Introduction

Triple play services, with a prime focus on IPTV, continues to stimulate Fiber To The Home (FTTH) deployment.  Telcos hope to retain customers and realize incremental revenue by offering a variety of video services over the FTTH access network.  According to market-research firm IDC, fiber access will offer the best opportunity for the access equipment market, growing at 17% a year between 2004 and 2009. By 2009, the market for fiber access equipment will be worth $1.9 bn. These FTTH networks may become the carrier's extended network, where they provision and manage the home network access and services remotely. 

FTTH Market

Regional battle lines are now being drawn for FTTH schemes based on two passive optical network (PON) technologies: Ethernet PON (EPON) and Gigabit PON (GPON). EPON is now in volume deployment in Japan, while GPON is still at the earliest stages of adoption, with BPON being deployed now (e.g. Verizon's FIOS).

While U.S. telcos are focused on BPON and GPON for their FTTH deployments, several Asian countries are now deploying or considering EPON:

-Japanese carriers NTT, KDDI, and Softbank BB are currently deploying residential EPONs (they refer to EPON as “GEPON”) in production quantities. There are now over 5M FTTH installations in Japan (a mix of GEPON and point to point fiber access), with 30M installations projected by 2010 (u-Japan initiative).   "NTT is deploying 100,000 EPON [connections] a month," according to Michael Howard, principal analyst at Infonetics (see Table below). 

-FTTH is a 2008 priority for China, with 20M+ subscribers projected by 2010.  China Telecom is now conducting an EPON trial.

-Korea is targeted at 65% penetration -10M FTTH subscribers- at 100M b/sec by 2010.  EPONs are being trialled by several Korean telcos.

-Taiwan expects 4M FTTH installations by 2010.  ChungHwa Telecom (CHT) says they are committed in EPON deployment

Many Asia-Pacific carriers (including KT, China Telecom and China Network Communications) have yet to choose which PON technology to adopt. The stakes could not be higher for the PON equipment and component makers as they battle to secure up to 60 million potential PON users by 2010.  Please refer to the table below for market projections by region and technology.

PON Market in 2008
Regions	Number of PON Users
Asia-Pacific	16 million
North America	3.7 million
Europe	0.9 million
PON technology	Number of Users
EPON	10.4 million
GPON	7.3 million
BPON	2.8 million

PON Forecasts for 2008.    Source: INFONETICS RESEARCH

The crux of the GPON versus EPON debate is all about timing. While GPON has ITU-T backing and a bandwidth advantage over EPON, it is still in development. Any delay in time-to-market and the momentum shifts to EPON. EPON has volume and its proponents are addressing its perceived shortfalls.

NTT remains wedded to EPON. "We have achieved interoperability between the [EPON] system vendors," says Hiromichi Shinohara, director of NTT's access-network service systems labs. "NTT has no plans to introduce GPON systems to offer FTTH services, and will continue to deploy EPON."

 Source:  GPON vs EPON: the battle lines are drawn, Fibers.org 12/05

Is there sufficient EPON bandwidth?

Some pundits have argued that EPON doesn’t provide enough bandwidth per home.  Don’t believe that!  EPON delivers a total of 1G b/sec of usable bandwidth from the OLT to the passive splitter.  Even with a 1:32 split ratio (the 802.3ah standard only supports up to 1:16), each home based ONU would have 30M b/sec of downstream bandwidth.  That is sufficient for up to 3 HDTV channels (@ 8M b/sec) with 6M b/sec for Internet access, VoIP, or other application.  A more typical 1:20 split ratio would result in greater downstream and upstream bandwidth per ONU.

The new kid on the PON block

ImmenStar- a start-up company in Santa Clara, CA- hopes to accelerate the EPON movement.  The company has just announced a highly integrated EPON Switch chip set, which they claim packs more power and punch then their competitors (Passave/PMC-Sierra, Centillium, and Teknovus), which sell EPON Media Access Control (MAC) chips.  The combination of MAC switching/ Service Provider Bridging functionality with the EPON OLT or ONU functionality is a powerful combination.  It may give ImmenStar a competitive edge.

The MuLan™ Switch EPON chipset includes an IEEE 802.1D compliant Ethernet bridge/switch along with IEEE 802.3ah EPON functionality.  Its capabilities include: SLA based QOS, redundant management ports, 1:1 Automatic Protection Switching (APS) for fiber cut resiliency at the OLT.  The chip set supports 512 HDTV or 1K MPEG2 IPTV multicast channels.  The QOS functionality should enable carriers to guarantee the bandwidth dictated in service-level agreements, which is very valuable for video applications.  Traffic classification, shaping scheduling and buffer management are all supported along with wire speed Forward Error Correction (FEC) for both upstream and downstream transmissions.

The optical line terminal (OLT) chips have four ports, apparently the first EPON OLT chip to do so. This could lead to more densely packed OLTs for central offices. Having four ports also creates a built-in redundancy, as traffic can be shifted to a different port if something goes wrong.  The company claims they have the only EPON chip set that can be used to build a high density (24/48 port) OLT pizza box or line card solution.  This results in the lowest OLT and ONU cost structure, according to ImmenStar.

When I visited the company last week, I witnessed an impressive demonstration of high quality video –on- demand running in one window of a PC screen along with multicast video in another window.  A simulated fiber cut and APS was then demonstrated.  The images initially froze, but when the cable was reconnected the full motion videos resumed.  The company also demonstrated interoperability with prototypes that used their competitors chip sets (which do not include the switching functionality).

While ImmenStar’s current efforts are on gaining EPON design wins, they are also developing GPON chips in preparation for future telco deployments.