Frequency-flexible clock generators for Cloud apps -

Frequency-flexible clock generators for Cloud apps


Skyrocketing network bandwidth demands driven by consumer mobile devices and cloud-based streaming services, such as Netflix, Hulu, YouTube, Spotify, Pandora, online gaming and others, are pushing Internet Infrastructure suppliers to develop data center systems that support dramatically higher data rates, such as 10G, 40G and 100 Gbps.

In addition, the increasing popularity of commercial cloud computing, which offers network-based computing and storage as a service, is further accelerating the demand for application-flexible, high-bandwidth networks in today’s data centers.

Figure 1 illustrates the impact of these popular cloud-based streaming services on the growth of Internet traffic bandwidth. Cisco’s Visual Networking Index (VNI) Forecast (June 2014) projects the following market trends:  

  • Cloud applications and services such as Netflix, YouTube, Pandora, and Spotify, will account for 90 percent of total mobile data traffic by 2018.
  • Global network traffic will be three times larger in 2018 than in 2013, equivalent to streaming 33B DVDs/month, or 46M DVDs/hour.
  • By 2018, consumer online gaming traffic will be four times higher than it was in 2013.



Figure 1. Cisco VNI June 2014


Cloud-Based Apps Drive Network Convergence in the Data Center

To reliably deliver a Netflix video or a Spotify high-quality audio stream, service providers must be equipped with data center hardware that supports three primary networks, as shown in Figure 2 :  

  • LAN/WAN networks commonly comprise 1 Gb, 10 Gb, and/or 100 Gb Ethernet switches connected in a mesh switch fabric for the data center LAN, and OTN (Optical Transport Networking) interconnects to the WAN. These networks deliver the content from the data center to the cloud and, ultimately, to the user.


  • Compute networks comprise many server and switch “blades” interconnected using copper cables, PCB backplanes or optical links. These interconnects use a combination of 1 Gb, 10 Gb Ethernet, PCIe, and in some cases, InfiniBand. Network interfaces in compute networks must support not only high data rates but also very low latency, which is critical for streaming video and audio service quality.


  • Storage networks are primarily based on Fiber Channel, Gb or 10Gb Ethernet switches and direct connections to storage subsystems using PCIe. These networks store considerable amounts of content, requiring multi-gigabit capable protocols.

Figure 2. Data Center Network Overview


To meet the rapidly expanding Internet bandwidth demands of content providers, compute and storage networks for data centers must become flatter and more horizontally interconnected. Known as the “converged data center,” this flatter architecture is required to improve server-to-server and server-to-storage communication within the data center, which directly impacts latency and the quality of streaming services. In addition to delivering latency performance advantages, the converged data center architecture is highly scalable and lends itself to software virtualization of compute server and storage hardware resources, supporting rapid changes in service bandwidth demands. Some vendors refer to this architecture as Software Defined Networking (SDN).

To read more of this external content, go to: “Traditional Clock Tree Designs for Converged Data Centers Are Too Complex.” 

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