networkZONE Products for the week of November 17, 2003
Motorola Says . . .
Fiber-To-The-Whatever -- Motorola's Integrated Optical
LAYER Termination IC Reduces Cost Of Fiber-to-the-Premises CPE
Standards-Compliant Broadband Passive Optical Network (BPON)
Device Works with PowerQUICC Processors to Help Reduce Cost and Complexity
of Optical Network Termination Equipment
The promise of fiber to the premises (FTTx) is gaining momentum with the arrival of standards-based broadband passive optical network (BPON) solutions. Motorola, Inc. is addressing this growing market by introducing an industry-standard BPON chipset solution aimed at optical network termination (ONT) applications.
Broadband passive optical networking is designed to enable more than a 10x increase in bandwidth over existing broadband technologies, such as digital subscriber line (DSL) and broadband cable. Telecommunication carriers can leverage the higher bandwidth of BPON technology (up to 622Mbps downstream) to increase their revenue streams by offering subscribers "triple play" services of voice-video-data, and they can reduce their cost of deployment through point to multi-point architectures.
A key component of Motorola's BPON solution is the new MC92701, a BPON layer termination device that fully complies with the ITU-T G.983 specification. Adherence to this industry standard enhances PON system interoperability, which in turn can make it easier to build and deploy FTTx networks. The MC92701 works in tandem with Motorola's PowerQUICC I and PowerQUICC II communications processors to provide a comprehensive system solution for ONT equipment used in FTTx systems. The MC92701 device has been designed to interoperate with PowerQUICC processors, which are widely used to handle communications and control functions in both optical line termination (OLT) and ONT systems.
"Optical network equipment manufacturers are looking for off-the-shelf PON solutions to reduce system-level cost, and we're addressing their needs by delivering BPON chipsets that enable cost-effective, standards-based solutions," said David Perkins, corporate vice president and general manager of Motorola's Networking and Computing Systems Group. "Motorola's BPON solution expands the capabilities of PowerQUICC processors in ONT applications, enabling equipment manufacturers to accelerate the design, development and deployment of PON equipment."
"The PON market shows great potential with a large and growing installed base in Japan and proposed builds in the U.S. by leading RBOCs," said Allan Armstrong, program director for Global Communications Semiconductors at RHK. "With the introduction of its BPON solution, Motorola is one of the few semiconductor suppliers focused on this opportunity. The pervasiveness of cost-effective, standards-based PON interface components will be a key success factor for mass-market deployment of PONs in the second half of this decade."
FTTx deployments and trials are on the upsurge worldwide. According to Japan's Ministry of Public Management, Home Affairs, Posts and Telecommunications, there are more than 680,000 FTTx subscribers in Japan, and more than 80,000 new subscribers are being added each month. FTTx deployment is also expected to increase in other areas of Asia and Europe in the coming years. According to RHK, carriers are beginning to invest in FTTx network infrastructure, and greenfield PON deployments are expected to accelerate in 2004 and 2005, with mass-market penetration beginning to ramp in late 2005.
About the MC92701 BPON Layer Termination Device
The MC92701 is an ITU-T G.983 compliant BPON layer termination device that
supports dynamic bandwidth assignment (DBA). DBA is an innovative capability
for enhancing quality of service (QoS) in fiber-based broadband services
and for enabling additional services that require bandwidth peaks beyond
traditional fixed-bandwidth allocations.
The MC92701 also offers integrated clock and data recovery (CDR). Integration of CDR logic provides system developers with the flexibility to use lower cost 2R triplexer optical modules. The MC92701 leverages Motorola's broad asynchronous transfer mode (ATM) cell processing and mixed-signal expertise, integrating system timing and clock data recovery on-chip to reduce bill of material and optical module costs.
Key features and functions of the MC92701 device include:
analogZONE Says . . .
If the current economic recovery is going to be more than a short blip, it's going to need several long-term, high-value market drivers such as the RFP for Broadband Passive Optical Network (BPON) equipment issued by the big RBOCs this past spring. It seems that the big gorillas on the block are finally mustering their resources to answer the competitive threat posed by the cable companies with a comprehensive plan to roll out optical networks that can deliver voice, video and data in a flexible, cost-effective manner (See Fig. 1 for a block diagram of a typical BPON network).
Motorola knows that a big part of what's going to make or break this initiative will be driving the cost-per-subscriber of bringing fiber to the home, curb, (mailbox, dog house, or wherever) down to a level which can be amortized some time before Hades freezes over. They're doing their part to drive down the cost of the subscriber side of the network with the MC92701 -- BPON Layer termination device. Intended as the bridge between the optical and electrical networks, it's designed to cut the cost of Optical Network Termination (ONT) units -- i.e. the box on home side of the network.
The guts of a basic ONT include the optical module that does the basic O/E conversion, a PON layer termination device that takes the raw signal and turns it into packets, or cells, and a communication controller that does the actual traffic processing and routing (See Fig. 2). Motorola's strategy to cut the cost of the ONT is to absorb as many functions as possible from the optical module where they have been traditionally implemented in a more discrete manner. As we'll see it also gets its arms around most of the analog functions related to the management of the optical network -- as well as much of the digital logic that bridges between the BPON's native ATM traffic and the IP-based user environment. By integrating these functions into a single chip, designers can use a simpler, less expensive optical module on the front end, and virtually eliminate most components except for a generic communication processor from the back end of the ONT.
On the optical side of the network, the MC92701 performs the clock and data recovery on the 155/622 Mbit/s downstream signal coming in from the optical module (See Fig. 3). They've leveraged their experience with GBIC, SFP, and XFP modules to provide the electronics that work with lower-cost "2R" (as opposed to 3R -- recovery, retiming, regeneration -- 2R does not do retiming) optical modules that rely on external CDR.
The optical/analog side of the chip also contains the PON PHY layer -- a bundle of analog and digital circuits that handles all the tricky interactions between the laid down in the G983.2 ONT Management and Control Interface (OMCI) specification. Among other things it can be commanded by the CO-side equipment to adjust link speeds and to perform the and "ranging" function that allows the Optical Line Termination (OLT) unit at the CO to calculate the distance to any customer-side unit in the network. This is important so the system can be tuned and trimmed up to enable the use of the Dynamic Bandwidth Adjustment (DBA) protocol, a control scheme that works a lot like the cable industry's DOCSIS standard, to efficiently share a limited amount of bandwidth between dozens, or hundreds of users. The PHY also monitors the connection and provides alarms for LoS and transmission fault conditions.
Before the data hits the customer side and delivers the bits to their destination, it's passed through the MC92071's ATM transmission convergence layer logic and to a UTOPIA interface. While some (usually in Asia) BPONs do support native IP, the US RBOCs decided to use an ATM format to make it easy to support over large installed equipment base that's mainly ATM or TDM. The cells exit the UTOPIA interface and, if Motorola has its way, enter a PowerQUICC-based processor that converts cells to packets, routes traffic, and performs traffic management. Your choice of communication processor can range from a simple MPC 8XX to a powerful PowerQUICC II, depending on whether you're simply extracting IP for an Internet connection, or doing something more sophisticated like IP telephony or streaming video delivery.
The complexity and thoughtful functions integrated into the MC92071 seem to indicate that Motorola's heavily committed to this market. Another sign that Mot is betting the farm on this one is its serious involvement with assuring interoperability between CPE and CO equipment makers. While there is currently no 3rd Party interoperability testing between OLTs and ONTs available, they are working with both outside service and equipment providers to develop procedures and facilities to do this.
The more I learn about PONs the more nervous I get. While the technology is a promising trade-off between absolute performance and reasonable cost, I have many of the same reservations that I had about early cable modem systems. Most of them revolve around the problems associated with getting good performance out of a shared-media network -- especially when it's heavily-loaded. While I think PONs will eventually deliver on their promise, I suspect we're going to see several spins of the G983 standard and the equipment that supports it before we're on our way to a broadband Utopia. Fortunately, folks like Motorola will be working alongside the equipment vendors and network operators to ease the bumps along the way.
Motorola is currently sampling the MC92701 with production scheduled for Q1 2004. Separate pricing for the MC92701 is not available at this time. Pricing for the two-chip solution (MC92701 + PowerQUICC I or II processor) will range from $30 to $65, depending on volume, and which PowerQUICC device is selected.
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