PONs operate throughout the world, mostly in Asia and
Europe. But usage is growing significantly in the U.S. Verizon
probably has the most subscribers, with just over 1 million
and with as many 18 million being projected for 2011. The
company's FiOS system is delivering IPTV to about a half-million customers. The rollout of this system is geared to Verizon's investment plans for broadband.
FiOS brings the fiber directly to the home.
Another major player is AT&T. Its Uverse IPTV and triple-play system is just
now being turned on in the U.S., with
many future networks being built.
AT&T's system brings fiber to the neighborhood DSLAM and delivers the final
signal via VDSL2 over the installed telephone twisted pair.
Other carriers are rolling out PONs,
too. Quest, another big carrier, sees fiber
not only as the future, but also as its salvation. Some experts estimate that over 50%
of PONs are really installed by those
rarely heard-of small local carriers. In any
case, PONs are on the rise and represent
the future of broadband. While cable TV
will hold the lead in broadband for the
time being, the telcos will continue to
catch up. Eventually, they could give cable
some real competition.
PON PRODUCTS
There's one way to tell that a segment
of industry is on the rise: Look at the number of new ICs
directed at that sector. A slew of new products is helping to
push the PON movement forward.
Leading the pack seems to be Broadlight, which has a chip
solution for almost every part of a PON system. On the carrier or OLT side, the BL3238 GPON OLT media-access-control (MAC) chip supports Ethernet packets and time-division-multiplexed (TDM) data over the GPON encapsulation
mode (GEM).
The standard downstream rate is 2.488
Gbits/s and either 1.244 Gbits/s or 622
Mbits/s upstream. The chip, which features configurable upstream and downstream FEC and AES encryption, supports up to 128 ONTs. Broadlight
PONmaker software speeds OLT
development.
One of Broadlight's newest products, the
BL3458 quad GPON optical line terminal controller ASIC, provides some of the industry's highest integration for packet and
TDM transport over GPON. It can dramatically reduce power, space, and costs
for multiport OLTs. At the heart of the
BL3458 lie four BL3238s.
Also integrated on chip are four serializer/deserializers
(SERDES) and burst mode CDRs. An embedded MIPS32
4KEc processor makes device provisioning and dynamic bandwidth allocation (DBA) easy. The PONjacket software simplifies OLT development and speeds time-to-market.
Broadlight's BL2347 is a GPON ONT chip that performs
bridging and modem functions and specifically targets cost
reduction. This system-on-a-chip (SoC) integrates a VoIP DSP
and a four-port Ethernet switch with 1-Gbit/s performance.
The GPON MAC fully complies with ITU-T G.984.
The BL2348 is a full GPON residential gateway ONT
on a chip (Fig. 2). It features dual PONRunner
network processors to handle the traffic, a
GPON MAC, and a MIPS 24k processor.
In addition, it has the four-port VoIP
switch and DSP. Also on chip are standard
interfaces for home-networking technologies such as 1 Gigabit Ethernet, 100-Mbit/s
Fast Ethernet, 802.11a/b/g/n, MoCA,
HomePNA and HomePlug, and USB.
The BL2348 gives you most of an ONT
and residential gateway in one chip, greatly
reducing size, cost, and power consumption.
The accompanying GateMaker software lets
you program gateway functions like firewall, security, SIP, management, quality of service (QoS), and NAT. Broadlight will
begin sampling at the end of 2007.
Conexant's PON SoCs target ONU
client products. The CX95292 XenonIIIG is for GPON systems and fully
complies with ITU-T G.984, while the
CX95203 Xenon-IIIE is for IEEE 802.3ah EPON (GE-PON). Both chips
have full 2.488-Gbit/s downstream and
1.25-Gbit/s upstream capability with
physical-layer encryption, security,
bridging, and routing to ensure QoS in
IPTV applications.
Also included are four concurrent
VoIP channels. Each brings enhanced
routing capabilities combined with deep
classification and filtering support to
enable the best QoS. Interfaces are additionally provided for Gigabit Ethernet,
MoCA, HomePlug, and HomePNA.
Cortina Systems has just introduced
its second-generation Ethernet PON
chip sets. The CS8021 is a highly integrated OLT on the central-office side of
the PON. It supports four EPON ports
in a single chip, so equipment manufacturers can build high-port-density chassis or stackable rack-mount systems. An
extensible SDRAM frame buffer facilitates QoS. On the CPE side, the CS8016
ONU is a single-chip solution with
embedded frame buffer memory, RAM,
and both PON and Ethernet SERDES. A built-in ARM9 processor is used for
management and control.
Network chip supplier PMC-Sierra
also recently made several PON
announcements. These are based on the
PON chip designs from Passave, which
PMC-Sierra recently acquired. Using the
company's GigaPASS architecture, the
PAS65311 GPON ONT reference design
includes a fully featured ITU-T G.984
GPON MAC, an advanced classification
engine, robust QoS queuing, advanced
VLAN bridging and manipulation, and
IPTV filtering, all performed at line-rate
speeds for all packet sizes.
The GigaPASS architecture integrates
multiple hardware-based, packet-processing engine subsystems to deliver
wire-speed packet processing at all
packet sizes. It combines them with a
control processor supporting Linux and
VxWorks operating systems and extensible middleware platforms. Available
now, the reference design features the
PAS6201-G0 and PAS6211 (Fig. 3).
Key to any PON system is the splitter/combiner. Ignis Photonyx AS's IXA70 line includes models in 1xN configurations with two, four, eight, 16, 32, and
64 lines that can be used to combine or
split the optical signals. Also, they're
made with silica-on-silica planar light-wave circuit technology. With low polarization dependent loss, they have an
insertion loss from 7 dB on the 1x2 unit
to 16.5 dB on the 1x32 device.