Comcast first dipped its corporate toe into the ocean of network virtualization back in 2009 because it wanted to bring a better experience to its video subscribers. That led to the creation of its X1 platform, which delivers cloud-based IP video to subscribers on the device of their choice, whether TV, phone, tablet, or laptop.
While that all sounds mundane today, it was a major technical challenge when X1 was being created. Cable trade shows were rife with sessions about “multi-screen video.” And there were two camps: those that argued video would always be a “lean-back” experience, watching TV from the comfort of the couch; and those that weren’t so sure and seemed a bit panicked.
“Comcast dived into virtualization on the video side,” said Noam Raffaelli, SVP of network and communications engineering at Comcast, in an interview with SDxCentral. “Back then, we created the RDK initiative, which is all about creating an abstraction layer between hardware and software.”
Comcast initially drove the cable industry’s Reference Design Kit (RDK) initiative. It is an open-source software distribution that provides a common framework for powering customer-premises equipment (CPE) such as set-top boxes, cable modems, and Internet routers.
“The RDK initiative enables software vendors and hardware manufacturers to integrate their wares with Comcast’s reference design,” said Raffaelli. “That was the first instance where we as a company realized that separating the hardware and software and creating an abstraction layer would benefit our customers.”
Comcast’s reference design enables the company to easily feed its video ecosystem with its latest development. “We are operating our video platforms in DevOps mode,” said Raffaelli. “We are feeding thousands of changes on a weekly and monthly basis.”
While X1 was Comcast’s first virtualization foray, the cable company has built other virtualization platforms for major services over the past several years. These virtualized platforms help it deliver IP multi-media subsystems (IMS) services, voice, and residential email, for example.
Comcast’s Virtual Network
The company has built data centers across its footprint to host these platforms. And it runs OpenStack for cloud management in those data centers.
“We want to use OpenStack where applicable,” said Raffaelli. “But we are not locking in with one technology. Different use cases and services will potentially require different technologies. We are also using public clouds.” Specifically, Comcast is working with Amazon Web Services (AWS) and Microsoft Azure.
For its software-defined networking (SDN) controller, Comcast uses the Open Network Operating System (ONOS). About a year ago it joined the ONOS project and the Central Office Re-architected as a Datacenter (CORD) project. At the time, the projects were led by On.Lab, which has since merged with the Open Networking Foundation (ONF).
Raffaelli added that Comcast is also looking at ONF for a virtual fiber function. And it’s working with ONF and CORD in relation to its cable-specific access technologies.
For its software-defined wide area networking (SD-WAN) service, Comcast uses Versa Networks’ technology. Comcast Business recently announced a software-defined networking (SDN) platform named ActiveCore. And Comcast’s SD-WAN will be the first business product powered by the ActiveCore platform.
Asked about the “people factor” and whether Comcast had experienced a lot of pushback from employees as it transitions from tons of customized hardware to more generic hardware with open source software, Raffaelli indicated it hadn’t been a big problem.
“The culture we started to instill with X1 was a good starting point,” he said. “The abilities that the separation of software present to us land well with our engineers. The engineers see the benefit in that. The X1 as a success story definitely helped. We are trying to get more software engineers into our network organization.”