Data Center Interconnect (DCI) technology connects two or  more data centers together over short, medium, or long distances using  high-speed packet-optical connectivity.

Data Centers house compute and storage resources for  applications, data, and content.  And in  this cloud-based, application-centric world, access to that data is a critical  challenge.

Data Centers need to talk to each other—to share data and  content and provide back-ups for redundancy. Fortunately, DCI technology  enables the transit of critical assets over any distance, from across town to ultra-long  trans-Pacific or trans-Atlantic oceanic links and everything in-between. Data  may be carried across simple, point-to-point connections, more robust  ROADM-based networks, or open line systems which support transport interfaces  sourced from multiple vendors.

An image showing distance requirements for DCI applications vary from metro to subsea
Distance requirements for DCI  applications vary from metro to subsea

The most effective transport technology for DCI is next-generation  coherent optics providing blazing speeds up to 800 Gb/s per wavelength. With a fast,  reliable connection in place, physically separate data centers can easily share  resources and balance workloads.

Some large operations use DCI to connect their own data  centers within their extended enterprise infrastructures, while others connect  to partners, cloud providers or data center operators to simplify data and  resource sharing or handle disaster recovery needs.  Subsea cables are used to connect data  centers and internet exchanges between countries and continents separated by vast  oceans.

Some DCI applications need the highest level of capacity and  scalability along with more software control and automation, while others can trade  off some performance to meet a specific power profile and form-factor.

Performance optimized DCI solutions are needed to overcome  scalability and distance constraints to deliver higher capacity connectivity.

An image showing that increasing capacity and distance are key challenges for DCI networks
Increasing capacity and distance are  key challenges for DCI networks

  • Distance: DCI applications can vary  greatly in size and scope. Data centers may be dispersed across a metro area,  around a country, or all over the globe.   Having enough performance to interconnect them while carrying the most  bits the farthest is critical. Performance optimized coherent technology can transport  more capacity at any distance, offering programmable interfaces with selectable  baud and different modulation schemes to fine tune capacity for any application.  In addition, for ROADM-based networks that  provide greater flexibility and resiliency, performance optimized solutions offer  the capability to transit multiple ROADM nodes across short metro links, as  well as long-haul haul routes between major cities.
  • Capacity: Data centers store and deliver  the data that applications require. Data sets coming into or leaving a data  center can be very large—from hundreds of Gigabits to Terabits.  Routers are moving from 100GbE to higher  speed 400GbE services. To handle these growing bandwidth demands, networking  equipment must provide reliable, high-capacity connections that scale simply  and quickly. Coherent optics, like  Ciena’s WaveLogicTM  5, pave the way for data to move at rates up  to 800 Gb/s  on  a single wavelength, increasing DCI capacity to a new industry benchmark.  Furthermore, modern photonic line systems offer the ability to expand the  usable spectrum from the C-band to include the L -band  for double the capacity per fiber, allowing more wavelengths between data  centers in fiber constrained or high growth areas.

Footprint optimized DCI solutions shrink the size of the coherent  Digital Signal Processor (DSP) and electro-optics to fit within a  standards-based pluggable form-factor.   These pluggable interfaces provide IP/Optical integration without reducing  faceplate density or stranding packet switching capacity.  Footprint optimized solutions are attractive  for access, edge, and metro DCI applications where spectral efficiency is less  of a concern and service density, reduced power consumption, and smallest footprint  are critical.

In addition to distance and capacity concerns, DCI networks  face challenges associated with data security, simplifying operations, and  reducing the cost per bit for connectivity.

Image showing additional requirements commonly seen for DCI networks
Additional requirements commonly seen  for DCI networks

  • Security: Sensitive information is often stored  in data centers. Financial transactions, personnel records, and other corporate  data are all crucial and often highly confidential. As a result, DCI must be  reliable, safe, and even encrypted to avoid costly breaches and data losses.  Encryption and stringent rules for access to stored data are widely deployed to  protect against intrusions, and advances in packet-optical networking equipment  can deliver wire-speed, in-flight encryption to protect data as it travels over  an optical DCI link.
  • Operations: Minimizing the labor,  complexity, slowness, and errors that arise from manual operations for  commissioning, provisioning, and managing the DCI network is an operational  imperative. Turning up a connection between two data centers must be simple and  fast, and managing each connection should not require ongoing manual tasks. Standards-based  open APIs and modern data models are critical to the shift to automation  because they enable platform integration, scripting, and new ways to monitor  and manage the network. Optical networking platforms designed and purpose-built  for DCI applications can be managed through open interfaces or full lifecycle  management software platforms, giving network operators the flexibility to  manage the DCI network the way that they want.
  • Cost: Large data streams entering and  leaving data centers must be carried as cost-efficiently as possible, so  lowering the cost per bit for interconnect is an ongoing concern. To reduce  interconnect cost/bit while offering more capacity scalability, the industry is  making advances in high-speed coherent interfaces to increase capacity per  wavelength and improve performance to drive those bits longer distances.  Additionally, compact, modular interconnect  devices, such as Ciena’s Waveserver® family of products, are designed to minimize  footprint and power requirements and reduce ongoing operational costs across  the lifetime of the DCI system.

DCI technology sits at the center of the cloud-centric world,  providing the network capacity for users and applications to connect to  storage, compute, and content resources.

Ciena offers best-in-class coherent optics with performance  optimized and footprint optimized solutions to fit any DCI application space, packaged  in a way that is simple to use, scalable, and tailored to each network’s needs.