217 research outputs found
Unidirectional Quorum-based Cycle Planning for Efficient Resource Utilization and Fault-Tolerance
In this paper, we propose a greedy cycle direction heuristic to improve the
generalized redundancy quorum cycle technique. When applied using
only single cycles rather than the standard paired cycles, the generalized
redundancy technique has been shown to almost halve the necessary
light-trail resources in the network. Our greedy heuristic improves this
cycle-based routing technique's fault-tolerance and dependability.
For efficiency and distributed control, it is common in distributed systems
and algorithms to group nodes into intersecting sets referred to as quorum
sets. Optimal communication quorum sets forming optical cycles based on
light-trails have been shown to flexibly and efficiently route both
point-to-point and multipoint-to-multipoint traffic requests. Commonly cycle
routing techniques will use pairs of cycles to achieve both routing and
fault-tolerance, which uses substantial resources and creates the potential for
underutilization. Instead, we use a single cycle and intentionally utilize
redundancy within the quorum cycles such that every point-to-point
communication pairs occur in at least cycles. Without the paired
cycles the direction of the quorum cycles becomes critical to the fault
tolerance performance. For this we developed a greedy cycle direction heuristic
and our single fault network simulations show a reduction of missing pairs by
greater than 30%, which translates to significant improvements in fault
coverage.Comment: Computer Communication and Networks (ICCCN), 2016 25th International
Conference on. arXiv admin note: substantial text overlap with
arXiv:1608.05172, arXiv:1608.05168, arXiv:1608.0517
Resource efficient redundancy using quorum-based cycle routing in optical networks
In this paper we propose a cycle redundancy technique that provides optical
networks almost fault-tolerant point-to-point and multipoint-to-multipoint
communications. The technique more importantly is shown to approximately halve
the necessary light-trail resources in the network while maintaining the
fault-tolerance and dependability expected from cycle-based routing. For
efficiency and distributed control, it is common in distributed systems and
algorithms to group nodes into intersecting sets referred to as quorum sets.
Optimal communication quorum sets forming optical cycles based on light-trails
have been shown to flexibly and efficiently route both point-to-point and
multipoint-to-multipoint traffic requests. Commonly cycle routing techniques
will use pairs of cycles to achieve both routing and fault-tolerance, which
uses substantial resources and creates the potential for underutilization.
Instead, we intentionally utilize redundancy within the quorum cycles for
fault-tolerance such that almost every point-to-point communication occurs in
more than one cycle. The result is a set of cycles with 96.60% - 99.37% fault
coverage, while using 42.9% - 47.18% fewer resources.Comment: 17th International Conference on Transparent Optical Networks
(ICTON), 5-9 July 2015. arXiv admin note: substantial text overlap with
arXiv:1608.05172, arXiv:1608.0516
Resource Allocation in Survivable WDM Networks Under a Sliding Scheduled Traffic Model
In recent years there has been an increasing number of applications that require periodic use of lightpaths at predefined time intervals, such as database backup and on-line classes. A new traffic model, referred to as the scheduled traffic model, has been proposed to handle such scheduled lightpath demands. In this thesis we present two new integer linear program ( ILP) formulations for the more general sliding scheduled traffic model, where the setup and teardown times may vary within a specified range. We consider both wavelength convertible networks and networks without wavelength conversion capability. Our ILP formulations jointly optimize the problem of scheduling the demands ( in time) and allocating resources for the scheduled lightpaths. Simulation results show that our formulations are able to generate optimal solutions for practical sized networks. For larger networks, we have proposed a fast two-step heuristic to solve the demand scheduling problem and the RWA problem separately
Light-Hierarchy: The Optimal Structure for Multicast Routing in WDM Mesh Networks
Based on the false assumption that multicast incapable (MI) nodes could not
be traversed twice on the same wavelength, the light-tree structure was always
thought to be optimal for multicast routing in sparse splitting Wavelength
Division Multiplexing (WDM) networks. In fact, for establishing a multicast
session, an MI node could be crosswise visited more than once to switch a light
signal towards several destinations with only one wavelength through different
input and output pairs. This is called Cross Pair Switching (CPS). Thus, a new
multicast routing structure light-hierarchy is proposed for all-optical
multicast routing, which permits the cycles introduced by the CPS capability of
MI nodes. We proved that the optimal structure for minimizing the cost of
multicast routing is a set of light-hierarchies rather than the light-trees in
sparse splitting WDM networks. Integer linear programming (ILP) formulations
are developed to search the optimal light-hierarchies. Numerical results
verified that the light-hierarchy structure could save more cost than the
light-tree structure
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