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In this paper we introduce the concept of differential capacity p-cycles as an enhancement to span protecting p-cycles. DC cycles provide increased capacity efficiency by reducing the amount of spare capacity that needs to be reserved on each link of a cycle. Our results show a small reduction in spare capacity requirement over traditional p-cycles. We also present a joint spare and working capacity...
Recent work has revealed a new, relatively simple and possibly cost-effective, approach to achieve combined protection of optical networks against both node and span failures. The resulting network designs use only a single set of p-cycle structures that have the same or only slightly more capacity than a corresponding optimal set of p-cycles for span protection. The new principle is based on a generalization...
Most of the present optical interconnect networks within the high performance computers require either the buffering and opto-electonic conversion of the data packets or the pre-assigning of the optical path from the source to destination, which to a certain extent influence the performance metrics such as latency and throughput. Aiming at the limitation mentioned above, a hybrid optical-electrical...
We consider the offline version of the routing and wavelength assignment (RWA) problem in transparent all-optical networks. In such networks and in the absence of regenerators, the signal quality of transmission degrades due to physical layer impairments. We initially present an algorithm for solving the static RWA problem based on an LP relaxation formulation that tends to yield integer solutions...
Optical packet switching (OPS) technologies are among the most promising solutions for next generation network architectures. Resource contention resolution and Quality of Service (QoS) management mechanisms have been developed in order to remedy the lack of optical buffering and implement multi-service support in OPS networks. In this paper we propose an analytical model for the access and core nodes...
With the extremely high volume of traffic carried on wavelength division multiplexing (WDM) networks, survivability becomes increasingly critical in managing high speed networks. In a WDM network, the failure of network element (i.e. fiber links, and cross connects) may cause the failure of several optical channels, thereby leading to large data loss. Here the different approaches are investigated...
Routing in multilayer optical networks can be made efficient if label switched paths are searched in a wavelength graph that represents the state and the switching facilities of the network devices very accurately. Maintaining the wavelength graph by using the conventional link state advertisement control mechanism leads to scalability problem. Much of the link state information is, however, redundant...
Burst contention is a well-known challenging problem in optical burst switching (OBS) networks. Deflection routing is used to resolve contention. Burst retransmission is used to reduce the burst loss ratio (BLR) by retransmitting dropped bursts. Previous works show that combining deflection and retransmission outperforms both pure deflection and pure retransmission approaches. This paper proposes...
We present a MIP formulation and an efficient heuristic for the problem of logical topology design for a distributed computing application to survive one computing cluster failure and one fiber link failure in WDM networks.
This paper puts forward a new method of channel monitoring for the optic fiber longitudinal differential protection. It involves following approaches: the differential protections at two ends of line communicate according to designed message frame format; calculate and store the communication channel delay of each message frame; estimate the stability of channel delay according to the criterion inequality,...
To guarantee a high switching speed, routing in vertically stacked optical banyan (VSOB) networks needs special attention so that connections are established as fast as possible. Previously proposed Pruned Vertically Stacked Optical banyan (P-VSOB) networks used Plane Fixed Routing (PFR) algorithm, and has O(log2N) time complexity. Blocking probability has also been analyzed for these kinds of networks...
In this paper, we investigated designing multicast-capable optical cross-connects (MC-OXCs) on a basis of the 4- stage multicast network. Firstly, we derive the sufficient wide- sense nonblocking (WSNB) and rearrangeable nonblocking (RNB) conditions for the 4-stage multicast network with only two (the second and output) stages being multicast-capable. Both WSNB and RNB 4-stage multicast networks need...
Optical burst switching (OBS) networks can benefit from optical buffering at the core nodes. Unfortunately, optical fibre delay line (FDL) buffers require additional switch ports, thereby increasing the switch size and cost. In this paper, an alternative and relatively uncommon view is taken towards core buffering in optical networks. Switch channel ports at underutilized links are replaced by buffer...
We present a hierarchical algorithm for grooming lightpaths into wavebands, and routing wavebands over a network of multigranular switching nodes. This algorithm focuses on lowering the number of wavelengths W and ports over the network while being conceptually simple, scalable, and consistent with the way networks are operated and controlled in practice. Our experiments indicate that this algorithm...
The Data Vortex switch architecture has been proposed as a scalable low-latency all-optical path interconnection fabric for packet switches. To facilitate optical implementation, the Data Vortex architecture employs a cylinder hierarchical topology, synchronous timing and deflection routing that act to reduce the necessary routing logic operations and buffering. The angle parameter of the Data Vortex...
The GMPLS/OBS Control Plane is a bold research topic. Optical Burst Switching (OBS) networks need to be capable to be rapidly reconfigured with the aim of achieving an efficient use of bandwidth, low latency and high degree of transparency. The OBS Control Plane is just a packet switched network requiring a high control complexity. The demands are clear but a well-defined control plane is still an...
Carrier networks are gradually adopting a network model that consists of MPLS-capable routers and OXCs interconnected by high bandwidth WDM links for transporting IP and Ethernet traffic. A control plane can be used to deliver dynamic circuit provisioning in the transport layer, as well as bandwidth provisioning and traffic engineering in higher layers. Globalization drives the quest for end-to-end...
We demonstrate routing of 8-WDM-channel 10 Gb/s optical packets through an 8-node sub-network of the data vortex, realizing virtual buffering within the switching fabric. Single pulse WDM encoding for the header simplifies packet control and reduces latency.
We demonstrate the impact of optical switch, amplifier and MUX/DEMUX characteristics on optical network performance evaluated from our physical-impairment-based RWA algorithm. We present blocking probabilities as a function of traffic load and network device parameters.
This paper proposes dynamic optical-path generation algorithms and evaluates the impact of these on the performance of the IP+Photonic multi-layered GMPLS network comprising label-switching routers with integrated packet and lambda switching capability. The optical label-switched path (O-LSP) Creation first (OCF) strategy provides excellent throughput in the case of high network capacity
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