This demo paper presents a significant update on the software on ILDA Digital Network stream recording and playback which is based on the experience of previous work on the topic and aims at operating system independence and improved user friendliness. All major features and advances will be showcased at the LCN 2024 demo.

This demo paper presents an update on the IDNASIO-Driver (ILDA Digital Network) which is an Audio Stream Input/Output (ASIO) compliant driver, that can interface with ASIO based applications and can convert multi-channel sample data to IDN audio and laser data streams. The LCN 2022 demo focused on the playback part, the demo for LCN 2023 introduces the recording part with receiving IDN streams in different media formats. The demo will once again showcase the new elements in action and also will point out the interoperability to existing IDN elements.

This demo paper presents an update on ILDA (International Laser Display Association) audio stream specification in the context of the ILDA Digital Network (IDN). A framework of software elements is introduced to interface with audio hardware on a computer and other software that is able to handle multi-channel audio data. The demo will showcase the new elements in action and also will point out the interoperability to existing IDN elements.

Many MANET routing protocols do not perform well in dense scenarios with high network load. In these situations, we can observe a high level of route instability, which is often called "route flapping". In this paper we present the PRIME routing protocol, which uses a probabilistic multipath forwarding process to increase route stability in dense scenarios with high network load. We describe the routing protocol and propose different scenarios to evaluate the protocol performance. We compare the behavior of our protocol with the well-known OLSR and AODV protocols in those scenarios. The evaluation results show that the PRIME routing protocol does in fact have a positive impact on route stability and can improve the overall network performance in situations with high network load.

We investigate the conditions for streaming real-time laser data with commercial off-the-shelf hard- and software. We design scheduling algorithms to work around the identified limitations. We run end-to-end tests of our resulting software to show that we can achieve streams with millisecond granularity.

Welcome to this special issue of the Wiley's Wireless Communications and Mobile Computing Journal

This paper provides a model that realistically represents the movements in a disaster area scenario. The model is based on an analysis of tactical issues of civil protection. This analysis provides characteristics influencing network performance in public safety communication networks like heterogeneous area-based movement, obstacles, and joining/leaving of nodes. As these characteristics cannot be modelled with existing mobility models, we introduce a new disaster area mobility model. To examine the impact of our more realistic modelling, we compare it to existing ones (modelling the same scenario) using different pure movement and link based metrics. The new model shows specific characteristics like heterogeneous node density. Finally, the impact of the new model is evaluated in an exemplary simulative network performance analysis. The simulations show that the new model discloses new information and has a significant impact on performance analysis.

This paper deals with voice communication models for disaster area scenarios. The goal is to design models that can be used to generate realistic push to talk traffic for single talk groups. The modelling is based on an analysis of empirical measurements during a catastrophe maneuver. The analysis shows that the time series comprise heavy load periods and significant correlations. Based on these characteristics, different Markov and semi-Markov models are considered. Synthetic traffic streams for the different models are generated and evaluated by visual and statistical analysis. Finally, a case study outlines the impact of the different traffic models in network performance simulation

Disaster areas have been figured out as a typical usage scenario for mobile wireless ad-hoc networks (MANETs). In contrast to this, there are no specific mobility or traffic models for MANETs. We present a realistic approach to realize mobility in disaster areas based on tactical issues of civil protection. The new model is analyzed and compared to Gauss-Markov and random waypoint mobility models. Furthermore, we present first simulation results. The mobility model analysis as well as the simulation are based on two real disasters that occurred in Germany in 1999 and 2001. We show that disaster area scenarios have specific characteristics. Thus, they should be considered in MANET performance evaluation.

We examine the general influence of transmission power control on a wireless multi-hop network's throughput and compare topologies resulting from different transmission power control strategies. For this purpose, we introduce concepts for measuring certain characteristics of wireless multihop network topologies.

Differentiated services provide a scalable quality of service concept for the Internet. It allows differentiating service classes, which may be treated individually. The data arising between two neighboring network providers is regulated by service level agreements (SLA). The use of static SLAs lacks flexibility. With the introduction of bandwidth brokers a concept was provided enabling a dynamic differentiated services environment. Bandwidth brokers automatically negotiate and set up SLAs. However, this may still fail if there are bottlenecks in the network that may lead to congestion. This paper extends an existing scalable bandwidth broker concept for handling congestion in dynamic differentiated services networks. Our mechanism applies in contrast to any previous approach a dynamic overprovisioning and is able to handle different levels of congestion situations. With help of this dynamic overprovisioning we are able to maximize the utilization. The merits of this new concept are shown in simulation.

This paper presents a model for the expected throughput in a Bluetooth network in presence of a number of other Bluetooth networks that cause radio interference. The analysis considers unidirectional traffic and makes worst-case assumptions on the effect of radio interference. In order to verify the model, simulation results are presented. The results from this work may be very useful when designing ad-hoc networking functionality for future versions of Bluetooth.

This paper gives a survey on the impact of handover between heterogeneous links to the performance of TCP and elaborates on the effects TCP is challenged at the moment of a handover. Moreover, we propose several approaches to improve the performance of TCP in these situations and present an evaluation of these approaches by means of simulation.

The vision of ad-hoc networking with Bluetooth includes the concept of devices participating in multiple "piconets" and thereby forming a "scatternet". However, the details of scatternet support for Bluetooth are not specified yet. This paper presents a scheme for Bluetooth scatternet operation that adapts to varying traffic patterns. Being based on sniff mode, it does not require substantial modification of the current Bluetooth specification and may thus be incorporated into currently available Bluetooth products. We present simulation results that confirm the applicability of our approach to realistic scenarios.

We develop adaptive metrics to identify stable links in a mobile wireless networking environment based on the analysis of link durations in several different mobility scenarios. Our metrics only rely on online statistical evaluation of observed link durations. Neither do they require information on signal strength, radio conditions, or spacing of the mobile devices, nor do they depend on the availability of additional hardware such as GPS receivers or a synchronisation of the devices. We demonstrate the ability of the metrics to select stable links with a high probability in a wide range of scenarios.

The European Union funded projects DRIVE (Dynamic Radio for IP Services in Vehicular Environments) and OverDRiVE (Spectrum Efficient Uni- and Multicast Over Dynamic Radio Networks In Vehicular Environments) aim at enabling spectrum-efficient high-quality wireless IP communication in a heterogeneous multi-radio environment to deliver in-vehicle multimedia services. The IPv6 based network architecture for IP over multi-radio access networks and traffic control aspects has been developed in the DRiVE project. This paper presents relevant results of a performance analysis by simulation of the TCP handover behavior in the DRiVE multi-radio environment. Furthermore, the OverDRiVE project extends the scenario to mobile networks in larger vehicles like busses or trains, which imposes further interesting challenges on the IP-based network infrastructure and their protocols. The TCP handover evaluation will be continued in both the DRiVE and OverDRiVE scenarios.

Future applications of Bluetooth are likely to include ad-hoc networking. Therefore, it is desirable to interconnect multiple Bluetooth piconets to form a scatternet. Up to now, there is no extensive proposal for scatternet support available. We present and analyze an adaptive scheme for scatternet scheduling that is based on the sniff mode and thus does not require substantial modification of the current Bluetooth specification. The suitability of our approach is shown by first simulation results.

The European Union funded DRiVE project (dynamic radio for IP services in vehicular environments) aims at enabling spectrum-efficient high-quality wireless IP communication in a heterogeneous multi-radio environment to deliver in-vehicle multimedia services. The IPv6 based network architecture for IP over multi-radio access networks and traffic control aspects within the emerging DRiVE network plays a key role within the project. This paper gives an update of relevant changes of the DRiVE concepts compared to our previous report (see Lin Xu et al., Proc. LCN 2000, 25th Annual IEEE Conf. on Local Networks, 2000). It focuses on the system functions and network elements of the DRiVE IPv6 infrastructure and also considers the provision of quality of service.

The migration of the Internet from classic computer communication to a platform for multimedia applications with real-time communication requires end-to-end improvements of the network-level service. The proposal known as Differentiated Services is a very promising approach for implementing quality of service in the Internet and is being discussed and developed. The challenge is to deliver end-to-end QoS on top of Differentiated Services considering multiple concurrent application level data streams. We propose a QoS management system for multimedia servers that benefits from the scaling properties of layered media streams. This enables the system to map application QoS demands to available network resources and to adapt the quality of individual streams according to inter-stream QoS dependencies.

The BLUEPAC (BLUEtooth Public ACcess) concepts present ideas for enabling mobile Bluetooth devices to access local area networks in public areas, such as airports, train stations and supermarkets. The proposed protocols support mobility on OSI layer 3. This paper concentrates on the necessary layer 2 protocol concepts for supporting mobility and handoffs between different access points. Furthermore, we present the necessary adaptations for allowing IP datagrams to be exchanged between the mobile Bluetooth devices and access points. The BLUEPAC protocol concepts have been implemented above a Bluetooth emulation system to test their feasibility. First results clearly showed the importance of minimizing the handoff duration to allow efficient operation of upper layer protocols such as TCP.

The European Union funded DRiVE project (Dynamic Radio for IP Services in Vehicular Environments) aims at enabling spectrum-efficient high-quality wireless IP communication in a heterogeneous multi-radio environment to deliver in-vehicle multimedia services. Key issues are spectrum efficiency and dynamic spectrum allocation within different radio networks, the IPv6 based network infrastructure with inter-working of cellular and broadcast radio networks, as well as adaptive services for the vehicular environment with a high degree of mobility. The paper gives a general overview of the DRiVE project and focuses on the network architecture for IP over multi-radio access networks and traffic control aspects within the emerging "DRiVE" network.

We present protocol concepts for an extension of IP for mobility issues in Bluetooth networks. The protocol is called BLUEPAC IP, where BLUEPAC stands for "BLUEtooth Public ACcess". "Public access" means access to various kinds of information in public areas, e.g. airplane, train, hotel room, department store, museum. Bluetooth will reside in low-cost chips that provide wireless communication up to OSI Layer 2. By the end of this year many mobile devices, e.g. notebooks, PDAs, cell phones, will contain Bluetooth chips as a cable replacement. But Bluetooth is move powerful: with a suitable network protocol that inherits all aspects of IP, it will be possible to provide IP services over Bluetooth. BLUEPAC IP takes IP as a basis and additionally includes functionalities of mobile IP and cellular IP for local IP address assignment, routing issues and handoff support.

Previous articles by Frank and Martini (see 22nd Annual Conference on Local Computer Networks, LCN '97, Minneapolis, 1997 and 23rd Annual Conference on Local Computer Networks, LCN'98, Boston, 1998) on the concept of ROBIN (Regulation Of Bandwidth in Intra-Networks) gave a motivation for and presented first results of our approach to regulate the sending bandwidth of data flows in heterogeneous campus networks by determining bottlenecks and possible rate limitations with a global knowledge of the network state based on the end-to-end operation of the mechanism. This paper presents the latest results of our performance study of the ROBIN approach with a focus on the scalability and the concept of data flow aggregation within the bandwidth regulation. The QoS properties of ROBIN together with the flow aggregation for the local domain show a close relation to the ideas of the differentiated services activities for QoS support in the Internet, which is also discussed in this paper.

The variety and heterogeneity of different approaches for Quality of Service (QoS) support on different protocol layers result in the need of a solution with end-to-end overview and regulation of dataflows in a network. Previously we proposed the concept of ROBIN (regulation of bandwidth in intra-networks) to regulate the sending bandwidth of data flows in heterogeneous campus networks by determining bottlenecks and possible rate limitations with a global knowledge of the network state based on the end-to-end operation of the mechanism. This paper presents latest results of a simulation-based performance analysis studying the throughput fairness of an enhanced version of ROBIN and evaluating the impact of the bandwidth regulation on delays and packet losses in the network.

The inclusion of integrated quality of service (QoS) support in existing and future networking technologies and protocols has become a highly relevant area of research. But the variety and heterogeneity of different approaches for QoS support on different protocol layers result in the need of a solution with an end-to-end overview and regulation of data flows in a controllable subnetwork. The ROBIN (Regulation Of Bandwidth in Intra-Networks) concept introduced in this paper is such a mechanism which controls the bandwidth used by data flows in heterogeneous networks in case of network congestion. This paper presents an overview of the concept and reports on the state of simulative performance analysis work on ROBIN.

The paper presents an extension of the transport layer to control the bandwidth used by data flows in heterogeneous networks in case of network congestion. The regulation mechanism is operating on an end to end basis. It does not depend on a negotiation of quality of service (QoS) parameters prior to the data transmission. Instead it uses a relative QoS concept based on a classification of data flow requirements specified by the application. The paper describes the concept of the mechanism for Regulation Of Bandwidth in Intra-Networks (ROBIN) and presents first measurement results with a prototype implementation of ROBIN.

We study the impact of the selection of flow control functions in high-speed transport protocols on the performance for both nonbursty client-server traffic and bulk-data communication such as file transfer in a local high-speed environment. Therefore, we consider a workstation cluster based on a FDDI network. Although there are some differences in the behaviour all flow control and retransmission schemes studied (Go back N, Selective Repeat, Selective Retransmission) are able to provide the same performance in the local environment. Here an additionally used rate control scheme is able to reduce a high buffer utilization of a receiving station for a bulk-data transfer without any impact on the transfer delay and throughput. In the conclusion we discuss both functionality and implementational aspects of transport protocols.>