Tài liệu Delivering Services over FTTP pdf

case studyDelivering Services over FTTP the Home Town Way Situation Home Town Cable Plus is an integrated service provider operating in the city of Port St.. Figure 1: PON Design for Ho

case study

Delivering Services over FTTP

the Home Town Way

Situation

Home Town Cable Plus is an integrated service provider operating in the city of Port St Lucie as well

as in the county of St Lucie in Florida Just three years ago, the new company embarked upon its plan to build a passive optical network (PON) to link homes and businesses in its service area to the company data center Home Town officially opened for business in September 2003 with a bundle that includes standard POTS as well as alarm and monitoring services In addition, Home Town offers

217 channels of SDV (switched digital video) and gigabit Ethernet high-speed Internet service over the advanced IP-based network

As Home Town management drew-up its business and operating plans, it was clear that offering highly competitive pricing and operating profitably was going to require long term cost containment In addi-tion, as a pioneer in delivering services over a fiber-to-the-premise network, it was also clear that Home Town’s PON architecture was unique It was going to require a different approach in the outside plant and more than off-the-shelf solutions to maintain reliable service levels and speed service turn-up

Figure 1: PON Design for Home Town Cable Plus

A Design Takes Shape

The Home Town network was conceived as a

two-fiber system—one fiber for voice and data

and one for video In addition, planners elected

to aggregate drop cables in fewer points in

neighborhoods, a design resulting in far fewer

above ground terminals that would appeal to

both builders and homeowners

The PON was designed around two major

com-ponents: Neighborhood Access Points (NAP) and

Local Conversion Points (LCP), each of which

feeds multiple NAPs, shown in Figure 1 LCP and

NAP cabinets would house splitters, splices and

distribution panels As with any PON, all active

equipment is centralized in the headend and

splitters deployed in the field so that PON cards

in the headend are purchased and activated in

unison with take rates, effectively deferring

capi-tal purchases closer to revenue

Referring to Figure 1, the design calls for fiber

feeder cable from the headend to be spliced

to rear input ports on splitters in the LCP

Distribution cables from NAPs are terminated

by splice on the rear of distribution panels in

the LCP This configuration allows cross

connect-ing between input side of splitters and output

side of distribution panels by use of simple

jumper cables

NAPs, which are deployed deeper in the network

and designed to support 32 or 64 homes, have a

similar design Distribution cable from the LCP is

spliced to rear input ports of splitters and at

service turn-up, drop cable is spliced to the

out-put side of a distribution panel Once fiber drop

cable is blown to the premise in pre-installed

conduit and spliced at the NAP, service

connec-tion in the field is completed with a fiber jumper

in the cross connect

The design for the outside plant was future

thinking With splitters in the PON rather than

centralized in the headend, the company was

able to reduce fiber count and construction costs

Upfront costs were also reduced by use of guide

tubes and blown fiber for drop cables By

invest-ing an additional 1% to 2% of total project costs

in a cross-connect architecture for the PON,

Home Town expects to generate long-term

oper-ational savings by reducing the time required for activation and troubleshooting This small invest-ment reduces capital investinvest-ment by full utilization

of PON card ports in the headend, which would not be possible with an all-spliced PON With a design in hand, the task turned to finding a ven-dor to supply LCPs and NAPs

PON Products Engineered Specifically for Home Town

Bill Flanagan, Director of Operations for Home Town Cable Plus, has worked on fiber projects for over 20 years before joining the start-up Home Town From initial investigations, it was evident there were no products existing from any vendor

to meet Home Town’s needs Yet he knew from first-hand experience of ADC’s track record for innovation and service both in the headend and the outside plant When it came time to find products for the PON, he invited ADC to the table After listening and discussing objectives with Home Town, ADC offered solutions for both LCPs and NAPs that combined components from existing ADC product lines The proposal called for ACE100, ACE200 and ADCE400 outside plant cabinets retrofitted with VAM (Value-Added Modules) splitter modules as well as dis-tribution panels, splice wheels, and cable stor-age modules from the OMX™line of optical dis-tribution frames

In all, ADC designed five different cabinets for Home Town—all from existing products ADC’s ability to come up with just the right cabinets for Home Town’s requirements was due to inherently modular product lines, savvy engineering support and, most important, highly flexible manufactur-ing processes As a vertically integrated manufac-turer and provider of mass-customized products for the past 60 years, ADC was able to tailor products to Home Town’s needs

“We had several companies out to visit with us and they all had good products But the others couldn’t produce exactly what we wanted ADC’s manufacturing expertise impressed us enough to know they could successfully combine several off-the-shelf products into a solution for us,” said Flanagan

ADC Telecommunications, Inc., P.O Box 1101, Minneapolis, Minnesota USA 55440-1101

Specifications published here are current as of the date of publication of this document Because we are continuously improving our products, ADC reserves the right to change specifications without prior notice At any time, you may verify product specifications by contacting our headquarters office in Minneapolis ADC Telecommunications, Inc views its patent portfolio as an important corporate asset and vigorously enforces its patents Products or features contained herein may be covered by one or more U.S or foreign patents An Equal Opportunity Employer

Web Site: www.adc.com

From North America, Call Toll Free: 1-800-366-3891 • Outside of North America: +1-952-938-8080 Fax: +1-952-917-3237 For a listing of ADC’s global sales office locations, please refer to our web site

Conquering Density with Proper Cable

Management

For ADC engineering, NAP design posed a dual

chal-lenge On one hand, Home Town wanted small above

ground cabinets in neighborhoods On the other,

cab-inets were going to be highly dense with either 32 or

64 two-fiber drops per NAP cabinet Adding to high

fiber count are splitters, splices and cross-connect

panels, all of which could converge into a potentially

unmanageable cabinet

In light of these challenges, making both NAPs and

LCPs technician-friendly and highly reliable meant

paying close attention to the details of cable

manage-ment Clamping, drop cable routing within the

cabi-net, cross-connect jumper management, fiber feeder

and distribution cable entrance and exit, splice

stor-age, bend radius protection, choice of connector—

these were all critical issues evaluated by ADC

engi-neers for Home Town

The solution started with standard ACE series outside

plant cabinets Designed to meet Telcordia GR487

and NEMA 4 specifications, the cabinets offer proven

durability and protection Engineers then found that

the highly modular components of the OMX optical

distribution frame system were well suited for the

project To manage splices, OMX splice wheels were

specified Each splice wheel provides not only splicing

but also ready storage for up to 3 meters of slack,

allowing technicians to move splice wheels away from

the cabinet to a proper position for effective splicing

Also brought into the solution were OMX storage

modules for secure storage of cross-connect jumpers

Finally, pre-terminated OMX distribution modules

ori-ented specifically for the right side of the cabinet,

along with VAM splitter modules, provided the ability

to cross connect in cabinets

Taken together, advanced cable management and

cross-connect functionality offered Home Town the

right features for operational efficiency and reliability

in the PON "Design of the cabinets addressed both

density and cable management issues," said

Flanagan "We will realize lower operating costs

because we’re going to take less time to activate, test

and troubleshoot," he said

Connectors in the PON Add Flexibility

Home Town expects to gain operational efficiency due

to use of cross-connects rather than all-splices for acti-vation and rearrangements in the PON Feeder and distribution cables are spliced behind distribution pan-els and, once spliced, are never touched again Service turn-up and other rearrangements are conducted by placing jumpers on the front of cross-connect panels rather than pulling fibers out, breaking splices, resplic-ing, and pushing fibers back into place—an operation that risks damage to adjacent fibers, too Given that fibers are inherently fragile, use of cross-connects in both LCPs and NAPs increases service life of fibers and minimizes risk of disruptions

The choice of connector style was an important con-sideration, too For the harsh environment of the out-side plant, Home Town chose ADC’s LX.5 small form factor connector From a fiber management perspec-tive, use of LX.5 supported Home Town’s two-fiber system because two LX.5 connectors are housed in the same space normally occupied by a single SC type connector

In addition, the integral shutter of the LX.5 connec-tor, which automatically closes when the connector is removed, protects ferrules from dirt and dust This simple feature ensures high fiber performance in an environment that is subject to contaminants

Combined with thorough bend radius protection within each cabinet, the quality and consistency of pre-terminated distribution panels ensure low signal attenuation when introducing connectors in the PON

Conclusion

From a capital and operating perspective, the overall network design works Use of cross-connects rather than splices in the PON allows Home Town Cable Plus

to maximize port usage on expensive PON cards while streamlining activation and troubleshooting As an early adopter of the PON architecture for FTTP, Home Town did not have the luxury to choose from a suite

of existing products Instead, Home Town relied on experience, flexibility and manufacturing prowess of ADC to help build the PON