27,447 research outputs found
An Effective Approach to Controller Placement in Software Defined Wide Area Networks
This is the author accepted manuscript.
The final version is available from Institute of Electrical and Electronics Engineers via the DOI in this record.One grand challenge in Software Defined
Networking (SDN) is to select appropriate locations for
controllers to shorten the latency between controllers and
switches in wide area networks. In the literature, the
majority of approaches are focused on the reduction of
packet propagation latency, but propagation latency is
only one of the contributors of the overall latency between
controllers and their associated switches. In this paper, we
explore and investigate more possible contributors of the
latency, including the end-to-end latency and the queuing
latency of controllers. In order to decrease the end-to-end
latency, the concept of network partition is introduced and
a Clustering-based Network Partition Algorithm (CNPA)
is then proposed to partition the network. The CNPA can
guarantee that each partition is able to shorten the maximum
end-to-end latency between controllers and switches.
To further decrease the queuing latency of controllers,
appropriate multiple controllers are then placed in the
subnetworks. Extensive simulations are conducted under
two real network topologies from the Internet Topology
Zoo. The results verify that the proposed algorithm can
remarkably reduce the maximum latency between controllers
and their associated switches
The Role of Inter-Controller Traffic for Placement of Distributed SDN Controllers
We consider a distributed Software Defined Networking (SDN) architecture
adopting a cluster of multiple controllers to improve network performance and
reliability. Besides the Openflow control traffic exchanged between controllers
and switches, we focus on the control traffic exchanged among the controllers
in the cluster, needed to run coordination and consensus algorithms to keep the
controllers synchronized. We estimate the effect of the inter-controller
communications on the reaction time perceived by the switches depending on the
data-ownership model adopted in the cluster. The model is accurately validated
in an operational Software Defined WAN (SDWAN). We advocate a careful placement
of the controllers, that should take into account both the above kinds of
control traffic. We evaluate, for some real ISP network topologies, the delay
tradeoffs for the controllers placement problem and we propose a novel
evolutionary algorithm to find the corresponding Pareto frontier. Our work
provides novel quantitative tools to optimize the planning and the design of
the network supporting the control plane of SDN networks, especially when the
network is very large and in-band control plane is adopted. We also show that
for operational distributed controllers (e.g. OpenDaylight and ONOS), the
location of the controller which acts as a leader in the consensus algorithm
has a strong impact on the reactivity perceived by switches.Comment: 14 page
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