Abstract-This paper provides an introductory overview of Vehicular Delay-Tolerant Networks. First, an introduction to Delay-Tolerant Networks and Vehicular Delay-Tolerant Networks is given. Delay-Tolerant schemes and protocols can help in situations where network connectivity is sparse or with large variations in density, or even when there is no end-to-end connectivity by providing a communications solution for non realtime applications. Some special issues like routing are addressed in the paper and an introductory description of applications and the most important projects is given. Finally, some research challenges are discussed and conclusions are detailed.

Abstract-Future optical communication networks are expected to change radically during the next decade. To meet the demanded bandwidth requirements, more dynamism, scalability and automatism will need to be provided. This will also require addressing issues such as the design of highly distributed control plane systems and their associated algorithms to respond to network changes very rapidly. In this work, we propose the use of an ant colony optimization (ACO) algorithm to solve the intrinsic problem of the routing and wavelength assignment (RWA) on wavelength continuity constraint optical networks. The main advantage of the protocol is its distributed nature, which provides higher survivability to network failures or traffic congestion. The protocol has been applied to a specific type of future optical network based on the optical switching of bursts. It has been evaluated through extensive simulations with very promising results, particularly on highly congested scenarios where the load balancing capabilities of the protocol become especially efficient. Results on a partially meshed network like NSFNET show that the ant-based protocol outperforms other RWA algorithms under test in terms of blocking probability without worsening other metrics such as mean route length.

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This paper presents the TSON metro mesh network architecture for guaranteed, statistically-multiplexed services. It proposes tunable time-wavelength assignment, one-way treebased reservation and node architecture. Results demonstrate high network efficiency, fast service delivery and guaranteed QoS. IntroductionA broad range of emerging services and applications (wide-range of multi-media, distributed applications such as Cloud, etc.) are driving the growing trend of network traffic with increasing demand for high bandwidth and flexibility. In addition, such applications require guaranteed multi-granular short-lived services i.e., from seconds to minutes with bandwidths from sub-wavelength to multi-wavelength. In order to provide these services, a new architecture is required that can support multiple end-to-end lightpaths (LPs) over single (or multiple) wavelength(s) and deliver dynamic access to transparent multi-granular flows as a guaranteed (no contention) network service.Optical packet switching (OPS) and optical burst switching (OBS) have been proposed to support subwavelength services [1]. However, these techniques do not provide guaranteed bandwidth services. Recently, TimeDriven-Switched Optical Network [2] has proposed to deliver sub-wavelength switched synchronous virtual pipes. To guarantee such services, this approach uses a synchronous global common time reference from Galileo or GPS. Also, LOBS-H [3] is an alternative solution that allocates wavelength sharable home circuits for each sourcedestination pair. These circuits provide guaranteed bandwidth for conforming traffic that originates from the same source to different destinations and also allow for non-guaranteed statistically multiplexed non-conforming traffic from any source to any destination. Furthermore, there has been considerable effort on routing, wavelength and time assignment (RWTA) algorithms to calculate two-way reserved Time Division Multiplexed (TDM) wavelength services [4]. It is also worth noting that current approaches consider ring solutions [1,5] for metro. This introduces additional complexity on how to interconnect all nodes (e.g. interconnected rings) and deliver the bandwidth services over topologies such as the one portrayed in Fig. 1.a that have an inherit mesh multi-degree connectivity.In this paper, a novel optical network solution is proposed -the Time Shared Optical Network (TSON) -to deliver both highly flexible statistically multiplexed optical network infrastructure and on-demand guaranteed contention-free time-shared multi-granular services. It supports traffic flows from any source to any destination in transparent optical networks for the metro region supporting the physical interconnection requirements. The architecture is based on user/application-driven bandwidth service requests, centralized RWTA calculation, and oneway tree-based provisioning that allows for flexible symmetric/asymmetric multi-granular bandwidth services with the use of either fixed or tunable transceivers. It delivers conte...

Current scientific data applications require advanced network provisioning systems to support the transport of large volumes of data. Due to the availability of diverse\ud computing and Grid clusters, these applications can benefit from anycasting capabilities. In contrast to unicasting, anycast routing allows the selection of a node from a group of candidate destinations. This new means of communication allows for greater routing flexibility and better network resource consumption.\ud However, current provisioning systems do not provide fully compliant anycast implementations. In this paper, we extend\ud ESnet’s OSCARS virtual circuit provisioning system with anycast routing capabilities to support destination-agnostic applications\ud on single- and multi-domain network scenarios. The proposed implementation significantly improves provisioning success over the native unicast implementation in compliance with the existing OSCARS framework.Peer ReviewedPostprint (author’s final draft