Cisco Says CCAP's Tipping Point Is 1Gbit/s
That was one of the conclusions presented by Cisco Senior Director of Marketing John Mattson on Wednesday during a Light Reading webinar on cable's CCAP activities (an archived version will soon be available ).
To achieve shared 1Gbit/s downstream using today's Docsis 3.0 technology, an operator would need to bond 24 channels. Modems based on the new Intel Corp. (Nasdaq: INTC) Puma 6 chipset can do that, but most D3 modems being deployed now can bond eight downstream channels -- enough for about 300 Mbit/s. Vendors of cable modem termination systems (CMTSs), meanwhile, are already working on software that can bond 32 downstream channels. Docsis 3.1, a spec under development at CableLabs , anticipates downstreams of up to 10 Gbit/s and a 1Gbit/s upstream. (See Intel's New Docsis 3.0 Chip Guns for 1-Gig , Cable Access Goes for Bigger Broadband, More Docsis 3.0 Gateways Gun for 1-Gig and Docsis 3.1 Targets 10-Gig Downstream.)
All of that work is setting the stage for cable operators to expand CMTS capacities and deploy high-density edge QAMs before swapping for a new class of CCAP that combines those functions. That means operators will get a chance to test and deploy all of the operational changes that will be necessary with CCAP, which, for the first time, will converge cable's Docsis and video traffic onto one platform.
Every vendor in the CCAP game is developing products to facilitate this sort of migration. In Cisco's case, it has introduced a faster routing engine and a higher-density downstream card that can be plugged into its flagship CMTS, the uBR10000. The new downstream card essentially doubles the CMTS's Docsis downstream density, while the routing piece quadruples the CMTS's processing capacity, to 40Gbit/s. The new CMTS cards will be out in the first quarter of 2013, in time for some expected trials with cable operators in the U.S. and abroad. (See Cisco Extends Bridge to CCAP .)
Cisco insists that this interim step, combined with company's high-density, chassis-class RF Gateway-10 edge QAM, will help cable operators get close to the densities specified by CCAP, giving them some runway before making the big switch.
Cisco happens to have a CCAP chassis in development -- something it calls the Converged Broadband Router, or cBR-8. Mattson said Cisco expects to have that ready to go by early 2014, noting that it will help cable operators scale up for the capacities they'll need for 2018 and beyond.
"You don't want to deploy a box like this if you're not loading it up significantly," Mattson warned, noting that operators could end up paying a higher cost per bit if they try to install a full CCAP before their capacity needs require it. While service group sizes vary by operator, Mattson noted that a 1Gbit/s Docsis deployment would typically provide about 7.2Mbit/s of bandwidth per subscriber.
Fellow panelist Jorge Salinger, the vice president of access architecture at Comcast Corp. (Nasdaq: CMCSA, CMCSK), offered an update on his company's deployment plans for 2013 and beyond and shared some results from the MSO's six-month CCAP operational-readiness conducted earlier this year. Light Reading Cable will detail some of those activities in a follow-up story.
— Jeff Baumgartner, Site Editor, Light Reading Cable