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Hybrid packet/circuit data center networks extend IP functionality
The Internet protocol has been the dominant local area networking standard for decades. Now, IP is being put to its greatest test, as it is applied to real-time applications in the data center.
Some agencies are finding that when it comes to the low-latency, high-bandwidth needs that characterize data center networking, augmenting IP networks with layer-one networks brings significant bandwidth management, fiber-optic cable management and network operations advantages.
There are two primary circuit switch architectures to choose from: all optical switches that pass the data through the switch as light without any conversions, and optical-electrical-optical switches that convert an incoming fiber-optic signal into an electrical impulse for switching before converting it back to a fiber-optic signal.
Data passes through all optical switches without any caching, but data is cached during the OEO conversion process, and can be accessed by hackers if the switch is hacked. This makes the OEO switch a potential security concern.
With the advent of optical circuit switches based on 3D microelectromechanical systems (MEMS) technology -- which now supports 320 ports -- all optical circuit switching now has the port density needed for data center applications. 3D MEMS switches use a plane of micro mirrors that are moved by voltages applied to electrodes to move the mirrors to any desired position.
To give an idea of the mirror chip size, there are 384 mirrors on a one-square-centimeter area. The key benefits are high capacity, low power, fast switching times, low latency and low cost compared to traditional switching and routing OEO solutions.
Data center applications
All optical switches are finding a home in data center applications alongside packet switches in a hybrid circuit switched and packet switched network that brings low latency, any-to-any connectivity and automation of the physical infrastructure to the data center.
These advantages help agencies deal with the challenges brought by the explosion of traffic and large, dynamically changing traffic flows. When considering the increase in server virtualization, Web application traffic and the need to replicate vast amounts of data both internally and between data centers, optical circuit switching offers high bandwidth and configurability to ensure network capacity is available where it is most needed at any given time.
This network topology uses photonic switching to aggregate all of the top-of-rack IP switches located in server racks. This provides server cluster aggregation for intra data center traffic. The circuit switched fabric also connects servers to core routers for northbound WAN traffic between the data center and the Internet or WAN for a fully automated and dynamically reconfigurable physical infrastructure.
Looking forward, software defined networks (SDN) for hybrid circuit/packet networks will provide a management plane for topologies and configuration changes that analyzes the various traffic flows within the network in coordination with photonic and routing control planes.
All optical switches are making their way into government data centers to provide a secure aggregation fabric in a hybrid circuit/IP network that delivers low latency, fast performance and scalability.
Glenn Stern is vice president of global public sector for CALIENT Technologies. He can be reached at: