K. Tolga Bagci

Adaptive stereoscopic 3D video streaming

This paper presents a comparative analysis of scalable stereoscopic video coding strategies for adaptive streaming. In particular, we compare scalable simulcast coding of both views using SVC with scalable coding of one view with SVC and non-scalable coding of the other view using H.264/AVC, and benchmark them against non-scalable dependent coding of both views using the MVC. All of these coding options allow both symmetric and asymmetric coding of stereo videos. In addition, we propose a lightweight and periodic feedback mechanism for rate estimation and a strategy to adapt the total stereo source rate using SNR scalability option of SVC, while minimizing the loss rate of non-discardable packets. Experimental results show that dynamic rate scaling of only one view provides sufficient rate adaptation capability and better overall compression efficiency compared to scaling both of the views.

Queue-allocation optimization for adaptive video streaming over software defined networks with multiple service-levels

Internet service providers (ISP) are deploying software defined networking (SDN), which enables them to better utilize their resources and increase their revenues by offering on-demand differentiated services. In particular, SDN makes provisioning of dynamically managed video services with multiple levels of service viable, since the controller has complete vision of network resources and can change flow paths dynamically by continuously optimizing routes for each flow according to network state. This paper proposes a new method for flow-path computation by queue allocation with the objective of maximizing ISP revenues under per-flow service-level constraints. We formulate the optimization problem and implement its solution in the path computation unit of an SDN controller. Our experiments support that customers requesting improved quality video service receive significantly better QoE compared to best effort services to justify their paying extra for these services.

Scalable vs. multiple-description video coding for adaptive streaming over peer-to-peer networks

Both scalable video coding (SVC) and multiple description coding (MDC) have been evaluated in the literature for adaptive streaming over peer-to-peer (P2P) networks. However, these evaluations have used either unrealistic or too specific P2P topologies or omitted considering key video coding parameters such as compression efficiency and redundancy. In this study, we evaluate the performances of SVC, MDC and scalable multiple description coding (SMDC) with network-level adaptation schemes under varying peer bandwidth, average end-to-end delay, and peer exit ratio, as well as MDC redundancy levels. Extensive test results help us to reach conclusions regarding under which conditions SVC, MDC or SMDC should be preferred to achieve a reliable video service over mesh P2P overlays.

Dynamic end-to-end service-level negotiation over multi-domain software defined networks

We introduce a dynamic end-to-end (E2E) servicelevel management framework, which enables quality of experience to end users and efficient and flexible management of network resources for service providers, over a multi-domain SDN. In the proposed fully-distributed E2E service management framework, controllers of different domains negotiate with each other for the service level parameters of a specific service request. The main contribution of this paper is an automated dynamic E2E service-level negotiation procedure, where functions that manage E2E services can collaborate with functions that manage network resources of respective domains. The proposed framework and procedures have been verified over a large-scale multi-domain SDN emulation environment.

Managed video services over multi-domain software defined networks

We introduce a framework for provisioning end-to-end (E2E) managed video services over a multi-domain SDN, where different domains may be operated by different network providers. The proposed framework enables efficient dynamic management of network resources for network providers and ability to request the desired level of quality of experience (QoE) for end users. In the proposed fully-distributed E2E service framework, controllers of different domains negotiate with each other for the service level parameters of specific flows. The main contributions of this paper are a framework to provide E2E video services over multi-domain SDN, where functions that manage E2E services can collaborate with functions that manage network resources of respective domains, and a procedure for optimization of service parameters within each domain. The proposed framework and procedure have been verified over a newly developed large-scale multi-domain SDN emulation environment.

Virtualized cloud video services

We propose new architectures for collaborative video services using software defined networks (SDN) and cloud computing technologies. In the proposed architectures, the video service provider (VSP) is configured as a cloud service. The network service provider (NSP) employs SDN as a cloud service, consisting of a controller cloud and multiple edge network clouds. The proposed centralized and distributed collaborative cloud video services overcome quality of experience (QoE) fluctuations per flow and unfairness between multiple DASH clients employing TCP receive window adaptation over a network slice with reserved capacity as we show that quality of service (QoS) reservation alone is not sufficient to supply fair and steady QoE to all clients. In the centralized approach, the fair-share bitrate of each client is calculated by the traffic engineering module of the NSP, while in the distributed approach the clients collaborate with each other to calculate their own fair shares. Experimental results show that both collaboration architectures perform better than the competitive approach using standard TCP.

End-to-end service-level management framework over multi-domain software defined networks

We introduce a distributed, dynamic, end-to-end (E2E) service-level management framework over a multi-domain SDN in order to enable end users to negotiate with their service providers a level of service according to their needs and budget. In this framework, the service provider offers multiple levels of service and allocates network resources to each user to satisfy specific service level requests in a fair manner. To this effect, controllers of different domains negotiate with each other to satisfy the service level parameters of service requests, where functions that manage E2E services collaborate with functions that manage network resources of respective domains. The proposed framework and procedures have been verified over a newly developed large-scale multi-domain SDN emulation environment.

System architecture and emulator for multimedia streaming over multi-domain SDN

We propose a system architecture, an interface between controllers enabling them to exchange messages, and a Mininet-based emulation environment for video streaming over multi-domain software defined networks (SDN) with end-to-end quality of service. Emulation of large-scale multi-domain SDN with thousands of switches using the standard Mininet is impossible due to its performance limitations. In order to overcome this problem, cluster editions of Mininet have been proposed. Hence, our proposed emulation environment for video streaming over large-scale multi-domain SDN uses Mininet Cluster.