Conference Paper

2
SDN Modelling Concept
In case of SDN deployment, the controller usually manages multiple OpenFlow switches
each connecting group of host. The typical SDN architecture is shown in Fig. 
1
. The
OpenFlow switch packet forwarding procedure is shown in Fig. 
2
. The switch performs
flow table lookups on packet arrivals. If the lookups succeed, the switch applies the
actions in the matched table entry to the packet, typically forwarding it to the specified
interface. Otherwise, the packet is supposed to belong to a new flow, and the switch
sends it to the upper SDN controller in a packet-in message. The controller defines the
corresponding flow rules and sends to the switch it in packet-out or flow_mod packet.
As a result, the SDN controller receives a flow of packet-in messages from each Open‐
Flow switch.
In the modern telecommunication networks, at the same time are processed different
types of information (video and audio information, compressed video and audio infor‐
mation, and less sensitive to delay data) with different quality of service levels. Accord‐
ingly, traffic management methods play a key role in its optimization and to minimize
network losses. To create a network model (topology and its elements characteristics),
and dynamically simulate its operation mechanism, optimize its characteristics, analyze
and manage the traffic, evaluate the performance bounds undoubtedly, it is more than
Analysis and Performance Evaluation of SDN Queue Model
27

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necessary to use more advanced multimethod modeling and simulation tools for
complex systems research [
8
–
10
].
Fig. 1.
A typical SDN architecture.
Fig. 2.
The packet forwarding of an OpenFlow switch.
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Model Description
Operations on SDN switches with different data transmission processes control capa‐
bilities lead to a significant delay change for flow entries configuration. In order to
simulate different general arrival processes, describe and monitor flow exchange
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S. Muhizi et al.

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between the controller and the switches we presented the SDN as queuing system. The
SDN queue model was built using AnyLogic Multimethod simulation modeling tool
and is shown in Fig. 
3
. AnyLogic is a very flexible [
11
], dynamic simulation tool with
high flexibility and unlimited expansion possibilities due to operating system-inde‐
pendant native Java environment. AnyLogic runs on Windows, Mac and Linux.
AnyLogic initially designed to support multiple modeling methods and their arbitrary
combinations it offers the modeler more flexibility than any other existing simulation
tools by the means of reduction of development costs and -times: fast integration of pre-
configured simulation elements with the comprehensive object libraries. It makes it
possible to design various types of models with one single tool: agent-based, system
dynamic, event-oriented, continuous or dynamic models.
Fig. 3.
SDN conceptual model in AnyLogic 7.3.6
The SDN model consists of 6 OpenFlow switches and a controller. Switches are
numbered from S0 to S5 and the controller C0. Source objects generate incoming traffic
with a specified arrival rate at each and every switch connected to controller.