How to Build a Network to Support the Coming Video Boom
By Gary Lee
I’m at the Ethernet Technology Summit today to present on the fabric needs of FCOE data center switches (more on that in another post), and in looking over the keynotes for the show, I was struck by the number of discussions centered on video traffic.
It is clear that we are entering a world in which video distribution is becoming a key network traffic component. A 2009 report issued by Cisco stated that all forms of video are expected to exceed 90% of all consumer Internet traffic by 2013. To support this trend, though, switching infrastructure needs to efficiently support multicast traffic.
We’ve been anticipating this demand and considering what features need to be built into the switch to support this traffic. The FocalPoint family of 10GbE switch silicon has been architected with video distribution and multicast traffic in mind. FocalPoint’s output queued shared memory architecture queues multicast traffic only once, reducing internal switch congestion and memory requirements.
In addition, video traffic can be assigned a unique traffic class along with a dedicated memory partition in the switch, allowing it to be flow controlled separately from other data traffic using IEEE Priority Flow Control frames. This minimizes both video latency and traffic loss. At the switch egress, video traffic can be giving minimum bandwidth guarantees, which translates to bounded latency jitter.
Latency jitter is a key parameter in video distribution networks as it impacts the size of memory buffers required at the location where video is being reproduced, which in turn drives the cost of video distribution systems or set-top boxes. In addition to bounded latency jitter, FocalPoint can also operate in cut-through mode with absolute latencies around 200nS and P-P latency jitter of less than 50nS. All of this leads to cost savings for both the service provider and consumer.
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