In our previous post, outlining the preconditions of technological change and innovation in the Telco industry, we explored the emergence of CORD, the Central Office Re-architected as a Data Сenter reference network architecture. This approach to central office modernization enables service providers to cut costs and achieve flexibility by turning their switching facilities into agile data centers. Importantly, CORD can be applied to different types of networks, such as residential (R-CORD), enterprise (E-CORD), and mobile (M-CORD), utilizing common commodity hardware and open source software components.

Today we are going to focus on R-CORD, the largest use case opportunity from deployment volume perspective, as well as outline its most popular implementation scenarios from the subscriber’s, service provider’s and third-party content provider’s points of view.  

What is R-CORD?

Residential CORD is one of the targeted applications of CORD, designed specifically to transform the edge of the provider’s networks into an agile service delivery platform, allowing operators to introduce innovative features, provide the best end-user experience and improve customer self-service.

While specialized access hardware is required to physically connect subscribers (via GPON, DOCSIS or G.fast), R-CORD allows abstracting this purpose-built equipment and make it manageable by software defined networking (SDN) protocols (OpenFlow, P4RT and others). This approach envisions a big picture of Everything-as-a-Service (XaaS), which refers literally to everything that can be offered as a cloud-based connectivity service. The examples are virtualized customer premises equipment (vCPE) or virtual subscriber gateway (vSG), virtualized optical line termination (vOLT), and virtualized broadband network gateway (vBNG) or virtual router (vRouter).

R-CORD disaggregates CPE to vCPE, also referred to as vSG, moving most of the functionality of the original CPE into central office and reducing customer home device to a bare-metal gateway. Each vSG container corresponds to a subscriber bundle, the set of which implements subscriber-as-a-service.

The vCPE use case provides the opportunity for Telco companies to reduce the cost of expensive special-purpose hardware operated on a customer site with standard servers running software appliances. This allows them to diversify their service offerings, enabling rapid introduction of new services and significant reduction of their delivery costs.

Access-as-a-service is provided by virtualized OLT (vOLT), implemented as a combination of merchant silicon, SDN and network function virtualization (NFV) with control application running on top of ONOS. This application establishes and manages virtual local area networks (VLANs), connecting consumer devices, such as smartphones or tablets, and the central office switching fabric.

A traditional BNG device, initially used as a gateway to a central office, has also been replaced with its virtual counterpart, providing the necessary routing functionality to connect a subscriber to the Internet in a disaggregated manner. This virtualized BNG or vRouter is implemented as a network control application running on ONOS that manages flows through the switching fabric, providing Internet-as-a-service.  

As mentioned earlier, the basic set of software and hardware components is the same for all targeted configurations of CORD, what changes is only the type of traffic being processed. For this reason, different configurations utilize different types of virtual network functions (VNFs), the performance of which can be accelerated, enabling service providers to enhance the capacity of their networks. This acceleration can be performed via implementation of the offload techniques for NFV using DPDK-enabled and P4-programmable SmartNICs.

R-CORD Users

So now that we have defined what R-CORD is and what services it enables, let us see how it can be practically implemented in real-life use cases. As the key beneficiaries of this approach are service providers, residential subscribers, and third-party providers, we will highlight the key capabilities R-CORD can offer to each of them.

Service providers are constantly looking for ways to speed up innovation and decrease development time for new features to satisfy their data-hungry customers. Leveraging SDN and NFV, R-CORD provides operators with the opportunity to implement new behaviors in software and create systems that do not need new standards to function, enabling the following options:

  • Portal for service monitoring, management and provisioning
  • Virtualized access and virtual CPE
  • Innovative services:
    • Access-as-a-service
    • Subscriber-as-a-service
    • Internet-as-a-service
    • Content delivery-as-a-service
    • Firewall, URL Filtering, Parental Control

Subscribers do not really care about the technologies, but they do value the impact of CORD, as it results in new services for them, such as:

  • Subscriber portal enabling simple sign on, configuration and customization of services
  • Simple and easy to install home equipment that replaces complex CPEs
  • Internet, Firewall and Parental Control services

Additionally, the CORD infrastructure significantly simplifies the cooperation of service providers and third parties, allowing the latter to offer innovative service to common customers by empowering third-party providers with the following capabilities:

  • Expanding delivery for their own content into the services provider’s network
  • Third-party provider portal for managing services

Now let us dig a little deeper and consider the user scenarios of R-CORD to showcase the value it can deliver to each group of its end users.

R-CORD Use Cases

On-demand services. As the digital age makes it incredibly easy for kids to reach online content, parents nowadays are looking for tools to gain more control over what their children have access to. Imagine a family consisting of parents and a son. A son spends all his time surfing around social media sites, which makes his parents annoyed. Therefore, his father decides to apply access restrictions. After having logged in to the subscriber’s portal, he sees all the users in his home network but is unable to manage their web access rights. To activate this option, the father needs to change his subscription bundle and buy the one enabling parental control. Once he applies a new bundle and goes back to the user list, he sees a new column with all the parents’ filters set up and can block social media access for his son. This is how CORD enables residential subscribers to get services on demand.

Faster time-to-service. R-CORD empowers content providers to cache content closer to their customers and, consequently, deliver it to them faster. Previously, when the content was downloaded from outside the cache network, it was done very slowly, at the speed of few kilobits per second. On the contrary, when it is downloaded from the CORD network, the speed is significantly higher, because the content has been cached in the central office. This allows content providers to increase time-to-service, delivering high-quality video and other content to subscribers quicker than ever before.

Scalability and value-added services. By adopting the CORD architecture, service providers would be prepared for the future challenges related to the delivery of high-bandwidth services. The deployment of virtualized caches in Telco central offices provides the opportunity to dynamically scale out and scale in their caching capacity in minutes instead of months, as it was before. This is particularly valuable for peak events, such as live streaming of popular TV shows or important sport matches, that require significantly more bandwidth for a certain duration of time.

R-CORD also enables providers to add value to their core services. Returning to the case with parental control, we can now view it from a service provider’s perspective. The CORD approach makes it much easier to deploy device-level parental control by integrating the service with vSG or vCPE, which allows a “head of the household” to set different levels of access for each home device and block them against certain types of content. This is a service that can be bundled as a value-add to basic Internet access.

What’s Next?

R-CORD has already showcased its potential for the Telco market. Although the architecture is still under development, it certainly has benefited the major players of the industry. R-CORD not only enables new capabilities for service providers, opening up new business opportunities for them, but also delivers direct value to their residential customers, allowing the latter to quickly and safely configure and manage service packages. As the CORD Project’s mission is to develop a flexible, agile and open source framework to help telecommunication companies re-architect their traditional central offices, its existing set of pre-integrated releases (e.g. M-CORD, E-CORD) will be expanded to deliver solutions for various operator use cases. This is, however, a whole different story.

Yuriy Gordynskyi

Yuriy Gordynskyi

Networking Software Engineer at PLVision
Iurii has been working in the networking and embedded systems domains for almost three years and has contributed to the SAI (Switch Abstraction Interface) project. Among his interests Iurii singles out SDN paradigms.
Yuriy Gordynskyi

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