often move away from monolithic designs toward microservice architectures. In such environments, the overall functionality of a system emerges from the interaction of hundreds or even thousands of individual, decoupled components. This shift has placed a renewed focus on efficiency and reliability of inter-service communication.

While REST-based APIs (typically using HTTP/1.1 and JSON) have long been the industry standard, they often introduce overhead that can become a bottleneck in high-throughput, low-latency cloud environments. As a result, Remote Procedure Calls (RPC) have seen a resurgence. In particular, the gRPC framework—leveraging Protocol Buffers for serialization and HTTP/2 for transport—has emerged as a powerful alternative.

Ziele der Seminararbeit:
• Fundamentals: What is the underlying paradigm of RPC, and how does it differ from resource-oriented architectures like REST?
• Technology Stack: How does a modern framework like gRPC work? Discuss the role of Interface Definition Languages (IDLs), code generation, and the advantages of the binary Protocol Buffer format.
• Performance & Scalability: How does RPC perform in cloud-native applications? Analyze performance characteristics (at scale), either through a comparison with REST-based communication or through a survey of different RPC frameworks (e.g., gRPC, ONC RPC, WebRPC, etc.) and their respective trade-offs.

The Internet was originally designed to connect systems reliably and indiscriminately, routing traffic seamlessly around disruptions. However, the modern reality diverges significantly from this vision. As the web grew, network operators introduced firewalls and segregated networks to defend against malicious actors.

Yet, the very same technologies designed to protect private networks have been co-opted on a massive scale. Today, various jurisdictions heavily diverge on what they consider appropriate or legal. This has led to a rise in state-level and organizational interference, with authorities deploying sophisticated network security tools as censorship mechanisms to impede their citizens' access to global communication and content.

Ziele der Seminararbeit:
• Censorship Mechanisms: Give a structured overview of modern, network-level censorship techniques. How do wardens (censors) influence access to online resources?
• Measurement Methodologies: How do researchers detect blockages without being physically present in the censored region?
• Limitations and Evasion: Give a brief overview of popular technologies (e.g., VPNs, Tor, etc.) that can be used to bypass regional restrictions.

Tor is a popular anonymity network that allows users to browse the Internet without revealing their true identity, location, or activity. By routing Internet traffic through a series of encrypted nodes or relays, the source of the traffic is obscured and user privacy is maintained.

Ziele der Seminararbeit:
• Provide a comprehensive overview of Tor and its technical underpinning by exploring how Tor works internally and how it achieves privacy.
• Review the potential risks and limitations of Tor.
• Discuss the impact of Tor on Internet privacy and security.

I2P is a self-contained network that ensures secure and anonymous communication between users. Unlike other anonymity networks, I2P focuses on providing a private communication layer within its own boundaries, rather than enabling access to the wider Internet. In this seminar topic, we will explore the pivotal role of I2P in the realm of anonymous online communication

Ziele der Seminararbeit:
• Navigate through the key points of the I2P architecture.
• Discuss the use of garlic routing to encrypt and bundle messages.
• Examine the various applications intrinsic to the I2P ecosystem.
• Analyze the network's limitations and vulnerabilities.

A person's eye movements can be used as a control mechanism, to design adaptive interfaces that respond to the user's current state to dynamically offer support, or as an alternative authentication method. In order to extract meaningful information from gaze data, sophisticated algorithms are used that require considerable amounts of computational power. Typically, the raw gaze data is therefore sent to powerful servers, often over unsecure networks. As the gaze is classified as highly sensitive biometric data, this transmission imposes a significant threat to security and privacy. While local preprosessing of the gaze data (e.g., differential privacy approaches) can mitigate some of these concerns, they are typically not suitable when gaze is used for authentication purposes.

Ziele der Seminararbeit:
• Review approaches that have been proposed in scientific literature to ensure the safe transmission of gaze data while maintaining the identifiable features in the data that are necessary for gaze-based authentication.
• Compare the identified approaches in terms of the strength of the security that they promise, as well as their remaining risks and potential drawbacks.
• Discuss the applicability of the approaches in different contextual settings.

The automotive industry is increasingly shifting from hardware-centric architectures towards software defined vehicles (SDVs), where features and functions are primarily enabled und updated through software. Over the years, SDV architectures have evolved from a distributed to a centralized model in order to better accommodate emerging technologies and new requirements of modern vehicles.

Ziele der Seminararbeit:
• Systematically compare the predominant software-defined vehicle architectures and characterize how they have evolved over time.
• Discuss the current state of industry and academic research.
• Identify the advantages and challenges of the reviewed vehicle architectures.

Typical IoT devices are often resource constrained and cannot tolerate the computational overhead of TCP/IP + HTTP + REST. CoAP aims to provide a more light-weight alternative for such platforms. [1]

Ziele der Seminararbeit:
• Motivate the usage of CoAP in resource-constrained environments.
• Provide a technical introduction to CoAP, including the underlying message format and protocols (e.g., for service discovery).
• Discuss trade-offs and limitations of CoAP (e.g., regarding security guarantees).

DECT NR+ is a non-cellular 5G technology standard that specializes on ultra-high reliability and ultra-low latency (>99.99% reliability at sub-millisecond latencies). This seminar topic aims to provide a technical introduction to the central DECT NR+ mechanisms that enable such guarantees.

[1] ETSI TS 103 636-1, DECT-2020 New Radio (NR); Part 1: Overview

Ziele der Seminararbeit:
• Motivate the usage of DECT NR+ compared to public/private 5G deployments.
• Provide a technical introduction to DECT NR+, including its physical layer and media access control (MAC) layer.
• Discuss potential applications and technical limitations of DECT NR+.

Real-time communication with deterministic bounds on network delay and jitter is crucial for the efficient and safe operation of networked real-time systems. As distributed Cyber-Physical Systems (CPSs) with networked sensors, actuators, and controllers become increasingly popular in various domains such as Industrial Internet of Things (IIoT) and autonomous vehicles, the demand for deterministic real-time communication with a high reliability and bounded network delay and delay variance (jitter) has grown.

Major standardization organizations like the Institute of Electrical and Electronics Engineers (IEEE) and the Internet Engineering Taskforce (IETF) have acknowledged the necessity for deterministic networks leading to a set of standards under the term Time-Sensitive Networking (TSN), which extend standard wired IEEE 803.3 networks (Ethernet) by real-time communication mechanisms. For example, IEEE 802.1Qbv defines the Time-Aware Shaper, which enables deterministic scheduling of traffic through time-slotting. Similarly, IEEE 802.1Qbu and IEEE 802.3br introduce Frame Preemption to allow high-priority traffic to interrupt lower-priority transmissions and IEEE 802.1CB introduces Frame Replication and Elimination for Reliability (FRER).

Ziele der Seminararbeit:
• Give an overview over the aforementioned TSN standards and describe how they enable deterministic real-time communication.

Accurate clock synchronization is essential in networks requiring time-critical data transfer, where even minimal clock deviations can lead to significant operational errors. Given that the internal clocks of network devices inherently drift apart over time, clock synchronization is indispensable for reliable and error-free operations.

In wired Ethernet networks, the Generalized Precision Time Protocol (gPTP), standardized in IEEE 802.1AS, provides a widely adopted solution for precise time synchronization. gPTP extends the IEEE 1588 Precision Time Protocol (PTP) and is specifically tailored for bridged local area networks. It operates on a master-slave hierarchy, where one device assumes the role of Grand Master and distributes timing information to all other nodes. To achieve sub-microsecond accuracy, gPTP relies on hardware-based timestamping of packets, thereby minimizing the impact of software-induced delays. Furthermore, the protocol incorporates mechanisms to compensate for propagation delays across network links, ensuring that all devices share a consistent notion of time even in multi-hop topologies.

Ziele der Seminararbeit:
• Explain the mechanisms through which gPTP achieves precise time synchronization.
• Compare gPTP to other time synchronization protocols such as NTP.

Controlling access to memory plays a crucial role when building concurrent programs. Programmers often assume the operations of their programs to be executed sequentially and in-order. However, optimizations applied by the compiler, the CPU pipeline and the memory management unit can cause the operations of a program to be executed out-of-order. In multi-threaded applications, this has the potential to change the semantics of the program, resulting in unexpected observed behavior. Therefore, synchronization is necessary. The usage of memory barriers allows OS-level primitives (e.g., semaphores) or lock-free data structures to provide meaningful consistency guarantees.

Ziele der Seminararbeit:
• Investigate the usage and semantics of memory barriers in modern memory models such as the C++ memory model.
• Focus on the theoretical model behind acquire-release or sequentially consistent memory ordering as defined by the C++ standard.

This seminar topic focuses on the challenges of ensuring proper synchronization without relying on kernel-based synchronization. We will explore the concept of user-space mutex implementations, focusing particularly on spinlocks and their role in low-level synchronization within concurrent systems. We will analyze the mechanics of busy-wait locks, where threads continuously check the availability of a critical section, and the implications this has on processor utilization and cache coherence.

Ziele der Seminararbeit:
• Discuss spinlock implementations as synchronization primitives that avoid blocking and instead rely on active polling.
• Compare the test-and-set lock, the test-and-test-and-set lock, and MCS locks. Focus on the trade-offs in terms of efficiency under contention and multithreaded scalability.

When rapid deployment and flexibility are essential, decentralized architectures offer a significant advantage over traditional systems. Wireless Ad-Hoc Networks (WANETs) excel here by enabling independent nodes to spontaneously form networks. This is highly valuable for quickly establishing communication in remote, dynamic, or infrastructure-deprived environments.

While WANET concepts are well-established, real-world deployment on low-cost microcontrollers like the ESP32 introduces practical hurdles. Running standard routing protocols, such as Ad hoc On-Demand Distance Vector (AODV), efficiently on resource-constrained hardware can be challenging. Physical environments heavily impact network stability, especially when devices are sparsely distributed and fluctuating link quality dictates reliable route establishment.

Ziele der Seminararbeit:
• Introduce Wireless Ad-Hoc Networks (WANETs) and decentralized routing protocols.
• Explain the technical challenges of running protocols like AODV on low-cost microcontrollers.
• Analyze the impact of real-world physical constraints, focusing on how fluctuating link quality dictates route selection in sparse topologies.