Robil Daher

Survey on Mobility and Multihoming in Future Internet

Mobility and multihoming represent key challenges for the development of the current and Future Internet, especially because of the rapid increase of user mobility and network heterogeneity. Both issues, mobility and multihoming, are closely related to each other and mainly issues of the used IP addressing scheme. This survey presents a general overview on approaches that enable mobility and multihoming in Future Internet; it focuses especially on approaches that suggest using new addressing schemes on layer 3, namely Locator/ID Separation and Core/Edge Separation, in order to tackle mobility and multihoming issues in an integrated manner. In our survey, we present a classification of the investigated approaches and summarize the main solution strategies. Furthermore, we evaluate the investigated approaches on basis of their capabilities and technical properties. On basis of the evaluation, where we emphasize the benefits and shortcomings of current solution strategies, we discuss future research issues related to mobility and multihoming.

QoS-Oriented Load Balancing for WLANs

The load balancing (LB) is essential for improving the WLAN efficiency, especially for VoIP over WLAN. Although 802.11v forms an important step to standardize LB in WLAN, nevertheless the concept, algorithms, and system model of LB are still required. In that respect, this paper proposes a novel concept for LB according to the graph representation of WLAN environment. In relation with WLAN features, a load distribution graph is constructed as the basis of the presented LB concept and algorithms in local scope. Accordingly, a QoS-oriented LB method and a system model are developed. Based on that, a system prototype, called Lobaq, is implemented according to the centralized architecture. The experimental results present the major functionalities of system behavior and provide an improvement of network balance in relation with the test scenario from lower than 37% to more than 73%. Moreover, these results confirm the LB according to the QoS requirements

Aspects of roadside backbone networks

The rapid deployment of wireless networks has radically changed the development methods of applications and solutions. Nevertheless, there are still poorly served areas with network infrastructures, especially the road systems when considering the intelligent transportation systems and on-the-road Internet and entertainment services. While the most known solutions of vehicular communications network concentrated on vehicle-to-vehicle and vehicle-to-roadside networks, road systems-oriented solutions for backbone infrastructures could not be found. Therefore, the demands on backbone infrastructure of roadside from perspective of applications as well as vehicles will be analyzed. Accordingly, a novel concept for a multi-layer wireless backbone based on 802.11 and 802.16 networks is proposed. The developed concept is adaptable for further access technologies.

Resource reservation and admission control in IEEE 802.11 WLANs

The Resource Reservation and Admission Control (RRAC) in WLAN networks is essential for real-time applications, especially VoIP over WLAN. In that respect, the RRAC mechanism must support the BSS and ESS scopes as well as different reservation types (per-flow, per-station, etc.). Therefore, we introduce the Traffic Source-based Priority Scheme (TSPS); TSPS enables the priority mapping with IntServ and IEEE 802.1D QoS schemes. To manage the WLAN resources according to the admission control, the channel capacity is mapped according to different types of traffic (management, applications, etc). Consequently, certain RRAC mechanisms and algorithms for BSS and ESS scopes are developed to deal with different architectures and reservation types. Based on that, we implement a system prototype, called Lobaq; the experimental results present the major functionalities of the system behavior under different conditions.

OPAL-VCN: Open-Air-Lab for vehicular Communication Networks

Vehicular Communication Networks (VCNs) provide a promising communication platform for Intelligent Transportation System (ITS) services as well as for value added services in different road systems. Despite the high demand on test fields for VCN related technical solutions and services, there are currently very few test fields for the immense requirement on test and R&D activities. Moreover, the known VCN-related test fields such as simTD and VII-California mainly focus on Vehicle-to-X communication (V2X), while there is less consideration of the requirements of related roadside backbone networks. This paper presents the Open-Air-Lab for VCNs (OPAL-VCN) as novel test field, especially concentrating on roadside backbone networks specified for VCN requirements. The OPAL-VCN is based on a wireless multi-layer roadside backbone network that employs modular and scalable system architecture. In this paper, we furthermore deal with the design, development and installation of OPAL-VCN. After completion, OPAL-VCN will comprise a test field of a total length of at least 30 km on the German highways A19 / A20 near Rostock city (Mecklenburg-Western Pomerania). Consequently, OPAL-VCN will provide an effective platform for R&D activities as well as for education and industry and can be used as basis for investigating and developing VCN related technologies and services.

Mobility-aware Forwarding mechanism for QoS enhancement in Wireless Mesh Backbones

Wireless Mesh Backbones (WMBs) provide promising solutions for future networking strategies. Due to the mesh nature and thus the resource restrictions of such backbones the integration of mobility aware preloading mechanisms is essential for QoS provisioning, especially in environments with high mobility clients. This paper presents a novel concept, called Mobility-aware Forwarding in Advance (MAFIA), to enhance the QoS provided by WMBs. Accordingly, two mechanisms are developed: best effort and QoS-oriented MAFIA. Best effort MAFIA mechanism provides preloading mechanism regardless of QoS requirements. QoS-oriented MAFIA considers traffic prioritization in conjunction with flows and their requirements. Both MAFIA mechanisms are used in a WMB developed as a roadside backbone network for vehicular environments.

Node-oriented Internet Protocol: A novel concept for enhancement of mobility and multi-homing in Future Internet

Mobility and multi-homing are closely related and mainly issues of the used IP addressing scheme. Novel addressing schemes that separate node identification and location are promising concepts to tackle the named issues. However, current approaches that make use of the address separation concept offer, among others, insufficient capabilities to select one or multiple network interfaces for a certain communication process, e.g. to enable load balancing. Therefore, we propose a novel approach called Node-oriented Internet Protocol (NIP). NIP adapts the address separation concept, introduces a novel three-tuple addressing scheme that adds an interface ID and enables network nodes to select sets of network interfaces to be used for communication sessions. Our work includes basic concepts for mapping system, schemes for packet forwarding, mechanisms for mobility and multi-homing support and strategies to ensure backwards compatibility. Building on that, the NIP concept enhances multi-homing and mobility capabilites with new functionalities in comparison to known approaches, especially referred to interface selection and bandwidth aggregation.

A Risk-Reward Competitive Analysis for Online Routing Algorithms in Delay Tolerant Networks

Delay Tolerant Networks (DTNs) suffer from frequent disruptions and partitioning. Because of dynamic environment and lack of knowledge about the whole network topology, routing is quiet challenging in DTNs. Prediction based algorithms in DTNs are able to predict nodes future contacts in the case where each node has a movement model. In this paper we suppose that a new node is added to the network which is about to send messages to a destination node and has no knowledge about the upcoming contacts. Deciding about the next node to forward the messages to, is an online problem. We are going to analyze a greedy forwarding strategy using competitive analysis and also propose a risk-reward analysis framework for the risky version of the algorithm and obtain risk and reward values for different forecasts. Risk-reward analysis can be used to develop better forwarding strategies which decide about the next hops more wisely.

Wireless Self-Organizing Backbone Mesh Network (WiSoNet)

Despite significant advances in parts of the physical layer, available WLAN systems still cannot offer wired equivalent bandwidth. In this paper we propose a novel concept, called wireless self-organizing backbone mesh network (WiSoNet), for a wireless network infrastructure as a backbone and describe its long-term potential. WiSoNet combines two major IEEE standards - IEEE 802.11 (WLAN) and IEEE 802.16 (WiMAX) to build a heterogeneous wireless network topology. To aggregate bandwidth of multiple WLAN connections we introduce a hybrid network solution that uses ad-hoc mechanisms. Further, to decrease the amount of administration and resource management, we use specific algorithms for the self-organization of routing and channels assignment. Since the WiMAX-based supply network already supports quality of service, we propose mechanisms to extend the QoS to end users. Accordingly, we present our prototypical system implementation and discuss the issues we will focus on in the future

A scalable mapping approach for locator-identifier-separation architectures with flat node ID space

Locator-Identifier-Separation (LIS) architectures introduce a novel addressing scheme by decoupling the node identification and locator functionalities into separate address parts in order to tackle mobility and multi-homing issues. As part of LIS concepts, a fast and global scalable mapping system is required to resolve the node ID into the corresponding locations. Current mapping systems are typically only applicable on hierarchical node ID spaces that violate the LIS principle, or they suffer from administrative and latency problems. In this paper, we propose a scalable multi-level mapping system that is applicable for flat node ID spaces. We apply hierarchical distributed hash tables (DHTs) and multiple cache levels to provide global scalability, a high grade of administrative autonomy and it reduces potential latency issues that can be caused by non-hierarchical DHTs. Within the scope of our work, we evaluate several hierarchical DHT technologies that can be used for that purpose and estimate the performance of our mapping approach.