CALIENT Technologies

Move the light, not the fiber

Webinar Report: How Optical Circuit Switching works with SDN

The explosion of rich media data now underway is having a dramatic impact on data centers and is the driving force behind interest in software-defined networks (SDN), which is perhaps the hottest trend in networking today.

Hybrid Packet-Optical Circuit Datacenter NetworkBy combining SDN technology with optical circuit switching, data centers get the network control and agility that SDN promises, with the ultra-low latency and scalability of circuit switches. To help the industry better understand this concept, I joined several network industry leaders in a recent SDN webinar sponsored by industry publication Light Reading. Click here for an archive of the webinar.

During the presentation, I explained that the data explosion was overloading networks resulting in high latency and congestion that led to poor application performance.  One solution to minimize the impact of this is to design for worst-case scenarios, meaning that key switches and links are over provisioned to handle peak traffic. However this results in increased cost at a time when revenue from customers is essentially flat, so it’s not a realistic way forward.

This is where Optical Circuit Switching, together with Software Defined Networking enters the picture.  SDN effectively moves the control plane out of the Layer 2 and 3 switches and routers into an overlay control layer which has visibility across the entire network infrastructure layer. With appropriate algorithms in the control layer the available network resources can be optimized to better shape traffic flows in real time.

With SDN in place to manage the network, the next consideration is connectivity.  SDN controller technology can be used with optical circuit switches to build a low-latency network fabric that connects top-of-rack switches to core routers.

Photonic switches like the CALIENT S320 can facilitate any-to-any connectivity between servers in the data center with a link latency less than 60 ns – which is significantly lower than the several microseconds  offered by typical data center IP switches.   Because they are protocol agnostic, optical circuit switches can scale from 10 Mbps to beyond 100 Gbps without any change in optics.  One immediate advantage of this highly configurable fabric is that high bandwidth traffic can bypass the packet-based cluster aggregation network, as the optical circuit switch can set up a direct pure-optical links between ToR switches.

I finished my part of the webinar with a discussion of how to apply SDN and photonic switching to metro area service provider networks.  Look for a blog post soon on that topic.

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