Last week’s Cable Next Gen Event hosted by Light Reading in Denver was one of the best I have attended. Key stakeholders from several of the top 5 US Cable MSOs and international operator Liberty Global were on hand, and many provided valuable insights into the Cable Industry’s plans for gigabit services for the home and business. I served as a panelist on a panel entitled “Playing with PON: What’s Next for DOCSIS”, which featured John Dickinson of BrightHouse Networks, Robert Howald of Comcast, Joe Jensen of Block Communications, Joel Futterman of Iphotonix, and Shane Eleniak of Calix. The purpose of the panel was to discuss the tradeoffs between FTTH and DOCSIS and learn the challenges with implementing fiber-based access networks from the top domestic MSOs. In this post, I offer three key takeaways from our discussion last week and am happy to report that faster speeds are coming to a cable household near you.
Takeaway 1: Fiber is the Winner for the Greenfield
While much of the buzz around net-gen cable access initiatives is around upcoming DOCSIS 3.1 deployments, it was generally accepted on our panel that fiber is the best physical media to install in greenfield deployments. Fiber optics offer terabits of capacity with today’s technology and allow for separate high-speed residential and business networks to coexist on the same physical cable. John Dickinson, Vice President, Network Strategy and Architecture for Bright House Networks pointed out that 10 gigabit PON is available today and PON technology is expected to reach 25 gigabits per wavelength and upwards of 100 gigabits per PON in the near future. Many of the top cable MSOs prefer EPON to GPON technology citing interoperability among OLT and ONU vendors among the major reasons for their preference. With the above in mind, one semi-guaranteed way to enjoy blazing-fast fiber-based Internet access is to move to a new subdivision or MDU.
Takeaway 2: DOCSIS and HFC Technology are Here to Stay in the Brownfield
The nation’s top MSOs remain invested in their current HFC / Coax infrastructure in existing neighborhoods and MDUs. Upcoming DOCSIS 3.1 technology due out this year promises to increase the spectral efficiency in both directions on existing coax cable and allow for more spectrum to be bonded to create larger shared bandwidth. While existing DOCSIS 3.0 technology bonds channels 6MHz wide in the downstream, DOCSIS 3.1 removes the 6MHz incremental limit and allows for bonding of up to 192MHz wide channels to obtain a bandwidth pool of 1.8Gbps. If a complete 1GHz coax spectrum is available for data services and the upstream / downstream split is set at approximately 100MHz, it is possible to create a connection capable of 10Gbps downstream and 1Gbps upstream.
In addition to rolling out DOCSIS 3.1 en masse, Rob Howald of Comcast shared that his company is steering its plant upgrades to attain the goal of lower counts of subscribers per node and less amplifiers on each node. The net effect of this will mean more bandwidth shared among fewer subscribers and a higher speed available for each home.
Lastly, CableLabs recently shared its early findings on Full-Duplex DOCSIS which promises to eliminate the need for a split between forward and return path in the cable plant and offer symmetric, gigabit services. MSOs are tuned into the leading edge of this research but are careful to commit to timelines, testing, or deployments, as there are significant challenges in changing the plant’s attributes in this way.
3. Fiber Construction Costs are one of the main drawbacks to fiber everywhere
While most industry thought leaders agree that the overall performance of fiber optic cable is much better than coax or twisted pair, it remains costly to remove existing copper infrastructure and replace it with newer, faster fiber. Costs vary widely from $20 to up to $50 per meter of installed fiber in the outside plant. Factors influencing the cost include labor costs, rights of way, permitting and fees charged by local governments, equipment rental, and other costs associated with outdoor construction. In recent years, utility cables were buried in new construction instead of suspended from utility poles, which makes it more difficult to upgrade to fiber due to the need to dig. For this reason, many of the existing neighborhoods that are being upgraded to FTTH services are those with aerial plant.
To summarize, fiber offers terabits of bandwidth instead of gigabits provided by existing coax cable. FTTH technology such as 10-Gigabit EPON will be the next solution for the greenfield and in areas where competition and demand warrant it. While it’s difficult to say when all existing brownfield subdivisions will get fiber, cable MSOs remain committed to getting more life out of the existing coax and HFC plant. DOCSIS 3.1 and the emerging Full-Duplex DOCSIS offer the promise of gigabit services over this existing infrastructure. Lastly, fiber costs can be prohibitively expensive in many areas, especially the brownfield, and this is one key limiting factor to fiber everywhere. All things considered, 2016 holds significant promise for faster speeds and feeds for homes and businesses.