Perspective: Race to the Edge

As we start to explore how softwarization is transforming the network, we should recognize that it is the access network that connects homes, businesses, and mobile users to the Internet that is undergoing the most radical change. The fiber-to-the-home and cellular networks described in Section 2.8 are currently constructed from complex hardware appliances (e.g., OLTs, BNGs, BBUs, EPCs). Not only have these devices historically been closed and proprietary, but the vendors that sell them have typically bundled a broad and diverse collection of functionality in each. As a consequence, they have become expensive to build, complicated to operate, and slow to change.

In response, network operators are actively transitioning from these purpose-built appliances to open software running on commodity servers, switches, and access devices. This initiative is often called CORD, which is an acronym for Central Office Re-architected as a Datacenter, and as the name suggests, the idea is to build the Telco Central Office (or the Cable Head End, resulting in the acronym HERD) using exactly the same technologies as in the large datacenters that make up the cloud.

The motivation for operators to do this is in part to benefit from the cost savings that come from replacing purpose-built appliances with commodity hardware, but it is mostly driven by the need to accelerate the pace of innovation. Their goal is to enable new classes of edge services—e.g., Public Safety, Autonomous Vehicles, Automated Factories, Internet-of-Things (IoT), Immersive User Interfaces—that benefit from low latency connectivity to end users, and more importantly, to the increasing number of devices those users surround themselves with. This results in a multi-tier cloud similar to the one shown in Figure 55.


Figure 55. Emerging multi-tier cloud includes datacenter-based public clouds, IXP-hosted distributed clouds, and access-based edge clouds, such as CORD. While there are on the order of 150 IXP-hosted clouds worldwide, we can expect there to be thousands or even tens of thousands of edge clouds.

This is all part of the growing trend to move functionality out of the datacenter and closer to the network edge, a trend that puts cloud providers and network operators on a collision course. Cloud providers, in pursuit of low-latency/high-bandwidth applications, are moving out of the datacenter and towards the edge at the same time network operators are adopting the best practices and technologies of the cloud to the edge that already exists and implements the access network. It’s impossible to say how this will all play out over time; both industries have their particular advantages.

On the one hand, cloud providers believe that by saturating metro areas with edge clusters and abstracting away the access network, they can build an edge presence with low enough latency and high enough bandwidth to serve the next generation of edge applications. In this scenario, the access network remains a dumb bit-pipe, allowing cloud providers to excel at what they do best: run scalable cloud services on commodity hardware.

On the other hand, network operators believe that by building the next generation access network using cloud technology, they will be able to co-locate edge applications in the access network. This scenario comes with built-in advantages: an existing and widely distributed physical footprint, existing operational support, and native support for both mobility and guaranteed service.

While acknowledging both of these possibilities, there is a third outcome that is not only worth considering, but also worth working towards: the democratization of the network edge. The idea is to make the access-edge cloud accessible to anyone, and not strictly the domain of incumbent cloud providers or network operators. There are three reasons to be optimistic about this possibility:

  1. Hardware and software for the access network is becoming commoditized and open. This is a key enabler that we were just talking about. If it helps Telcos and CableCos be agile, then it can provide the same value to anyone.

  2. There is demand. Enterprises in the automotive, factory, and warehouse space increasingly want to deploy private 5G networks for a variety of physical automation use cases (e.g., a garage where a remote valet parks your car or a factory floor making use of automation robots).

  3. Spectrum is becoming available. 5G is opening up for use in an unlicensed or lightly licensed model in the US and Germany as two prime examples, with other countries soon to follow. This means 5G should have around 100-200 MHz of spectrum available for private use.

In short, the access network has historically been the purview of the Telcos, CableCos, and the vendors that sell them proprietary boxes, but the softwarization and virtualization of the access network opens the door for anyone (from smart cities to underserved rural areas to apartment complexes to manufacturing plants) to establish an access-edge cloud and connect it to the public Internet. We expect it to become as easy to do this as it is today to deploy a WiFi router. Doing so not only brings the access-edge into new (edgier) environments, but also has the potential to open the access network to developers that instinctively go where there are opportunities to innovate.

Broader Perspective

To continue reading about the cloudification of the Internet, see Perspective: Virtual Networks All the Way Down.

To learn more about the transformation taking place in access networks, we recommend: CORD: Central Office Re-architected as a Datacenter, IEEE Communications, October 2016 and Democratizing the Network Edge SIGCOMM CCR, April 2019.