We will review some of the major results in random graphs and some of the more challenging open problems. We will cover algorithmic and structural questions. We will touch on newer models, including those related to the WWW.

Random graphs

To support bursty traffic on the Internet (and especially WWW) efficiently, optical burst switching (OBS) is proposed as a way to streamline both protocols and hardware in building the future gener...

Optical burst switching (OBS) - a new paradigm for an optical Internet

As the rapid development of automotive telematics, modern vehicles are expected to be connected through heterogeneous radio access technologies and are able to exchange massive information with their surrounding environment. By significantly expanding the network scale and conducting both real time and long term information processing, the traditional Vehicular Ad- Hoc Networks U+0028 VANETs U+0029 are evolving to the Internet of Vehicles U+0028 IoV U+0029, which promises efficient and intelligent prospect for the future transportation system. On the other hand, vehicles are not only consuming but also generating a huge amount and enormous types of data, which are referred to as Big Data. In this article, we first investigate the relationship between IoV and big data in vehicular environment, mainly on how IoV supports the transmission, storage, computing of the big data, and in return how IoV benefits from big data in terms of IoV characterization, performance evaluation and big data assisted communication protocol design. We then investigate the application of IoV big data for autonomous vehicles. Finally the emerging issues of the big data enabled IoV are discussed.

Internet of vehicles in big data era

The new era of the Internet of Things is driving the evolution of conventional Vehicle Ad-hoc Networks into the Internet of Vehicles (IoV). With the rapid development of computation and communication technologies, IoV promises huge commercial interest and research value, thereby attracting a large number of companies and researchers. This paper proposes an abstract network model of the IoV, discusses the technologies required to create the IoV, presents different applications based on certain currently existing technologies, provides several open research challenges and describes essential future research in the area of IoV.

An overview of Internet of Vehicles

Cooperative adaptive cruise control (CACC) systems have the potential to increase traffic throughput by allowing smaller headway between vehicles and moving vehicles safely in a platoon at a harmonized speed. CACC systems have been attracting significant attention from both academia and industry since connectivity between vehicles will become mandatory for new vehicles in the USA in the near future. In this paper, we review three basic and important aspects of CACC systems: communications, driver characteristics, and controls to identify the most challenging issues for their real-world deployment. Different routing protocols that support the data communication requirements between vehicles in the CACC platoon are reviewed. Promising and suitable protocols are identified. Driver characteristics related issues, such as how to keep drivers engaged in driving tasks during CACC operations, are discussed. To achieve mass acceptance, the control design needs to depict real-world traffic variability such as communication effects, driver behavior, and traffic composition. Thus, this paper also discusses the issues that existing CACC control modules face when considering close to ideal driving conditions.

A Review of Communication, Driver Characteristics, and Controls Aspects of Cooperative Adaptive Cruise Control (CACC)

GeoSpray: A geographic routing protocol for vehicular delay-tolerant networks

Vehicular Delay-Tolerant Network (VDTN) is a new network architecture based on the concept of Delay Tolerant Networks (DTN). It aims to be an architecture that handles non-real time applications at low cost, under unreliable conditions, enabling connectivity in diverse scenarios, using vehicles to carry data between terminal nodes. For example, it can be applied in rural and remote areas, or in emergency scenarios. This paper proposes a layered architecture for VDTNs, using out-of-band signaling, based on the separation of the control plane and data plane. It presents the layers interactions and the envisioned protocols required at each layer. The paper provides a deep understanding of the characteristics of VDTN and reveal some design issues in its modeling, leading to insights for future theoretic study and protocol design.

/pdf/a-layered-architecture-for-vehicular-delay-tolerant-networks-upoub8knf2.pdf

A layered architecture for Vehicular Delay-Tolerant Networks

Compared to energy-awareness research in wireless and copper networks, less attention has been given to energy awareness in optical counterparts. In this paper, we introduce energy-aware traffic grooming problems for optical networks. We show that by looking further into the modular physical architecture of a node during request allocations, we can significantly reduce the number of active components and, hence, total energy consumption in the network, especially when traffic load is low. Since energy usage is an important element of operational expenditure (OPEX), this approach provides the financial motivation for service providers along with the desired environmental motivation. We present auxiliary graph based heuristics and justify our cases compared to traditional approaches with simulation results.

Traffic Grooming in Green Optical Networks

In this paper, we address the online multicast traffic grooming problem in wavelength-routed wavelength division multiplexing (WDM) mesh networks with sparse grooming capability. We develop a multicast dynamic light-tree grooming algorithm (MDTGA) that can support multihop traffic grooming by taking advantage of light-trees. In this algorithm, a light-tree can be dropped, branched, and extended when a route is to be established for a new request; a light-tree can also be contracted when some branches carry no effective traffic after requests depart from the network. The difficulty of the algorithm lies in the dynamic characteristic of light-trees. We implement MDTGA on a new auxiliary-graph model. For the purpose of comparison, we also implement a lightpath-based grooming algorithm by putting a constraint on the optical-splitting capability of the nodes. Through extensive simulations, we find that MDTGA has much better performance than the lightpath-based algorithm.

/pdf/multicast-traffic-grooming-in-wavelength-routed-wdm-mesh-1ay5u4nonc.pdf

Multicast traffic grooming in wavelength-routed WDM mesh networks using dynamically changing light-trees

Translucent networks utilize sparse placements of optical-electronic-optical (O/E/O) 3R (reamplification, reshaping, and retiming) regenerators to improve the cost effectiveness and energy efficiency of wavelength-routed optical transport networks. In this paper, we show that the energy cost of a translucent network can be further reduced by leveraging the energy efficiency of all-optical 2R (reamplification and reshaping) regenerators. We propose a translucent network infrastructure that uses all-optical 2R regenerators to partially replace O/E/O 3R regenerators and implements mixed regenerator placements (MRP). We first consider the problem of MRP along a single given path, and propose three path-based impairment-aware MRP algorithms, based on periodic placement, genetic algorithm (GA), and ant colony optimization (ACO). We then address the offline network planning problem and develop a heuristic algorithm. By incorporating with one of the proposed MRP algorithms, the heuristic can achieve joint optimization of MRP and routing and wavelength assignment for high energy efficiency. We design simulations to compare the performance of different offline network planning scenarios and to see which one can provide the best balance between quality of transmission and energy cost. Simulation results show that the algorithm achieves 58.91-73.62% saving on regeneration energy, compared to the traditional scheme without all-optical 2R regenerators. The results also indicate that the joint optimization using the MRP-GA obtains the best network planning in terms of energy efficiency. Finally, we address the problem of online provisioning, and propose several algorithms to serve dynamic lightpath requests in translucent networks with MRP, and implement them in simulations to compare their performance in terms of blocking probability. Simulation results indicate that the online provisioning algorithm that utilizes the combination of the MRP-GA and a multiple MRP scheme achieves the lowest blocking probability.

Farid Farahmand

Papers

GeoSpray: A geographic routing protocol for vehicular delay-tolerant networks

A layered architecture for Vehicular Delay-Tolerant Networks

Traffic Grooming in Green Optical Networks

Multicast traffic grooming in wavelength-routed WDM mesh networks using dynamically changing light-trees

Energy-Efficient Translucent Optical Transport Networks With Mixed Regenerator Placement