A Multi-Domain SDN Scalability Architecture implementation based on the
Coordinate Controller
Jianglong Wang, Guochu Shou, Yihong Hu, Zhigang Guo
Beijing Laboratory of Advanced Information Networks
School of Information and Communication Engineering
Beijing University of Posts and Telecommunications
Beijing 100876, China
{jianglong93, gcshou, yhhu, gzgang}@bupt.edu.cn
Abstract—Software-defined Networking, known as SDN, is a
novel architecture that decouples the control plane from the
data plane, and opens a programmable network. However, it is
common practice for network operators to divide the large-
scale networks into multiple domains and manage the
networks by using a group of controllers. Designing a scalable
SDN control plane becomes a critical problem. In this paper,
we propose a SDN scalability architecture for multi-domain,
multi-vendor networking. We design and implement the
Coordinator Controller to enable different SDN administrative
domains to cooperate by unifying the northbound APIs of the
controllers which are working for different SDN domains. To
validate the proposed architecture, we build a multi-domain
experiment environment consisting of three vendors. The
results show great ability in the network state view consistency
and end-to-end provisioning services.
Keywords-SDN scalability; Coordinate Controller; multi-
vendor; multi-domain;
I.
I
NTRODUCTION
With the development of the network services and web
applications, current network architecture which is
characterized by closed system does not favor network
innovation. Convergence, openness are the key features of
the future network [1]. SDN provides a programmable
network over abstracted network resources, by means of
separating the control plane from data plane and utilizing the
control plane in a centralized controller [2]. SDN is a well-
acknowledged technology supporting dynamic features of
future network and intelligent applications.
In the openflow-based SDN network, controller is used to
compute packet flow route path, generate flow tables, and
put them into the corresponding switches through openflow
protocol [3]. However, in the certain scale network, every
100 switches in the data center can produce 10000K request
per second [4], but NOX controller can only handle 30K
flow per second [5]. As the newly launched service flow
initial request is always sent to the controller, there must be a
serious problem about the response time of the new packet
flow [6]. Meanwhile, a single controller would be likely to
put the whole network at risk due to the single point of
failure [7]. Thus, as the number of SDN deployment
scenarios extends to the large scale networks, which consist
of multiple domains with different administrative vendors or
any other heterogeneous network, using multiple controllers
to manage the network becomes a common approach. The
concerns about SDN scalability are gradually introduced to a
multiple controller collaboration statement [8].
In this paper, we will have a comprehensive discussion
on the SDN scalability architecture and its latest progress.
Then, we will introduce a novel vendor-agnostic Coordinate
Controller to make SDN controllers work together. In order
to allow the Coordinate Controller to interact with SDN
controllers, we design the information should be exchanged
among domains and unify SDN domain controllers’
northbound APIs to share this information. More detailed
implementation plans are given, and we test this architecture
in multi-vendor SDN networking environment, and do the
northbound APIs (NBI) interoperability test, network state
view consistency test, end-to-end provisioning services test
over this vendor-agnostic Coordinate Controller.
II.
B
ACKGROUND AND RELATED WORK
A. Scalability Architecture
As it mentioned before, the SDN starts with a single
controller that would be responsible for the whole network,
such as NOX, POX. Although multi-core controller
demonstrates superior performance than traditional single
controller, it is still confronted with many barriers in its
function and performance limitation. A multi-controller
solution for control plane becomes necessary indeed [8].
Generally, SDN scalability architecture can be classified into
two types: horizontal and hierarchical structure.
Horizontal structure is that all of controllers should be in
the same level and communicate with each other in peer-to-
peer way through west-east interface. They have to share the
whole network information with each other to construct a
consistent state view. As the network topology changes, all
controllers will be synchronized its state with each other.
Thus, achieving consistence for each controller is under great
consideration, west-east interface plays an important role in
controller peers’ communication. To address this problem,
researchers propose West-East Bridge [9] for SDN networks
peering. The west-east interface can exchange the inter-
domain information among controllers and the West-East
Bridge should be compatible with different third-part
controllers and network view storage systems.
2016 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery
978-1-5090-5154-0/16 $31.00 © 2016 IEEE
DOI 10.1109/CyberC.2016.100
495
2016 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery
978-1-5090-5154-0/16 $31.00 © 2016 IEEE
DOI 10.1109/CyberC.2016.100
494
2016 International Conference on Cyber-Enabled Distributed Computing and Knowledge Discovery
978-1-5090-5154-0/16 $31.00 © 2016 IEEE
DOI 10.1109/CyberC.2016.100
494