Cable Adopts EPON as Fiber Standard for Delivering Business Services

CableLabs signaled the move in mid-October, when it announced that it would soon release a new set of technical specifications for carrying Ethernet Passive Optical Network (EPON) services over fiber lines. The planned specs are intended to give cable operators a common way to use DOCSIS provisioning and back-office systems to support EPON-based fiber networks. Known as DOCSIS Provisioning of EPON (DPoE), the specs are designed mainly for commercial-class IP and Ethernet services. But industry analysts say they could also eventually be used to deliver residential services over fiber lines.

In a display of major cable support for the new industry specs, Comcast, Time Warner Cable, and Bright House Networks have enthusiastically endorsed the CableLabs move. With the strong support, cable industry experts expect DPoE to be a significant factor as cable operators seek to extend their Metro Ethernet services to midsize and large commercial customers.

Industry experts say the push to adopt EPON and marry it with DOCSIS for business services makes sense for several reasons. Speaking at a Light Reading conference in New York last month, they cited technical and economic reasons for choosing EPON as cable’s fiber standard, especially when compared with the rival Gigabit Passive Optical Network (GPON) standard favored by most telcos.

For one thing, EPON, an IEEE standard, is “nicely priced,” said Doug Jones, the vice president of access technologies at Comcast. He said EPON gear is already available from multiple equipment suppliers, as cable operators figure out how to apply DOCSIS-based order entry and management tools to the technology. “The economics of EPON and GPON are about the same,” he said.

Jones said EPON is symmetric, unlike GPON. And EPON seems to be on a quicker upgrade path to symmetric 10 Gbps speeds, while a similar next-generation version of GPON is still likely two years away, he said. Jones also likes EPON’s upgrade path, noting that cable operators will be able to swap in 10-Gig cards and turn on services without switching out their customer-facing EPON gear. “Upgrading to 10-Gig is as seamless as it can be,” he said.

What’s more, Jones said, DPoE “spoofs” the DOCSIS back-office, so cable operators won’t have to learn a new provisioning system and train people to operate it. “Why reinvent the wheel?” he said. Jones said cable operators also like that EPON equipment offers them a wide range of interoperable gear for their budding FTTP networks. As a result, he said, operators can keep buying off-the-shelf equipment and preserve their DOCSIS back-office investments.

The cable industry will soon start testing that hypothesis. Jones said CableLabs’ first DPoE interoperability event will take place in the third week of January. Additional interops are scheduled each of the next three quarters of the year.

Jones said CableLabs is also working on a “Phase II” DPoE platform that will add support for more advanced Ethernet services, such as E-Line and ELAN. He expects that set of specs to be completed in time for the 2011 Society of Cable Telecom Engineers (SCTE) Cable-Tec Expo in November in Atlanta.

Jones said Comcast is testing EPON and DPoE in the lab. He estimated that Comcast could begin deploying the fiber technology “in a few markets” starting in 2011. He declined to specify the markets or the timing.

The cable industry’s embrace of EPON technology for fiber networks comes at the same time that the SCTE is seeking to wrap up its new Radio Frequency over Glass technical standard, which would let cable operators run fiber extensions off their current HFC plant, without changing their equipment and systems. Although RFoG doesn’t inherently support any PON technologies, a number of major cable equipment suppliers, including Arris, Cisco, Hitachi and Motorola, have developed PON-enabled extensions of their RFoG gear.