20,284 research outputs found
Embedding of Virtual Network Requests over Static Wireless Multihop Networks
Network virtualization is a technology of running multiple heterogeneous
network architecture on a shared substrate network. One of the crucial
components in network virtualization is virtual network embedding, which
provides a way to allocate physical network resources (CPU and link bandwidth)
to virtual network requests. Despite significant research efforts on virtual
network embedding in wired and cellular networks, little attention has been
paid to that in wireless multi-hop networks, which is becoming more important
due to its rapid growth and the need to share these networks among different
business sectors and users. In this paper, we first study the root causes of
new challenges of virtual network embedding in wireless multi-hop networks, and
propose a new embedding algorithm that efficiently uses the resources of the
physical substrate network. We examine our algorithm's performance through
extensive simulations under various scenarios. Due to lack of competitive
algorithms, we compare the proposed algorithm to five other algorithms, mainly
borrowed from wired embedding or artificially made by us, partially with or
without the key algorithmic ideas to assess their impacts.Comment: 22 page
MARVELO: Wireless Virtual Network Embedding for Overlay Graphs with Loops
When deploying resource-intensive signal processing applications in wireless
sensor or mesh networks, distributing processing blocks over multiple nodes
becomes promising. Such distributed applications need to solve the placement
problem (which block to run on which node), the routing problem (which link
between blocks to map on which path between nodes), and the scheduling problem
(which transmission is active when). We investigate a variant where the
application graph may contain feedback loops and we exploit wireless networks?
inherent multicast advantage. Thus, we propose Multicast-Aware Routing for
Virtual network Embedding with Loops in Overlays (MARVELO) to find efficient
solutions for scheduling and routing under a detailed interference model. We
cast this as a mixed integer quadratically constrained optimisation problem and
provide an efficient heuristic. Simulations show that our approach handles
complex scenarios quickly.Comment: 6 page
Genetic Algorithm-based Mapper to Support Multiple Concurrent Users on Wireless Testbeds
Communication and networking research introduces new protocols and standards
with an increasing number of researchers relying on real experiments rather
than simulations to evaluate the performance of their new protocols. A number
of testbeds are currently available for this purpose and a growing number of
users are requesting access to those testbeds. This motivates the need for
better utilization of the testbeds by allowing concurrent experimentations. In
this work, we introduce a novel mapping algorithm that aims to maximize
wireless testbed utilization using frequency slicing of the spectrum resources.
The mapper employs genetic algorithm to find the best combination of requests
that can be served concurrently, after getting all possible mappings of each
request via an induced sub-graph isomorphism stage. The proposed mapper is
tested on grid testbeds and randomly generated topologies. The solution of our
mapper is compared to the optimal one, obtained through a brute-force search,
and was able to serve the same number of requests in 82.96% of testing
scenarios. Furthermore, we show the effect of the careful design of testbed
topology on enhancing the testbed utilization by applying our mapper on a
carefully positioned 8-nodes testbed. In addition, our proposed approach for
testbed slicing and requests mapping has shown an improved performance in terms
of total served requests, about five folds, compared to the simple allocation
policy with no slicing.Comment: IEEE Wireless Communications and Networking Conference (WCNC) 201
Impact of Processing-Resource Sharing on the Placement of Chained Virtual Network Functions
Network Function Virtualization (NFV) provides higher flexibility for network
operators and reduces the complexity in network service deployment. Using NFV,
Virtual Network Functions (VNF) can be located in various network nodes and
chained together in a Service Function Chain (SFC) to provide a specific
service. Consolidating multiple VNFs in a smaller number of locations would
allow decreasing capital expenditures. However, excessive consolidation of VNFs
might cause additional latency penalties due to processing-resource sharing,
and this is undesirable, as SFCs are bounded by service-specific latency
requirements. In this paper, we identify two different types of penalties
(referred as "costs") related to the processingresource sharing among multiple
VNFs: the context switching costs and the upscaling costs. Context switching
costs arise when multiple CPU processes (e.g., supporting different VNFs) share
the same CPU and thus repeated loading/saving of their context is required.
Upscaling costs are incurred by VNFs requiring multi-core implementations,
since they suffer a penalty due to the load-balancing needs among CPU cores.
These costs affect how the chained VNFs are placed in the network to meet the
performance requirement of the SFCs. We evaluate their impact while considering
SFCs with different bandwidth and latency requirements in a scenario of VNF
consolidation.Comment: Accepted for publication in IEEE Transactions on Cloud Computin
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