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.

One of the primary application scenarios for mobile wireless multi-hop networks are disaster areas. However, these pose specific challenges for routing, such as mobility and highly unpredictable links. The main applications for disaster area networks - group-based voice communication and group-oriented, map-based tracking - can be realized using multicast groups. Thus, we decided to implement ODMRP for disaster area deployments. In several disaster area maneuver on-site deployments, we identified the need for extensions, making the protocol more suitable for real-world deployments. In this paper, we propose three extensions to ODMRP: (1) link quality based routing, (2) prioritization of control messages, and (3) overhead reduction mechanisms. In simulations as well as in real-world measurements, we show the benefit of the extensions proposed.

Nowadays, networked sensors are deployed in various scenarios. To transmit sensor data like GPS, temperature, or vital signs data robust communication networks are needed. Different applications and sensor types may have specific requirements to the transmission of their data regarding loss-tolerance, timeliness, priority, or completeness. These requirements are typically met by appropriate transport protocols. At the lower layers, heterogeneous networks like wireless mesh networks or long thin networks lead to specific channel characteristics that may require the use of specifically adapted transport protocols. Additionally, the type of scenario can also affect the transport layer, e.g., a scenario with static nodes compared to moving nodes with high mobility. Of course, there are many variable requirements of different sensor data streams and applications. But there are also some basic functionalities that are common, such as registering sensors at a receiver, timestamping of sensor data as well as synchronization of all nodes. Thus, we specify a new protocol for sensor data transmission and management (STMP) that provides the basic functionalities required by many sensor data streams while at the same time allowing a flexible choice of the transport protocol to be used.

Wireless multi-hop networks meet the requirements of disaster area scenarios by their definition. Recently, different mesh and Wireless Sensor Network (WSN) testbeds were deployed. However, these deployments do not meet the specific characteristics of disaster area scenarios. Developing algorithms and protocols for public safety scenarios and deploying public safety networks is a huge challenge.

Public safety organizations need robust communication networks to transmit different kind of sensor information. These networks must be reliable even when all infrastructure has been destroyed. Wireless multi-hop networks (such as Mobile Ad-Hoc Networks (MANETs), Wireless Sensor Networks (WSNs), and Wireless Mesh Networks (WMNs)) are supposed to meet the requirements of (1) spontaneous deployment, (2) being independent of any kind of existing infrastructure, and (3) robustness in the sense of self-organization and self-healing by their very definition. These networks have been a topic in research for more than a decade now. Recently, real-world tests and deployments provide valuable insights concerning challenges and future research directions. There are different mesh and WSN testbeds (e.g., [4, 9, 10]) enabling the research community to run tests in static real-world networks. However, concerning public safety requirements, there are significant differences: (1) No spontaneous deployment, (2) no or at least no mobility typical for public safety, (3) no typical applications and traffic for public safety scenarios. Due to these characteristics, developing algorithms and protocols for public safety scenarios and deploying public safety networks is a huge challenge.

In the recent years voice over IP (VoIP) telephony started to migrate from research to the market. In the future, all-IP networks will substitute the classical public switched telephone networks (PSTNs). Nowadays, there is no All-IP network yet, but many VoIP-providers already enable calls from VoIP to a PSTN and vice versa. By doing so, critical infrastructures within the PSTN like public safety answering points (PSAP), are accessible from the VoIP network (e.g. the Internet). Thus, there is a need for reliable performance modeling and evaluation. One aspect of particular interest e.g. for the performance evaluation of intrusion detection architectures for emergency call services is the characterization and modeling of emergency call length and frequency. In this paper, we provide a detailed analysis of traces from different PSAPs. Our work is based on empirical long-time measurements at two PSAPs. Based on these traces we characterize the load's interarrival times and call lengths concerning variation of the load, dependencies, and scalability. Furthermore, we provide fittings of the empirical data to standard probability distributions.

In the recent years Voice over IP (VoIP) telephony started to migrate from research to the market. In the future, All-IP networks will substitute the classical Public Switched Telephone Networks (PSTNs). Nowadays, there is no All-IP network yet, but many VoIP-providers already enable calls from VoIP to a PSTN and vice versa. Thus, critical infrastructures within the PSTN like the emergency call service, are accessible from the VoIP network (e.g. the Internet) and get exposed to new security threats. In particular, there is the risk of Denial of Service (DoS) attacks originating from the VoIP network. An attacker could jam the emergency call service by generating a massive load of faked emergency calls, which could lead to the loss of lives in the worst case. For us, this was the motivation to analyse the applicability of the concept of Intrusion Detection (ID) in the emergency call context and develop an adapted ID-architecture including its implementation. In an evaluation of the ID-architecture, using real emergency call traces from the fire department of Cologne, we show that the developed concept can reliably detect emerging DoS attacks from VoIP networks up to a certain VoIP diffusion rate.