Arista Data Center Interconnect Solutions – Next-Generation 7500R 200G Coherent DWDM Platform


The latest smartphone app, mobile game, instant messaging tool or video sharing site hits the media, and all of a sudden everyone over the age of 20 discovers what the under-20’s have known for a while and download, install, use and share it. This trend repeats and repeats. This is the modern world of mobile, cloud networks and mega-scale datacenters. Keeping up with the latest trends is not just a problem for those old enough to remember texting with numeric keypads but also for the operators of these datacenters.


More content, in more locations and at significantly faster speeds is driving an explosion in bandwidth of unprecedented proportions that is in turn fueling innovation in the technology that supports it. The requirement to both scale up and scale out the datacenter has driven unprecedented growth in high speed datacenter leaf and spine networks, with the latest switches offering multiple terabits of performance from a single silicon chip. Hundreds of Terabits per second of switching and routing are now possible in a single system supporting hundreds of ports at speeds of up to 100 Gbps on a single connection. An often overlooked piece of the puzzle is the connectivity between these sites. Addressing the huge bandwidth requirements for interconnecting multiple locations and transporting information over long distances is where Data Center Interconnect, or DCI, technology is focused.


Data Center Interconnect (DCI)

To keep up with the growth and data frenzy, many cloud service providers have resorted to a practical approach to scaling: fragment the mega-scale datacenter into a number of smaller and more manageable sites in a metro region and connect them so that they are effectively acting as one large, unique entity. Obtaining seamless connectivity between these locations requires multiple connections in parallel all running at the highest speed available. Distances between sites may vary from a few kilometers to hundreds of kilometers due to fiber routing, and solutions are available to multiplex connections on single fibers. The challenges do not stop when connecting between regions. As distances increase, the availability of fiber gets more challenging and being able to multiplex even more connections using advanced modulation onto a single fiber is essential to maximize the potential capacity of the fiber and control costs.


Arista Coherent Linecard

To answer the call to deliver the highest capacity over the longest distances for Data Center Interconnect is Arista’s newest coherent optical line card for the Arista 7500R Series. With support for advanced modulation allowing 200Gbps per wavelength and up to 128 wavelengths over the C-band, for up 25.6Tbps per fiber, the DCS-7500R-8CFPX coherent line card integrates state of the art packet processing switching silicon technology with the power of advanced coherent digital signal processing (DSP) units directly on-board and full support for wirespeed MACsec encryption. The combination of wirespeed layer-2 and 3 packet processing, advanced DSP and MACsec encryption with simple plug and play analog coherent CFP2 optics has enabled the industry’s highest density solution for secure, coherent optical interconnections.


Arista 7500R-8CFPX coherent linecard

Arista 7500R-8CFPX coherent linecard

Each port on the module can be independently configured to a choice of 100, 150 or 200 Gbps of modulated coherent light that is simultaneously encoded in phase, amplitude and polarization and is wavelength-tunable within a 5 THz spectral window. A single 7500R Series system allows datacenters as far apart as Los Angeles and Tokyo to be interconnected with a single fiber pair and multiple terabits per second of bidirectional traffic with PM-QPSK.


The Arista Coherent Optical Solution dramatically lowers both CapEx and OpEx for cloud datacenter operators compared to non-integrated DWDM solutions and provides simple, reliable and secure solutions to the high bandwidth needs of cloud DCI.

The Arista Coherent technology is being showcased at OFC 2017, and you can learn more by reading the following papers.

  1. Lessons Learned from CFP2-ACO System Integrations, Interoperability Testing and Deployments.
  2. Interoperation of Layer-2/3 Modular Switches with 8QAM/16QAM Integrated Coherent Optics over 2000 km Open Line System.
  3. Transmission Performance of Layer-2/3 Modular Switch with mQAM Coherent ASIC and CFP2-ACOs over Flex-Grid OLS with 104 Channels Spaced 37.5 GHz.


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