Monitoring is an important concept in network management as it helps network operators to determine the behavior of a network and the status of its components. Traffic engineering, quality of service, and anomaly detection also depend on monitoring for decision making. Software-defined networking (SDN) is becoming increasingly popular for network provision and management tasks. This paper surveys the tasks and challenges associated with SDN, providing an overview of SDN monitoring developments. Several design concepts, research directions, and open issues are also discussed.

The requirement of auto provisioning, administration, management and governing of networking resources in distributed environment, which spreads over multiple administrative domains (i.e., multi-domain) is a challenging task. This paper demonstrates an effort to inter-connect distributed SDN-Cloud resources which spread over three administrative domains in three different countries on OF@TEIN Playground. The proposed SD-Routing-Exchange utilizes BGP routing protocol as control-plane for federated multi-domain SDN-Cloud data-plane. This method has improved the flexibility of networking control, and provides reasonable interconnections redundancy and performance enhancement.

This paper shows a prototyping and operating effort for a federated multisite SDN-Cloud playground that leverages open-source software such as OpenStack cloud, ONOS SDN controller, and Quagga router. A SDN-based federation possibility for distributed multisite cloud is verified by providing an open playground over three international sites under separate administrative domains.

In global networks, Border Gateway Protocol (BGP) is widely used in exchanging routing information. While the original design of BGP did not focus on security protection against deliberate or accidental errors regarding to routing disruption, one of fundamental vulnerabilities in BGP is a lack of insurance in validating authority for announcing network layer reachability. Therefore, a distributed repository system known as Resource Public Key Infrastructure (RPKI) has been utilized to mitigate this issue. However, such a validation requires further deployment steps for Autonomous System (AS), and it might cause performance and compatibility problems in legacy network infrastructure. Nevertheless, with recent advancements in network innovation, some traditional networks are planning to be restructured with Software-Defined Networking (SDN) technology for gaining more benefits. By using SDN, Internet eXchange Point (IXP) is able to enhance its capability of management by applying softwarized control methods, acting as a Software-Defined eXchange (SDX) center to handle numerous advertisement adaptively. To use the SDN method to strengthen routing security of IXP, this paper proposed an alternative SDX development, SD-BROV, an SDX-based BGP Route Origin Validation mechanism that establishes a flexible route exchange scenario with RPKI validation. The validating application built in the SDN controller is capable of investigating received routing information. It aims to support hybrid SDN environments and help non-SDN BGP neighbors to get trusted routes and drop suspicious ones in transition. To verify proposed idea with emulated environment, the proof-of-concept development is deployed on an SDN testbed running over Research and Education Networks (RENs). During BGP hijacking experiment, the results show that developed SD-BROV is able to detect and stop legitimate traffic to be redirected by attacker, making approach to secure traffic forwarding on BGP routers.