Hans-Peter Huth

M-MPLS: Micromobility-enabled multiprotocol label switching

This paper presents the integration of multiprotocol label switching with hierarchical mobile IPv6. The resulting micromobility-based MPLS (M-MPLS) is defined in two modes of operation: overlay and integrated. In an overlay framework MPLS and HMIP operate on their respective layers without having common processes, tables, or signaling. In an integrated framework, related functions are merged. The overall goal of an integrated framework is to facilitate efficient and reliable network operations while simultaneously optimizing network utilization and system performance.

Agile manufacturing: General challenges and an IoT@Work perspective

This paper describes the potential impact of the Internet of Things (IoT) technologies and architecture on factory automation. Whereas, IoT use cases range from intelligent infrastructure and smart cities to health care and shopping assistants, it is important to note that factory automation could benefit as well from an IoT approach. In this paper, we argue that there will not be one IoT but many IoTs that could differ in the type of infrastructure they are running or applications they support. In IoT@Work we focus on the potential of making manufacturing environments more agile and flexible. We explain how the IoT-centric architecture for manufacturing also needs a deep understanding of the manufacturing system and its state today. We, therefore, do a reverse engineering based on the requirements and the description of the agility expected in the automation system itself.

Securing layer 2 in local area networks

Network security problems have been well known and addressed in the application, transport, or network layers. However, the Data Link Layer (Layer 2) security has not been adequately addressed yet. To secure Local or Metropolitan Area Networks, the IEEE 802.1AE Media Access Control (MAC) Security Task Group has proposed the IEEE P802.1AE Standard for Local and Metropolitan Area Networks: MAC Security (MACsec). MACsec introduces a new tag field, Security TAG (SecTAG), in Layer 2 frames. In this paper, we discuss the security concerns in Layer 2 and summarize some of the possible attacks in Layer 2 in Internet Protocol (IP) over Ethernet networks. We also provide an overview of the MACsec. Lastly, we propose to incorporate additional fields into the SecTAG to improve security in local area networks.

Modeling mobility and workload for wireless metropolitan area networks

Research on large-scale wireless metropolitan area networks, which offer broadband capacity while supporting user and terminal mobility suffers from the lack of realistic mobility and workload models. There is a strong need for such models to be able to perform sound simulations supporting important yet difficult tasks like network planning and traffic engineering. In this paper, a novel approach towards realistic modeling of user mobility is proposed and studied. We formulate an analytical model, which is a hybrid of an empirical mobility model and a synthetic traffic model. The model clearly separates the influence of mobility and traffic to allow for greater flexibility. The mobility part is based on the combination of statistical zoning information with field data of movement patterns. This allows us to predict the density of users-classified into different groups-for a given area at a given time. We are able to integrate different traffic characteristics on top of our mobility model elegantly. The combination of user density with the predicted-synthetic-traffic of the modeled user groups gives the traffic and fluctuations of traffic throughout the network, thus describing the workload for the envisioned scenario. We present the instantiation of our model for the example of a real city. Analysis and simulations are provided which show that the proposed scheme is quite prospective. Our findings are, that our model is able to cover the macroscopic effects of real-world behavior more precisely than currently available mobility/workload models.

Comparative analysis of quality of service routing in wireless metropolitan area networks

Currently, we see the evolution of large scale community and metropolitan area networks based on inexpensive wireless local area network technology. We present the results of an experimental analysis, which investigates the potential of quality of service routing mechanisms within this challenging environment. Our investigation is based on a model of a radio access network designed to cover a large city center by means of decentralized and distributed routers, which are tightly meshed. The workload is modeled to reflect the estimated usage patterns based on statistical data collection of user mobility and combined with synthetic traffic matrices. We present results for various routing strategies including shortest path routing, delay constrained routing as well as various multipath quality of service routing variants. Moreover, we investigate different traffic distributions. Our findings are, that multipath routing is able to enhance the utility of the network significantly.

Online Traffic Engineering and Connection Admission Control Based on Path Queue States

In this paper, we outline a new connection admission control and online traffic engineering framework for small networks using differentiated services. Decisions are made at the edge routers of the network. Multiple label switched paths are set up between each pair of edge routers. When a new connection arrives at an edge router, each path is evaluated to see whether it is able to carry the connection. Then, the best path of the remaining ones is picked. The evaluation of paths is based on state information gathered from the queues on each path. We show the results this scheme achieves based on simulations.

A hybrid workload model for wireless metropolitan area networks

Wireless local and metropolitan area networks are en route to complement 2nd and 3rd generation cellular networks to provide for broadband wireless access for mobile users. The characterization and generation of realistic workload is important to allow for accurate network planning and traffic engineering. In this paper, we present the instantiation of a novel workload model, which is a hybrid of an empirical mobility model and a synthetic traffic model. We focus on the effects which are induced by user mobility. The model clearly separates the influence of mobility and traffic to allow for greater flexibility. Thus, we are able to integrate different traffic characteristics on top of our mobility model elegantly. We present results for the example of a real city and compare our model to existing synthetic models. Our findings are, that our model is able to cover the macroscopic effects of real world behavior more precise than currently available workload models.

Distributed bandwidth reservation by probing for available bandwidth

For many applications in Internet protocol-based networks a guaranteed quality of service is crucial. A simple and scalable way of achieving this is to use the differentiated services architecture in conjunction with admission control. In this research, we focus on the reservation of bandwidth by routers on the edge of a single network domain with differentiated services support. We evaluate the assumptions made by previous research on probe-based bandwidth reservation. The availability of bandwidth is determined by measuring the throughput a probe flow of a certain rate achieves while the reservation is accomplished by assuming that the throughput this probe flow achieves equals to an amount of reserved bandwidth.

Traffic engineering based on local states in Internet protocol-based radio access networks

The purpose of this research is to develop and evaluate a traffic engineering architecture that uses local state information. This architecture is applied to an Internet protocol radio access network (RAN) that uses multi-protocol label switching (MPLS) and differentiated services to support mobile hosts. We assume mobility support is provided by a protocol such as the hierarchical mobile Internet protocol. The traffic engineering architecture is router based — meaning that routers on the edges of the network make the decisions onto which paths to place admitted traffic. We propose an algorithm that supports the architecture and uses local network state in order to function. The goal of the architecture is to provide an inexpensive and fast method to reduce network congestion while increasing the quality of service (QoS) level when compared to traditional routing and traffic engineering techniques. We use a number of different mobility scenarios and a mix of different types of traffic to evaluate our architecture and algorithm. We use the network simulator ns-2 as the core of our simulation environment. Around this core we built a system of pre-simulation, during simulation, and post-processing software that enabled us to simulate our traffic engineering architecture with only very minimal changes to the core ns-2 software. Our simulation environment supports a number of different mobility scenarios and a mix of different types of traffic to evaluate our architecture and algorithm.

Probing available bandwidth in radio access networks

This paper presents a way of measuring whether a certain amount of bandwidth is available on a path in a radio access network or in other kinds of networks with DiffServ support. The basic concept is to fill up the bandwidth that is not used by normal data traffic with special probe packets, which are only forwarded if there are no data packets that could be forwarded. When probing multiple paths the interaction of different probe flows can be exploited to signal bandwidth requirements and to reserve bandwidth. In contrast to other approaches, the available bandwidth is not estimated by using statistical properties of the transmission of trains of packets but determined by measuring the actual throughput of a stream of low-priority probe packets.