NEW ORLEANS – After years of trials and tribulations, Comcast has begun rolling out network virtualization in a big way, becoming the first large cable operator in North America, possibly the world, to do so.
Speaking in various forums at the SCTE/ISBE Cable-Tec Expo show here earlier this month, Comcast executives said they have now commercially deployed a virtualized form of their cable modem termination system (CMTS) platform in a growing number of U.S. markets, with many more still to come.
So far, these virtual networks are serving more than 100,000 of the company's nearly 26 million residential broadband customers. “We're rolling at a pretty steady pace," said Tony Werner, Comcast's president of technology, product and Xperience, told Light Reading during an interview at the show.
Company officials declined to specify how fast the company is rolling out the new technology or when deployments will be complete, but they indicated it will take time to carry out the nationwide deployments to their 50-million-home footprint.
"One of the things we're most proud of and a challenge here is the reliability of our network," said Matt Zelesko, Comcast's SVP and chief technology officer. "We don't want to do anything to sacrifice that customer experience, sacrifice that reliability. It's been a very measured approach."
Like other cablecos and telcos, Comcast is pursuing network virtualization to boost the capacity and efficiency of its hybrid fiber-coax (HFC) access networks, as well as streamline its overall operations and cut costs. Among other things, the move is central to the cable industry's ambitious push to offer symmetrical speeds of at least 10 Gbps to broadband subscribers in the near future.
Virtualization has become "critical" for transforming how Comcast runs its access network, said Jan Hofmeyr, executive vice-president and chief network officer at Comcast. He added "the complexity is increasing as we are scaling."
Specifically, what Comcast is doing is combining a software-based, containerized "virtual" CMTS (vCMTS) with a distributed access architecture (DAA) that shifts critical processing and electronics from the cable headend to the access network edge. As part of this move, the big U.S. cable operator has so far deployed several thousand remote PHY nodes at the network edge to support the more intelligent networks.
“A virtual network can guide the capacity where the capacity is needed… and that changes during different times of the day.” – Elad Nafshi, Comcast
"A virtual network can guide the capacity where the capacity is needed… and that changes during different times of the day," said Elad Nafshi, senior vice president of next-generation access network at Comcast.
Besides the benefits cited above, company officials said the virtualization drive is reducing rack equipment and cutting down power requirements, too. Further, this generation of more real-time telemetry data from the virtualized network is slashing the mean time needed to detect network issues from 30 minutes to a mere 15 seconds. "This truly is a completely new ecosystem… and approach," Nafshi added.
Instead of leveraging purpose-built CMTS chassis, Comcast's virtual access network places key network functions in powerful new software which runs on off-the-shelf computer servers. The cableco says this shift will slash its number of hub sites and power and cooling requirements over time, as well as produce other economic and operational benefits.
To cite one example, the execs said Comcast can now make software changes simply from a computer console, without needing to physically switch out a CMTS card in the cable headend. “It's a big change to go from CMTS appliances to – all of the sudden – a cloud-based architecture with COTS [commercial off the shelf] hardware and running Kubernetes and powering this from a few data centers, versus having CMTSes out deep in the hubs and the headends," Werner said.
Comcast’s leaders also believe their new virtualized infrastructure with real-time data analytics will enable the company to pinpoint network problems quickly and make sure any service outages are confined to a very small number of customers. Indeed, officials estimate that their new architecture will limit network failure points to the number of homes served by a single fiber node, or about 40 customers, as opposed to the 20,000 to 30,000 customers often served by nodes through a traditional CMTS.
"Long term, we firmly believe this will actually be more reliable and allow us to upgrade faster and do things significantly faster," Werner said. "We have tremendous redundancy – more redundancy than what we've had in the past."
