Felix Espina

OBS network model for OMNeT++: a performance evaluation

Optical Burst Switching (OBS) is an optical switching technology capable of supporting large demands for bandwidth in optical backbones with Wavelength Division Multiplexing (WDM). This paper presents an OBS simulation model for the discrete event simulator OMNeT++. The performance of this model is compared with the performance of the well-known INET simulation model for IP networks. Both models show similar performance results. The OBS model is faster but uses more dynamic memory.

ETOMIC Advanced Network Monitoring System for Future Internet Experimentation

ETOMIC is a network traffic measurement platform with high precision GPS-synchronized monitoring nodes. The infrastructure is publicly available to the network research community, supporting advanced experimental techniques by providing high precision hardware equipments and a Central Management System. Researchers can deploy their own active measurement codes to perform experiments on the public Internet. Recently, the functionalities of the original system were significantly extended and new generation measurement nodes were deployed. The system now also includes well structured data repositories to archive and share raw and evaluated data. These features make ETOMIC as one of the experimental facilities that support the design, development and validation of novel experimental techniques for the future Internet. In this paper we focus on the improved capabilities of the management system, the recent extensions of the node architecture and the accompanying database solutions.

Analytical model for MPEG video frame loss rates and playback interruptions on packet networks

This paper presents and studies objective video quality evaluation techniques for a network where frame losses can be considered independent, for example a best effort not heavy loaded packet switching network. The total or partial loss of a frame’s information affects the quality of video playback, as the frame cannot be decoded and other frames that depend on it cannot be correctly decoded too. Therefore, during some time the video playback has errors in the image and the user will perceive them as interruptions. In this paper, the total number of decoded frames and the video playback interruptions duration will be considered important parameters to quantify the video quality. The analytical formulation for them will be presented and the importance of considering them together will be highlighted.

The effect of burst formation timers on video streaming over optical burst switched networks

Optical burst switching networks offer the capacity needed by bandwidth hungry services like video distribution to home subscribers. This paper shows the effect that the burst formation mechanism and its parameters has on video traffic flows. The dependence among video frames in MPEG flows shows a noticeable effect on the total number of frames that the video receiver cannot decode and the duration of the video playback interruptions. By tuning the parameters of the ingress node a quality of service objective can be achieved.

Improving Video Quality in Network Paths with Bursty Losses

This paper presents a method to improve video quality at the receiver side of a streaming service when the network path presents losses in bursts. Technologies that aggregate packets into larger switched data units are typical scenarios for this kind of loss behavior. Optical Burst Switched (OBS) networks and Optical Packet Switched (OPS) networks are examples of such technologies. Video quality is evaluated by means of a no reference video quality metric (the Frame Starvation Ratio). Results show that using video frame classification at the edge node and service differentiation at the network, the playback quality can be substantially improved.

Performance Analysis of OBS Edge Nodes for Video Streaming

OBS networks offer a highly efficient transport infrastructure for bursty data traffic. Video streaming content distribution networks are a clear candidate to use this promising technology. Traffic injected into an OBS network is a burst arrival process whose characteristics depend not only on input traffic parameters but also on design parameters of the OBS network. The properties of this traffic will dictate how it is affected by transmision over the OBS core and thus the user-perceived quality of the video stream that is delivered at the edge of the network. This paper evaluates different parameters in the ingress node that affect the losses suffered by the input traffic. Rules for the optimum selection of these parameters are presented: number of wavelengths, buffer size, timer value. The results show the strong dependence of losses on the timer value selected at the burst creation node.

On interconnecting and orchestrating components in disaggregated data centers: The dReDBox project vision

Computing systems servers -low- or high-end ones have been traditionally designed and built using a main-board and its hardware components as a “hard” monolithic building block; this formed the base unit on which the system hardware and software stack design build upon. This hard deployment and management border on compute, memory, network and storage resources is either fixed or quite limited in expandability during design time and in practice remains so throughout machine lifetime as subsystem upgrades are seldomely employed. The impact of this rigidity has well known ramifications in terms of lower system resource utilization, costly upgrade cycles and degraded energy proportionality. In the dReDBox project we take on the challenge of breaking the server boundaries through materialization of the concept of disaggregation. The basic idea of the dReDBox architecture is to use a core of high-speed, low-latency opto-electronic fabric that will bring physically distant components more closely in terms of latency and bandwidth. We envision a powerful software-defined control plane that will match the flexibility of the system to the resource needs of the applications (or VMs) running in the system. Together the hardware, interconnect, and software architectures will enable the creation of a modular, vertically-integrated system that will form a datacenter-in-a-box.

Effective edge node configuration for video transport over Optical Burst Switched networks

Abstract This paper considers digital video transport over Optical Burst Switched networks where burst losses cause data loss from one or more adjacent video frames. Analytical approximations for the frame losses and video playback interruptions are derived and validated using simulations. Both parameters require a very limited and static amount of data about the video on the user side and some quality of service metrics about the network to quantify the quality of the received video. The results take into account the strong dependency in the video traffic structure due to the coding mechanisms. The critical effect of video coding parameters is also revealed. The paper also presents a Traffic Engineering procedure to select the best parameters for the edge node and the video codec to meet a given video quality level on the user side.