Comcast notches 10G milestone with a trial of 1.25-Gig symmetrical speeds in Florida

Comcast is out of the 10G starter blocks with a trial in Florida that features symmetrical speeds of 1.26 Gbps on a live production HFC network.

The trial, which took place in a Comcast employee's home in Jacksonville, Florida, was the fruition of Comcast's ongoing work over the past several years on virtualzing its network and kicking the tires on virtual cable modem termination systems (vCMTS) and the cable industry's digital access architecture (DAA) initiative.

While Comcast has long been out front with its vCMTS efforts, Thursday was the first time it disclosed the location for one of its vCMTS deployments. Comcast has deployed DAA throughout the area, and said additional trials would take place in more homes across Florida in the coming weeks.

The employee trial in Jacksonville was notable because it blended numerous elements of where the cable industry is headed in terms of symmetrical 10G speeds down the road.

“The great strength of our network technology is that we will have the ability to scale these next-generation speeds to tens of millions of homes in the future without digging up yards, or starting massive construction projects," said Tony Werner, president of technology, product, Xperience at Comcast Cable, in a statement. "This technology provides a path to meeting the needs of the future and making multi-gigabit symmetrical speeds a reality for everyone, not just a select few.”

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Elad Nafshi

According to Elad Nafshi, senior vice President of next-generation Access technologies at Comcast Cable, Comcast used a "high split" for its trial to create headroom on the upstream to a range of 5 MHz to 204 MHz.

Comcast used remote PHY (RPHY) nodes from Harmonic that connected to a node+0 fiber deep architecture. Node+0 allows cable operators to eliminate amplifiers between the node and a home if they chose to do so.

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At the end of last month, Mediacom showcased its 10G Smart Home in Ames, Iowa, which also used DAA with remote PHY devices from both CommScope and Casa Systems.

"What makes this kind of unique is, first of all, this is relying on a platform that is now scaled and scaled quite broadly," Nafshi said. "So this is a fully virtualized CMTS with a software-defined network, leading to next generation digital RPHY nodes. Feeding, in this case, a node+0 fiber deep deployment."

For Comcast in particular, and the cable industry in general, the trial was a culmination of driving fiber deeper into neighborhoods, building the virtualization and software-defined network, working with Harmonic on the vCMTs deployments, building the cloud tools, and getting on board remote PHY and DAA early on.

"When you talk about really optimizing the customer experience from a delivery standpoint—reliability, and speed in this case—it's really how all the pieces come together," Nafshi said. "It's not just the virtual CMTS, which we're by far the leader. It's not just the adoption of DAA in our RPHY nodes, which again, we're by far the leader. It's the combination of all of these."

Comcast's Jacksonville trial is one step up on the 10G evolutionary ladder. Vendors are hard at work on developing new silicon and hardware for 10G. In an interview Wednesday with FierceTelecom, CommScope's Tom Cloonan, CTO for broadband networks, said 10G was a multi-year journey to reach the symmetrical 10G speeds in the 2023-2025 timeframe. With the DOCSIS 4.0 specs completed in April, Cloonan said there could downstream operations up to 1.8 GHz as early as next year.

The current crop of DOCSIS 3.1 modems can only get to a mid-split, but Nafshi said the next generation of modems will reach the needed high split.

In the meantime, Nafshi said there's still plenty of work to do to operationalize and broaden the 10G landscape.

"You need meters that are able to extend to the high end spectrum," he said. "You need a lot of operationalization on how do you do leakage detection?

"We've got all the platform plumbing working. When you extend to a customer, you need to make sure that you have all the operational tools and support that are required to really scale this up, and that's what we're working on."

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Comcast's announcement comes ahead of next week's virtual -SCTE/ISBE Cable-Tec Expo where 10G will be one of the hot topics

"I know that there are a lot of people that'll be talking about this stuff," Nafshi said. "But really, the difference here is that this platform that's feeding this trial is also feeding many large subscribers in parallel. This is not a proof of concept, it's not demoing.

"This is really the culmination of a great amount of work that's been going on over the last two to three years to really bring this vision of virtualization and DAA to live subscribers. We're reaping the benefit of that investment now."