Managing QoS for video delivery in shared-I/O environments

Compute farms also call for I/O QoS that can differentiate the various types of application/virtual machine flows within the infrastructure. In a shared I/O environment, the I/O devices are being shared across multiple processor complexes that require QoS built into I/O devices and converged fabrics. The converged fabric will need to carry the built-in QoS to I/O devices in the fabric to provide end-to-end application QoS.

QoS means different things to different people, and often is the source of confusion among designers, not the least of who develop video/imaging-systems. Let's look at QoS's role in consolidated/converged systems and the challenges designers face implementing it, and then examine straightforward methods for successful QoS deployment.

Video and IPTV systems
Today's converged infrastructures include voice, video and data traffic types. Video is a bandwidth-hungry application that requires higher speed and feed from servers, switches and other systems within the infrastructure. Video can be delivered with different protocols such as IPTV, surveillance camera and video on demand (VOD). Real-time applications such as these need QoS from both the network and infrastructure. QoS is supported in the data centers as well as in the telecom networks for end-to-end service- level agreements and support for real-time applications.

Figure 1 shows video ENDECs on a PCI Express (PCIe) subsystem. This card needs QoS implementation within the PCIe switch. The PCIe system provides policing and shaping functionality as part of the QoS implementation.

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Figure 1: Surveillance camera and video servers

Figure 1 illustrates how the video has been captured by the camera subsystem and RGB (red, green and blue components) is sent to the ENDEC, which digitizes the video signal and writes it to local CPU memory. This data is sent to graphics cards or to a network where it is being displayed at a common console. The PCIe switch plays a very important role here, providing QoS functionality while addressing the guaranteed bandwidth and latency to the video traffic.

Next: IPTV system, Shared-I/O system