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Technology enablers for Cloud DCI

Many CSPs already provide a wide range of optical data center interconnect (DCI) services. These include dark fiber, managed and unmanaged wavelengths and carrier Ethernet. IP DCI services are also becoming important to interconnect cloud-based data centers.

Data centers are becoming more virtualized and automated through the deployment of software-defined networking (SDN). As a result, there is a need to extend virtualization and SDN between data centers in private, virtual private, hybrid and public clouds.

CSPs are ideally placed to help all participants in the new cloud ecosystem to connect their distributed cloud data centers. They can also take advantage of the cloud opportunity by offering new cloud DCI services.

Cloud data centers demand a new approach to data center interconnect

Clearly, CSPs need a new approach to data center interconnect that matches the agility, flexibility and lower costs offered by the cloud model. Cloud data center interconnect (cloud DCI) provides such an approach:

  • It offers scalable, cost-effective bandwidth with high performance, reliability and low latency. It also offers security, QoS and end-to-end management to run business-critical applications in the cloud – characteristics that the Internet cannot provide
  • It provides the ability to increase and decrease bandwidth as needed, with multi-site and multi-technology capabilities to help share data, distribute applications and balance workloads
  • Most importantly, it provides agile, dynamic provisioning with support for orchestration of network resources quickly and easily, particularly across multiple cloud types and administrative domains in the cloud ecosystem

The opportunity for cloud DCI

A previous article, Cloud interconnect - new revenues from cloud DCI, outlined the new cloud ecosystem, the central role of CSPs and the opportunities to increase revenues and drive profits, as shown in Figure 1.

Figure 1. The cloud ecosystem and the role of CSPs

With cloud DCI, CSPs can:

  • Offer direct connect and managed DCI services to connect multiple enterprise customer data centers in private, virtual private and hybrid clouds
  • Deploy data center gateways to extend customer data center virtualization over IP/MPLS services and connect remote sites and end users to applications in the cloud
  • Connect distributed data centers and repurposed central offices to deploy NFV and SDN, optimize resource pools and improve efficiency when delivering cloud services
  • Expand footprint to reach more customers by collocating in carrier neutral provider (CNP) co-location facilities to create cloud interconnect and exchange points

However, CSPs must ensure their cloud DCI services are more scalable, agile and flexible than traditional DCI services if they are to make the most of the opportunity presented by the dynamic nature of the cloud.

Key requirements for cloud DCI

Cloud DCI has some specific requirements compared to traditional DCI, including:

  • Scalable, flexible, secure bandwidth: It needs to support very scalable, secure bandwidth that can be increased and decreased as needed, as well as Ethernet and IP capabilities for different cloud applications
  • Multi-site, multi-technology, multi-cloud capabilities: It must enable data to be shared, applications to be distributed and workloads to be balanced workloads across different cloud types, between multiple locations and between different cloud providers
  • Agile, dynamic provisioning: It needs to support orchestration of network resources across cloud boundaries — between different locations, across multiple data centers and across different types of cloud and cloud provider

Scaling cloud DCI services

The demand for higher speed services and growing dependency on cloud services are creating new demand for 100G connectivity. 100G is being deployed for applications such as data center interconnect and CSPs therefore need to be able to deliver end-to-end 100G services.

Super coherent optics incorporates technologies that balance wavelength capacity and distance so that CSPs can maximize the efficiency of their fiber networks. These technologies include:

  • Variable modulation that supports different optical modulation formats. Increasing the bits/symbol by moving to higher order modulation can increase fiber capacity. The CSP can select the modulation that best aligns with their fiber capacity and reach needs
  • Flexible baud rate. This is how fast the symbols of a given modulation format are transmitted. Higher baud rates enable higher capacity and better performance by allowing the use of less complex modulation schemes
  • Advanced coding: This provides digital manipulation of the bit stream to improve performance, and includes techniques such as soft-decision forward error correction (SD-FEC)
  • Flexile spectrum. This provides optical filtering that allows extremely tight wavelength spacing to form very high bandwidth super channels with maximum optical and spectral efficiency

Securing cloud DCI connections

Data security and integrity, as well as regulatory compliance, are critical considerations when organizations make decisions about cloud DCI services, particularly for applications such as business continuity and disaster recovery (BCDR).

Secure optical transport provides an ideal way to protect the connections between cloud data centers. Some key features required for secure optical transport include:

  • Layer 1 encryption: In-flight data encryption at layer 1 is faster and more bandwidth efficient with less overhead and low latency than encryption at higher layers
  • AES 256 bit encryption using symmetric keys: This approach provides highly secure data encryption and is generally accepted to be safe against quantum computing attack
  • FIPS 140-2 Level 2 and CC EAL2+: These independent security certifications signify that the solution has satisfied a rigorous set of internationally recognized security standards
  • Centralized key management: Managing the encryption keys centrally is more scalable, efficient and secure as it establishes a single point of trust
  • Separate device and security management: This allows the CSP to manage the network devices and cloud DCI service, and their customers’ security teams to manage the keys

Multi-site, multi-cloud connectivity

Organizations want to connect to multiple cloud data centers and different cloud types. For example, they want to run business-critical applications in a private cloud and connect to data center resources in hybrid clouds when they need additional capacity.

CSPs can provide multi-site, multi-cloud connectivity by leveraging managed IP/MPLS-based Ethernet and IP VPN services to:

  • Provide regional, national or international connectivity between cloud data centers for applications with less stringent latency or lower bandwidth requirements
  • Connect enterprise remote site access to applications hosted in cloud data centers, or to integrate with the enterprise’s existing private WAN
  • Offer a choice of advanced IP/MPLS-based cloud DCI services, such as Layer 2 Virtual Private LAN Service (VPLS), MEF CE 2.0-certified services and Layer 3 IP VPNs
  • Quality of Service (QoS) with granular control of applications, advanced traffic engineering and link redundancy to meet strict cloud service-level agreements (SLAs)

Deploying cloud services seamlessly

One of the attractions of cloud is to distribute applications and balance workloads dynamically between cloud data centers and to make more efficient use of resources. A key requirement is to extend server virtualization and simplify VM mobility by extending SDN over the WAN.

In SDN-enabled data centres, network virtualization overlay technology such as VxLAN enables VPNs for multi-tenancy, VM mobility and improved resource allocation. Data center gateways provide seamless interworking between data center SDN platforms and L2/L3 WAN technologies through seamless integration of control, data and management planes. Using data center gateways, CSPs can:

  • Enable auto-instantiation of policy-based services and extension of resources between SDN-based data centers over the WAN
  • Provide seamless connectivity between compute and storage resources across multiple data centers on the same or different IP subnets using different encapsulation schemes
  • Enable full integration of data centers and IP VPN services for seamless connectivity between enterprise data centers and end users in branch office locations

Automating and optimizing cloud DCI

Another key technology enabler for cloud DCI is automated service provisioning.  Achieving automation in today’s networks requires layer by layer, domain by domain integration. This is costly, not very agile or flexible, and a serious problem for service innovation and delivery.

Carrier SDN solutions solve this problem by enabling a more dynamic and responsive network. Instead of a layer by layer, domain by domain approach to automation, carrier SDN handles the complex task of provisioning multi-domain IP/optical networks. It provides a more agile and flexible approach to enabling dynamic cloud DCI services. For example, carrier SDN can automate and optimize the network by:

  • Using policies for time-sensitive applications that need network paths with the lowest latency and congestion. The policy can switch to the best path available if congestion occurs or more bandwidth frees up
  • Providing the resilience required by calculating two paths for each service request, a forward or primary path that is distinct from the return or backup path
  • Allocating stranded bandwidth in real-time. For example with a real-time view of paths and bandwidth, carrier SDN can identify free bandwidth and move an existing path dynamically, freeing up bandwidth to enable new connections
  • Tuning the network dynamically. For example, a link might become congested, triggering a policy to assign more bandwidth when a threshold is crossed, such as adjusting bandwidth or changing ODU size to avoid service degradation


As data centers and IT move to the cloud. CSPs are ideally placed to offer cloud DCI services to the different cloud participants and thereby drive additional revenues and profitability.

But cloud DCI solutions need to support a mix of technologies to enable scalable, agile and flexible services across multiple clouds.

CSPs need to deploy cloud DCI solutions that provide the flexibility, scalability and security to support current DCI needs — along with the capacity, performance and agility required to support dynamic services across different cloud types. For information about Nokia’s cloud DCI solutions, click here.

Gary Holland

About Gary Holland

Gary is responsible for marketing Nokia's IP and Optical Networks (ION) portfolio to Enterprise, Industries, Government and Public Sector verticals, both direct and through Global Alliance partners. With more than 25 years’ experience in the telecommunications industry, Gary has held senior roles in corporate, portfolio and product marketing, partner and business development and product line management with technology companies including Alcatel-Lucent, Riverstone Networks and Digital Equipment. Gary brings a combination of marketing, partner development and technology expertise to his current role at Nokia.

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