2,681 research outputs found
Path computation in multi-layer networks: Complexity and algorithms
Carrier-grade networks comprise several layers where different protocols
coexist. Nowadays, most of these networks have different control planes to
manage routing on different layers, leading to a suboptimal use of the network
resources and additional operational costs. However, some routers are able to
encapsulate, decapsulate and convert protocols and act as a liaison between
these layers. A unified control plane would be useful to optimize the use of
the network resources and automate the routing configurations. Software-Defined
Networking (SDN) based architectures, such as OpenFlow, offer a chance to
design such a control plane. One of the most important problems to deal with in
this design is the path computation process. Classical path computation
algorithms cannot resolve the problem as they do not take into account
encapsulations and conversions of protocols. In this paper, we propose
algorithms to solve this problem and study several cases: Path computation
without bandwidth constraint, under bandwidth constraint and under other
Quality of Service constraints. We study the complexity and the scalability of
our algorithms and evaluate their performances on real topologies. The results
show that they outperform the previous ones proposed in the literature.Comment: IEEE INFOCOM 2016, Apr 2016, San Francisco, United States. To be
published in IEEE INFOCOM 2016, \<http://infocom2016.ieee-infocom.org/\&g
Path Selection for Quantum Repeater Networks
Quantum networks will support long-distance quantum key distribution (QKD)
and distributed quantum computation, and are an active area of both
experimental and theoretical research. Here, we present an analysis of
topologically complex networks of quantum repeaters composed of heterogeneous
links. Quantum networks have fundamental behavioral differences from classical
networks; the delicacy of quantum states makes a practical path selection
algorithm imperative, but classical notions of resource utilization are not
directly applicable, rendering known path selection mechanisms inadequate. To
adapt Dijkstra's algorithm for quantum repeater networks that generate
entangled Bell pairs, we quantify the key differences and define a link cost
metric, seconds per Bell pair of a particular fidelity, where a single Bell
pair is the resource consumed to perform one quantum teleportation. Simulations
that include both the physical interactions and the extensive classical
messaging confirm that Dijkstra's algorithm works well in a quantum context.
Simulating about three hundred heterogeneous paths, comparing our path cost and
the total work along the path gives a coefficient of determination of 0.88 or
better.Comment: 12 pages, 8 figure
Generic Dijkstra: correctness and tractability
The recently-proposed generic Dijkstra algorithm finds shortest paths in
networks with continuous and contiguous resources. The algorithm was proposed
in the context of optical networks, but is applicable to networks with finite
and discrete resources. The algorithm was published without a proof of
correctness, and with a minor shortcoming. We provide that missing proof and
offer a correction to the shortcoming. To prove the algorithm correct, we
generalize the Bellman's principle of optimality to algebraic structures with a
partial ordering. We also argue the stated problem is tractable by analyzing
the size of the search space in the worst-case
Is dynamic dedicated path protection tractable?
Intractable is the problem of finding two link-disjoint paths of minimal cost
if the path cost is limited since it can be a special case of the partition
problem. In optical networks, this limit can be introduced by the signal
modulation reach. Even without this limit, the existing literature suggested
the problem intractable because of the spectrum continuity and contiguity
constraints, but we show that the problem can be solved exactly with the
recently-proposed generic Dijkstra algorithm over a polynomially-bounded search
space, thus proving the problem tractable
Leveraging Semantic Web Technologies for Managing Resources in a Multi-Domain Infrastructure-as-a-Service Environment
This paper reports on experience with using semantically-enabled network
resource models to construct an operational multi-domain networked
infrastructure-as-a-service (NIaaS) testbed called ExoGENI, recently funded
through NSF's GENI project. A defining property of NIaaS is the deep
integration of network provisioning functions alongside the more common storage
and computation provisioning functions. Resource provider topologies and user
requests can be described using network resource models with common base
classes for fundamental cyber-resources (links, nodes, interfaces) specialized
via virtualization and adaptations between networking layers to specific
technologies.
This problem space gives rise to a number of application areas where semantic
web technologies become highly useful - common information models and resource
class hierarchies simplify resource descriptions from multiple providers,
pathfinding and topology embedding algorithms rely on query abstractions as
building blocks.
The paper describes how the semantic resource description models enable
ExoGENI to autonomously instantiate on-demand virtual topologies of virtual
machines provisioned from cloud providers and are linked by on-demand virtual
connections acquired from multiple autonomous network providers to serve a
variety of applications ranging from distributed system experiments to
high-performance computing
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