Conference Paper

Keywords:
SDN controller · OpenFlow switch · Flow table · AnyLogic · Queue
model · Simulation model · Analytical model
1
Introduction
The concept of software defined networks (SDN) is a growing trend in the domain of
telecommunication network management, that offers to remove restrictions on existing
infrastructure networks by dividing the network control plane and data plane by means
of transferring control functions of network forwarding devices (routers, switches) in
the applications running on a single entity (controller), which makes the network more
centralized and improves its software management capabilities [
1
–
3
]. This simplifies
the network usability and significantly reduces the network system cost and equipment.
However, all these benefits come with a non-negligible problem in network functionality
such as packet transmission rate and network performance, which are attributed to the
use of the controller as a remote system to manage all transmission network devices
(switches). The controller can manage one or several OpenFlow switches; it contains a
network operating system that provides network services for low-level network
© IFIP International Federation for Information Processing 2017
Published by Springer International Publishing AG 2017. All Rights Reserved
Y. Koucheryavy et al. (Eds.): WWIC 2017, LNCS 10372, pp. 26–37, 2017.
DOI: 10.1007/978-3-319-61382-6_3

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management, network segments, and the state of network elements and applications,
implementing a high-level network management and data flow. Each controller has at
least one application that manipulates switches connected to it, and can provide a global
view of physical network topology under the controller management. The idea of
creating a unified, independent from the network equipment manufacturer [
4
–
6
],
program-controlled interface between the controller and the network transport infra‐
structure is defined in the OpenFlow standards and OpenFlow protocol [
7
], which allows
users to define and control with whom, under what conditions and with what quality can
interact on the network. OpenFlow is an open standard, which describes the remote
management requirements to a switch that supports OpenFlow protocol. According to
OpenFlow standard specifications, the interaction between the controller and the switch
is carried out through OpenFlow protocol. Each switch must contain one or more flow
tables and group tables, which perform packet lookups and forwarding, and support
OpenFlow secured channel to a remote controller. Each flow table in the switch contains
a set of flow entries; each flow entry consists of match fields, counters, and a set of
instructions to apply to matching packets. Data management in OpenFlow is carried out,
not on the individual packet level, but at the level of their packet streams. Rules are
dynamic. Packets which have no match are sent to the controller (packet in). Controller
creates appropriate rule and sends packet back to switch (packet out) for processing.
The rule in the switch is set only for the first packet, and then all the other packets of
the flow use it.
In this paper is introduced an analytical and simulation analysis of an SDN model
where the network is modelled as queueing system to capture the time costs associated
with the controller and the switches activities.