RFoG and PON Markets Mature

One sign of a maturing market is news at the component level. That has been the case over the past few months for RF over Glass (RFoG).

Original equipment manufacturer TriAccess Technologies, for example, has released an amplifier designed for RFoG-based, fiber access networks. The integrated circuit uses what the company calls trans-impedance amplifier technology.

“With RFoG, you’re sending RF back upstream,” Brian Bauer, TriAccess VP marketing said in an interview earlier this year. One challenge is to “figure out the right balance between the laser transmitter and receiver at the headend. The receiver needs high sensitivity, low-low noise.”

Another original equipment manufacturing (OEM) development this year was the appearance at the Cable Show in April of chipset vendor Teknovus, which demonstrated a DOCSIS mediation layer (DML) technology.

Effectively a middleware, it enables system vendors to run DOCSIS OSSI service interfaces, PacketCable and PacketCable Multimedia on existing GigE (GE)PON and forthcoming 10G-EPON systems.

Others systems vendors have claimed progress in this arena. Alloptic announced the availability of a DOCSIS PON controller (DPC) in April. Aurora Networks also announced that it has similar control plane technology. Last year, Salira Systems (Hitachi) was the only vendor with this capability.

Differentiation

At the product and systems levels, this year also has new entrants. ARRIS moved into both RFoG and EPON markets. Electroline is a new RFoG player, and 4CableTV is also offering an RFoG extender node.

Drivers for FTTx may be deepening, especially on the business services front, which make the topic less academic.

“It’s moving from a case-by-case model to a ‘build-it-and-they-will-come,’ proactive model,” Bill Dawson, ARRIS VP Business Development said. “The SMB approach where you proactively build fiber to an area with a high density of business and you establish a short list of product offerings pretty much defines the opportunity that cable operators are trying to address right now.”

Differences between systems vendors also are sharpening, which is another sign of a maturing market. ARRIS, for instance, has added RFoG and PON to its CHP headend platform, a possible advantage given that Dawson estimates that some 1100-plus CHP shelves have been deployed already.

Aurora, on the other hand, is leveraging the outside plant and virtual (V) hub platform for its EPON technology. “Having an OLT (optical line terminal) in the field has several advantages,” John Dahlquist, Aurora VP Marketing said. “Most important is: it overcomes distance limitation.”

Other advantages Dahlquist listed include fiber friendliness of WDM, implementation of higher network availability via route redundancy, saving real estate at crowded indoor facilities.

DOCSIS challenges

Differences among RFoG approaches remain in part because although wavelength compatibility issues have been addressed, RFoG remains pre-standard.

“People are all over the map,” Mark Pallazzo, Cisco VP and GM Cisco Access Networks, said. In particular, he pointed to DOCSIS 3.0 upstream compatibility. “In the current RFoG thought process, unless you do something different in the reverse path, full four channel in the upstream is very problematic.”

Cisco has a “unique approach” involving upstream lasers to handle this challenge.

DOCSIS in general is a complicating factor, and a point of some confusion. While Cisco went with the D-PON nomenclature when it launched its Prisma-based RFoG (or ‘RFoG-plus’) platform a few years ago, Pallazzo admits that this is only Phase I.

“Phase II of that development actually looks more like that of an EPON deployment. But instead of using EPON, you’re using DOCSIS MAC layer as control plane for the PON technology,” he said.

Others have been eager to reach for the ‘D’ as well. Dawson said that the ARRIS EPON ONU “interfaces with the DOCSIS backoffice…as though it were a DOCSIS eMTA.”

Absent painstaking DOCSIS interops that have defined that spec, it may be difficult to verify such functionality. (For more on RFoG and PON, see additional coverage in the August issue of Communications Technology, or click here to attend today’s webcast, which also will be available in recorded format.)

—Jonathan Tombes