DOCSIS 4.0 has been billed as the technology that will put cable operators on par with 10G PON service from fiber providers, but a recent CableLabs interoperability event showed cable companies can hit over 8 Gbps with a mix of new and old gear.
CableLabs Principal Architect Doug Jones told Fierce Telecom that during a DOCSIS 4.0 interoperability event held at its facilities in Denver last month, operators demonstrated speeds of “eight point something” gigabits per second downstream and 1.5 Gbps upstream. But rather than using an end-to-end DOCSIS 4.0 system, this was done using a DOCSIS 3.1 cable modem termination system (CMTS) in a high split configuration and a DOCSIS 4.0 modem. The trick, he added, was getting these two pieces of equipment to talk to each other.
“The CMTS needs new software. The 3.1 CMTS needs to know what a 4.0 modem is” and what it’s capable of, Jones explained. “The CMTS needs to be able to understand that, negotiate those capabilities and send a set of capabilities back to that modem” to make it operational on the network.
CableLabs and partners including Arcadyan, Casa Systems, Cisco, CommScope, Harmonic, Sagemcom, Ubee, Vantiva and Vecima were able to work through those issues at the July event, Jones said. Among other things, they were able to get the 4.0 modems registered with 3.1 CMTS systems and both pieces of equipment to recognize new channels for data transmission. They were also able to validate the aforementioned speed performance metrics.
Rather than a replacement for end-to-end DOCSIS 4.0, Jones said this hybrid DOCSIS 3.1 CMTS+DOCSIS 4.0 modem setup can serve as a stepping stone to it, especially for smaller, regional operators who aren’t on the bleeding edge of the developing technology. It’s also more economical and less of a lift than deploying a DOCSIS 4.0 CMTS in terms of the amount of back office work required given operators would only need to install a software upgrade to their existing DOCSIS 3.1 CMTS system to deploy the 4.0 modems rather than validating and deploying an entirely new system.
The interoperability testing “builds confidence to get these [DOCSIS 4.0] modems out quickly because changing a CMTS is [more] involved,” he said.
Indeed, Dell’Oro VP Jeff Heyen told Fierce this method of extending DOCSIS 3.1’s lifespan can buy operators more time before they need to upgrade to an end-to-end DOCSIS 4.0 system. He reiterated that deploying CPE – that is, modems – “isn’t super labor intensive” either.
“You can get the speed burst at a minimal cost,” he said. “I mean the CPE is going to be expensive but they knew they were going to pay for that anyway so you might as well go ahead and get the speed benefit while you continue to go through the process of upgrading your outside plant.”
Though some operators in Europe have said they’re going to stop short of deploying DOCSIS 4.0, Jones noted “they are paying attention” to its interoperability work. He declined, however, to provide additional specifics about what this might mean for DOCSIS upgrades outside North America.
Security in focus
The next step, Jones added, will come at an August interoperability event where vendors will tackle implementing security features.
“Every press release talks about speed, but the team has upped the ante on security with 4.0,” Jones said. This includes implementing stronger encryption algorithms with ephemeral keys and enabling mutual authentication between the CMTS and modem rather than the single side verification used today.
The next interoperability event will be held by CableLabs the week of August 14.