FTTH Tutorial 8-7-03

Fiber-to-the-HomeOverview & Technical Tutorial

Jim Farmer, Vice PresidentLeonard Ray, Government Relations Committee Chairman

Fiber-to-the-Home Council

FTTH Council FTTH Tutorial (8/07/03)2

Fiber-to-the-Home (FTTH)Overview and technical tutorial

• The FTTH Council

• FTTH market overview

• FTTH technical tutorial

• Standards update

• Questions


The FTTH CouncilVisit us on the web at www.ftthcouncil.org

• Mission:– Educate, promote & accelerate FTTH and the resulting quality-of-

life enhancements

• Objectives:– Supply a consistent and accurate view of FTTH– Promote FTTH market development– Be recognized by the industry as the FTTH resource

• 78 member companies, organizations and individuals

• We represent the interests of those interested in FTTH– Our members are from every telecommunications group– We do not represent any one group


The FTTH Council Represented in every layer of the FTTH value chain

Retail provider

Wholesale provider

Network owner

Network construction

Content aggregator

Content provider

OEM Feasibility consultants

ROW owner

Financial consultants

Network design

Project management

Fundingsource

Our members include service providers (RBOCS, CLECs, Municipalities, and Rural LECs), network design and construction companies, financial consultants, and equipment manufacturers.







• Questions


FTTH overviewList of ‘US Optical Fiber Communities’*

AlabamaSylacaugaCaliforniaAmerige HeightsCanyon HillsKenwoodParc MetropolitanPalo AltoPoppy Measdoss

* many more in construction and pre-construction

RosevilleSacramento TalaveraColoradoBuckhorn Valley Colorado CityEagle RanchRyeFloridaLPGA Community

KansasAlmenaHill CityNortonOsborneQuinterSharonWakeeneyWamegoMassachusettsPine HilsTautonMichiganCobblestoneMinnesotaAlbertaChokioEast OttertailEvermoorMorrisNebraskaBlair

OklahomaHinton OregonWoodburnPennsylvaniaKutztownSouth CarolinaDaniel IslandSandy PointTexasBurlesonLaredoCanyon Gate BrazosLakes on EldridgeNorthpointeRock CreekGrand Lake EstatesVictory LakesCrystal FallsUtahKamasProvo

GeorgiaDunwoodyIowaCambridgeGuthrie CenterHuxleySlaterIdahoBear Creek

VirginiaAshburnBrambletonBraemar-BristowBristolLeesburgPurcellvilleWashingtonChelan CountyDouglas CountyGrant CountyIssaquah HighlandsMason County


FTTH overviewFTTH homes passed in US and Canada

Source: Render, Vanderslice& Associates

19,400

72,100

315,000

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

2001 2002 2003e

Greenfield29%

Overbuild71%

2002 FTTH networks

110,000 as of March, 2003


FTTH overview FTTH homes connected in US and Canada

FTTH Homes Connected(United States and Canada)

10,350

22,500

38,000

5,500

0

5,000

10,000

15,000

20,000

25,000

30,000

35,000

40,000

Sep 01 Mar 02 Sep 02 Mar 03

Source: Render, Vanderslice & Associates







• Questions


FTTH technical tutorialWhat is FTTH?

Copper

Fiber

24 kbps - 1.5 MbpsOld networks, optimized for voice

CO/HE

19 Mbps - 1 Gbps +Optical networks, optimized for voice, video and data

CO/HE//

CO/HE//

//

Note: network may be aerial or underground



• “An OAN in which the ONU is on or within the customer’s premise. Although the first installed capacity of a FTTH network varies, the upgrade capacity of a FTTH network exceeds all other transmission media.”– OAN: Optical Access Network– ONU: Optical Network Unit– OLT: Optical Line Termination

CO/HE//

ONUOLT

Source: www.ftthcouncil.org

OAN



CO/HE

Optical fiber and lasers

Architecture (Electronics)- PON?- Active node?- Hybrid?

Transport- ATM?- Ethernet?

Philosophy- Retail- Wholesale

Technical considerations

//


FTTH technical tutorialWhy FTTH?

• Enormous information carrying capacity

• Easily upgradeable

• Ease of installation

• Allows fully symmetric services• Reduced operations and maintenance costs • Benefits of optical fiber:

– Very long distances– Strong, flexible, and reliable– Allows small diameter and light weight cables– Secure – Immune to electromagnetic interference (EMI)


FTTH technical tutorialWhy FTTH? - more capacity*

* Typical system capability for 100 m link

0

50

100

150

200

Gb

ps

Twisted Pair Co-ax Multimode Single-mode

Source: Corning Incorporated


0

10

20

30

40

50

60

70

80

90

100

kilo

mete

rs

Twisted Pair Co-axial Multimode Single-mode

FTTH technical tutorialWhy FTTH? - longer distances*

* Typical distance for 1 Gbps system capabilitySource: Corning Incorporated


FTTH technical tutorialWhy FTTH? - symmetric services

Source: Grant County Public Utility District

• Outbound Internet bursting to 80Mbps

• Inbound Internet (download) averaging about 35-40Mbps

• Upstream is consistently twice the download


FTTH technical tutorialWhy FTTH? - fiber versus copper

• A single copper pair is capableof carrying 6 phone calls

• A single fiber pair is capable ofcarrying over 2.5 millionsimultaneous phone calls(64 channels at 2.5 Gb/s)

• A fiber optic cable with the sameinformation-carrying capacity (bandwidth) as a comparable copper cable is less than 1% of both the size and weight

• A single copper pair is capableof carrying 6 phone calls

• A single fiber pair is capable ofcarrying over 2.5 millionsimultaneous phone calls(64 channels at 2.5 Gb/s)

• A fiber optic cable with the sameinformation-carrying capacity (bandwidth) as a comparable copper cable is less than 1% of both the size and weight



FTTH technical tutorialWhy FTTH? - fiber versus copper

Glass• Uses light• Transparent• Dielectric material-nonconductive

– EMI immune• Low thermal expansion• Brittle, rigid material• Chemically stable

Copper• Uses electricity• Opaque• Electrically conductive material

– Susceptible to EMI• High thermal expansion• Ductile material• Subject to corrosion and galvanic

reactions• Fortunately, its recyclable

//


• Core– Carries the light signals– Silica and a dopant

• Cladding– Keeps the light in the core– Pure Silica

• Coating– Protects the glass– Acrylate (plastic)

• Core– Carries the light signals– Silica and a dopant

• Cladding– Keeps the light in the core– Pure Silica

• Coating– Protects the glass– Acrylate (plastic)

FTTH technical tutorialHow do optical fibers work?

Len Ray

CORE

CLADDING

COATING

245 μm 125 μm 8 - 62.5 μm



FTTH technical tutorialHow do optical fibers work?

• Optical fibers work on the principle of total internal reflection

• Light waves (“modes”) are reflected and guided down the length of an optical fiber


CORE

CLADDING


FTTH technical tutorialTypes of lasers used

• There are two laser technologies that are used for nearly all single mode communications applications– Fabry-Perot (F-P) lasers

• Lower in cost, lower in power• Poorer wavelength stability

– Distributed Feedback (DFB) lasers• Higher cost, higher power• Excellent wavelength stability• Excellent temperature stability

– Internally modulated• Good for moderate powers and distances

– Externally modulated• Ultimate today for quality in broadcast applications

• Vertical Cavity Surface Emitting Lasers (VCSELs)– Coming technology, promises lowest costs


FTTH technical tutorialTypes of lasers used

• Wavelengths used for Single Mode Fiber (long distances) communications– 1310 nm

• Usually lowest cost lasers• Used for shorter broadcast runs and short to moderate data runs

– 1550 nm• Can be amplified with relatively low-cost erbium doped fiber amplifiers

(EDFAs)• Lasers are fabricated on a number of different wavelengths (about 1535 –

1600 nm) for wave division multiplexing (WDM) applications• Slightly lower fiber loss at 1550 nm

– 1490 nm• Increasingly popular for downstream data in 3 systems.

– Cannot be amplified as easily– Somewhat higher device cost


FTTH technical tutorialSingle and Dual Fiber Systems

• Single Fiber– Downstream broadcast* on 1550 nm– Upstream data on 1310 nm– Downstream data on either 1310 or 1490 nm* depending on

system– Advantages

• Less fiber deployed• Fewer optical passives (taps or splitters)• Fewer labor-intensive connections

* Downstream data can be carried at 1550 nm if not used for broadcast


FTTH technical tutorialSingle and Dual Fiber Systems

• Dual Fiber– Various plans, usually one fiber will be used for downstream and

one for upstream, or one will be used for broadcast and one for data. Sometimes one will be used for specialized services, such as returning RF-modulated data from set top terminals

• Advantages– Simplifies terminal passive components– Somewhat lower signal loss



CO/HE





//



FTTH technical tutorialTransport - ATM

Destination header

53 byte cell

Data Next cell5B


• ATM has its roots in the telephone business• Connection-oriented protocol with excellent QOS• When a connection is made, it exists for the entire

communication session, ensuring a reliable channel

Ted Alice

JimKathy

Jeannie Travis

Susan Kyle

Joy Craig

FTTH technical tutorialTransport - ATM


FTTH technical tutorialTransport - Ethernet

Pre

amb

le

& S

FD

Des

tin

atio

n

add

ress

So

urc

e

add

ress Data and pad

Fra

me

chec

k

Typ

e/le

ng

th

Idle until the

next cell arrives8 4

Packet of data

6 6 2 up to ~1500 bytes


• Ethernet has its roots in office data systems• Connectionless-oriented, with excellent efficiency• Packets are transmitted individually, requiring resources only

when they are being transmitted

Ted Alice

JimKathy

Jeannie Travis

Susan Kyle

Joy Craig

Opportunistic data moves during idle times

Opportunistic data

When data is available, it gets the first available chance to be sent.

Nothing to send

FTTH technical tutorialTransport - Ethernet



CO/HE

Architecture(Electronics)- PON?- Active node?- Hybrid?




//



FTTH technical tutorialArchitectures

• Passive Optical Networks (PONs)– Shares fiber optic strands for a portion of the networks distribution– Uses optical splitters to separate and aggregate the signal– Power required only at the ends

• Active Node– Subscribers have a dedicated fiber optic strand

– Many use active (powered) nodes to manage signal distribution

• Hybrid PONs– Literal combination of an Active and a PON architecture


FTTH technical tutorialArchitectures – PON (A-. E- or G-)

//

//

//

//

//

////

//ONU

OLT

Optical splitter

1x16 (1x2, 1x8)

1x32 (1x4, 1x8)

Usually 10-20 km


FTTH technical tutorialArchitectures – PON (2) (A-. E- or G-)

//

//

//

//

//

////

//

1550 nm broadcast (if used)

1490* nm data

1310 nm data

* Data may be transmitted at 1550 nm if not used for video

ONU

OLT


FTTH technical tutorialArchitectures – Active Node

//

//

//

//

////

//ONU

Processing (powered)

Up to 70 km Up to 10 km

OLT


FTTH technical tutorialArchitectures – Active Node (2)

//

//

//

//

////

//

1550 nm broadcast (if used)

Data, 1310 or 1550 nm (depending on

distance) on separate fibers

OLT

ONU


FTTH technical tutorialArchitectures – Hybrid PON

//

//

//

//

////

//ONU

OLT

Processing (powered)

Up to 70 km

//

//

Up to 10 km

Optical splitter

Optical splitter


FTTH technical tutorialArchitectures – Hybrid PON (2)

//

//

//

//

////

//

//

//

1550 nm broadcast

Data, 1310 or 1550 nm (depending on distance)

on separate fibers

Single fiber, 1550 broadcast, 1310 bidirectional data

OLT

ONU



CO/HE

Architecture(Electronics)- PON?- Active node?- Hybrid?






FTTH technical tutorialPhilosophy

• Two types of FTTH networks exist today– Retail

• Vast majority of FTTH builds today• Network owner sells services directly to subscribers• Follows traditional telecommunications and cable television

models

– Wholesale• Market created by a few state laws• Network owner sells capacity to multiple providers who in turn

sells services to subscribers• Only examples in US today are some municipal FTTH networks



CO/HE






//


FTTH technical tutorialTechnical considerations

• Data– How much per home?– How well can you share the channel?– Security – how do you protect the subscriber’s data?– What kind of QoS parameters do you specify?– Compatible business services?

• SLAs• T1

• Support for voice?• Support for video?

– Broadcast– IPTV



• Data– How much per home?– How well can you share the channel?– Security – how do you protect the subscriber’s data?– What kind of QoS parameters do you specify?


FTTH technical tutorialTechnical considerations - Speed

• Data requirements– Competition: ADSL, cable modem ~0.5 to ~1.5 Mb/s shared,

asymmetrical– FTTH ~10 to 30 Mb/s non-shared or several 100 Mb/s shared,

symmetrical– SDTV video takes 2-4 Mb/s today at IP level– HDTV takes maybe 5 times STDV requirement– Pictures can run 1 MB compressed– 5.1 channel streaming audio would run ~380 kb/s


FTTH technical tutorialTechnical considerations - Speed

Service

Required Data Rate

VoIP

Streaming audio

Picture in 15 seconds SDTV

HDTV

FTTH

DSL or cable modem


Technology Minutes Hours Days

Modem 56 kb/s

2

ISDN 128 kb/s

20

12

DSL 1 Mb/s 2.5

Cable 2.5 Mb/s

1

45

FTTH 0.4

Estimated minimum time to acquire BraveheartAugust 17, 2001:MGM, Paramount Pictures, Sony Pictures, Warner Brothers, and Universal Studios unveiled plans for a joint venture that would allow computer users to download rental copies of feature films over the Internet.

December 9, 2002:“Hollywood's Latest Flop”

Fortune Magazine“The files are huge. At 952 Megabytes, Braveheart took just less than five hours to download using our DSL Line at home… in the same time we could have made 20 round trips to our neighborhood Blockbuster”

FTTH technical tutorialTechnical considerations – Speed (IPTV Reference)


• Security– Data is shared in the downstream direction in most systems– Your Gateway filters out all packets not intended for you– But there is fear that someone will snoop on your data– FSAN has a low-complexity, low-security encryption scheme– 802.3ah has formed a committee to study security– Manufacturers have taken their own tacks on security, from

none to robust



FTTH technical tutorialData Flow and Security - Downstream

//

//

//

//

////

//

Tom Dick

Harry

T D H

T D

HBox on side of home separates out only the data bound for that subscriber. But the fear is that someone will fool his box into giving data intended for another subscriber. Solution is to encrypt the data.

Time division multiplex (TDM) – each subscriber’s data gets its turn.


FTTH technical tutorialData Flow and Security - Upstream

//

//

//

//

////

//

Tom Dick

Harry

T D H

HDue to the physics of the network, Harry’s data flows upstream but does not come to Tom’s box, so Tom cannot see Harry’s data

Time division multiple access (TDMA) – similar to downstream, with gap for

laser start/stop


FTTH technical tutorialData Flow and QoS

//

//

//

//

////

//

Tom Dick

Harry

T D H

T D

H

If Dick has paid for more bandwidth, he gets more

If Tom’s packets need higher priority (e.g., telephone), they go first


FTTH technical tutorialTelephony Considerations

Depending on whether the FTTH system is based on ATM or Ethernet, the basis of the phone technology is either conventional switched circuit or the newer VoIP


FTTH technical tutorialConventional Switched-circuit Telephone

. . . . . .

During conversation, line is continually tied up in both directions To other class 4

and 5 switchesBob

Ted

Carol

Alice

Donald

Concentrator (DLC) Switch

Switched Circuit Telephony


FTTH technical tutorialExample VoIP System

To PSTNTelephone packets

Other data packets

During conversation, line is shared with other data packets on each side of the router

One Form of Voice on Internet Protocol (VoIP)

Customer Gateway

Customer Gateway

Media Gateway

Router (switch)

Customer Gateway

Customer Gateway

Customer Gateway

Bob

Ted

Carol

Alice

Donald

Data

Data

Data

Data

Data

Softswitch


FTTH technical tutorialVideo

Video is a popular service, which is a good basis for any new entrant FTTH provider. There is one way to provide video on cable and satellite (broadcast) and one way to provide video on DSL (IPTV). There are two ways to provide video on FTTH (broadcast and IPTV). The market place can sort out the use of each, to the benefit of the subscriber. We will describe the differences.


• Can send video several different ways on FTTH– Broadcast (cable TV standards)

• Analog• Digital• Cable TV good engineering practice is 47-48 dB C/N

– FTTH can achieve 48-51 dB C/N• Benefit from high volume and plethora of applications of cable boxes• RF return support for STTs

– IPTV – TV transmitted over Internet Protocol• Feasible, and some people are doing it in place of broadcast• Bandwidth hog, but statistics can work for you

– Interesting hybrid model awaits hybrid STTs, but can give the best of both worlds

FTTH technical tutorialTechnical considerations - Video


FTTH technical tutorialWays of transmitting video

Baseband analog video

Modulated analog video

Other channels

Digital compressed video...101101001...

Ch 2 55.25Ch 3 61.25

etc.

Analog optical

transmitter

OR

. . .Other

data sources

Digital optical network

Digital optical

transceiver

syncblack

white

MPEG-2 transport

stream

Broadcast optical network

Encoder

Analog RF modulator

Digital RF modulator

Place MPEG packets in IP packets

L2/L3 Switch


FTTH technical tutorialWays of transmitting video – wave division muxing

Analog (Broadcast)

optical transmitter

Digital optical

transceiver

Always 1550 nm

Several wavelength plans:1. 1310 nm bidirectional2. 1490 nm downstream,

1310 nm upstreamDigital optical

transceiver

Voice (typ POTS)

Data (typ 10/100Base-T), includes IPTV

Video to TVs and STTs

Analog optical

receiverRF

Diplexer

Headend, Central Office,OLT

Home terminal, NID, Gateway, ONT

Optical network

1550 nm

1310 and possibly 1490 nm

RF return from STTsWave

division multiplexer

(WDM)

Wave division

multiplexer (WDM)

AGC H

L

A/D & proc

Proc


FTTH technical tutorialWays of transmitting video – broadcast headend

. .

. Analog channels

Digital channels

To distribution plant

...

Frequency

Amplitude

Ch 2

Ch 3

Linear (broadcast, analog) optical transmitter

Earth station

Spectrum diagram:

Analog channels Digital

channels

IRD

Analog RF modulator,

stereo, scrambler

Analog RF modulator,

stereo, scrambler

Transcoder, digital RF

modulator, upconverter

Transcoder, digital RF

modulator, upconverter

RF return signals

VOD server

IRT

IRD


FTTH technical tutorialWays of transmitting video – broadcast subscriber

Analog (broadcast, linear) optical

receiver, one per endpoint

Set top terminal

Select channel by selecting frequency

Optics in

(Not required for analog-only service)

(opt. RF Return)

. .

.

Tuner Demod Descrambing Subscriber's TV


FTTH technical tutorialWays of transmitting video – IPTV headend

. . .

. . .

Analog channels

Digital channels

To groups of subscribers

Digital (binary) optical transceiver (part of router)

. . . . . .

Downstream data

H D H D

IRD

IRD

IRT

IRT

Encoder

Encoder

Transcoder

Transcoder

VOD server

Other data sources

Pac

ket-

s wi t

ched

net

wo

rk


FTTH technical tutorialWays of transmitting video – IPTV subscriber

Digital (binary) optical transceiver, one per

endpoint

FTTH interface

Other applications

IP Set top terminal

Select "channel" by requesting to join a multicast group, or requesting a stream from a VOD server

. . .

Optics in

Select data packets for subscriber

Packet request and selection

Decoding

H D H

In-home routing

Subscriber's TV


FTTH technical tutorialWays of transmitting video – IPTV unicast (VOD)

Router A(headend)

Router B

Router C(network)

Router D(NID)

Router E

Program request

Program stream

In-home routing

In-home routing

In-home routing

Subscriber's TVSet top terminal

In-home routing

VOD server


. .

.

Router A(headend)

Router B

Router C(network)

Router D(NID)

Router EProgram packets

1 multicast video program

Larry's STT and TV

Moe's STT and TV

Curley's TVSTT

In-home routing

In-home routing

In-home routing

In-home routing

Encoder

Transcoder

FTTH technical tutorialWays of transmitting video – IPTV unicast (VOD)


FTTH technical tutorialWays of transmitting video – IPTV multicast

. .

.

Router A(headend)

Router B

Router C(network)

Router D(NID)

Router E

?

?

?

?

Program packets

Program requests

1 video program

Larry's STT and TV

Moe's STT and TV

Curley's TVSTT

In-home routing

In-home routing

In-home routing

In-home routing

Encoder

Transcoder


FTTH technical tutorialWays of transmitting video – IPTV multicast

. .

.

Router A(headend)

Router B

Router C(network)

Router D(NID)

Router E

?

?

?

?

Program packets

Program requests

1 video program

Larry's STT and TV

Moe's STT and TV

Curley's TVSTT

In-home routing

In-home routing

In-home routing

In-home routing

Encoder

Transcoder


FTTH technical tutorialPON link budgets

A system is limited in the distance you can send signals and the maximum number of times you can split the signal to go to different subscribers. The main problem is usually that the signal level drops too low to be usable. Other considerations sometimes dominate.



//

Fiber loss per km is 0.25 dB (1550 nm) to 0.4 dB (1260 - 1360 nm)

//

Every time the signal is split two ways, half the power goes one way and half goes the other. So each direction gets half the power, or the signal is reduced by

10log(0.5)=3 dB.

Practical loss is 3.5 dB nominal, so every two-way split costs about 10 km distance @ 1310 nm

Half

Half



• Broadcast analog video often sets the budget– Maximum practical level without SBS issues ~16 dBm (long

spans)– Minimum receive level for 48 dB C/N ~-5 dBm

• Link budget is ~21 dB, a bit more if you are careful

– At 1550 nm, fiber exhibits loss of about 0.25 dB/km, so maximum distance without amplification is ~80 km• Requires good externally-modulated transmitters (available)

– Each two-way split results in a loss of nominally ~3.5 dB of level, assume 4 dB worst case.• Thus, each two-way split costs about 16 km distance


FTTH technical tutorialAnalog video link budgets

Split Nom. splitting loss (dB)

Avail. fiber loss (dB)

Nom. Distance

(km)

4 7 11 44

8 10.5 7.5 30

16 14 4 16

32 17.5 2.5 10

64 21 -1 -4

Notes: based on nominal fiber and splitter loss, not worst case. Practical distances are less. Includes 2 dB for connectorization loss, 1550 nm externally modulated transmitter


FTTH technical tutorialGigabit EPON link budgets (example, based on GBE best case)

Split Nom. splitting loss (dB)

Distance (km), 40 km

GBIC

Distance (km), 70 km

GBIC

4 7 14 44

8 10.5 4 34

16* 14 - 24

32 17.5 - 14

64 21 - 4

Notes: based on nominal fiber and splitter loss, not worst case. Includes 2 dB for connectorization loss, 1310 nm DFB laser

* EFM standard split ratio, 10 and 20 km optics







• Questions


FTTH technical tutorialStandards?

• Customers want to use standardized systems for maximum choice in equipment, lowest cost, and widespread availability

• There are two known groups working on standards– FSAN – Full Service Access Network

• Reports submitted to ITU as the standards body• Formed by 7 telecom companies in 1995• Now many more members• G.98x series of standards, most based on ATM but now adding others

– IEEE 802 EFM – Ethernet in the First Mile• First standards due out 2004• Fiber and copper Ethernet to the home and business


FTTH technical tutorial ITU-T G.98x series

• Only published international standard for FTTH

• Describes a Passive Optical Network carrying ATM traffic and TDMA subscriber access

• Several versions published since October 1998– G.983.1 - Basic ATM-PON system– G.983.2 - ONT management and control interface– G.983.3 - WDM system for enhanced services (i.e. analog

video)– G.984.1 and -.2 – GPON (hybrid ATM and Ethernet)– G.985 – 100 Mb/s point-to-point, Ethernet


FTTH technical tutorial IEEE 802.3ah - Ethernet in the First Mile (EFM)

• Organized informally via the IEEE 802.3 in Fall 2000

• Chartered as IEEE 802.3ah in Spring 2001

• Develop 1 Gb/s Ethernet access standards including FTTH– Point-to-Point (home run)– Point-to-Multipoint (PON)– Twisted pair standards too

• Publication expected September 2004


FTTH technical tutorial IEEE 802.3ah EFM status

• PON Physical Medium Dependent (PMD) based on ITU-T 983 series

• Home run PMD based on fast and gigabit Ethernet standards







• Questions

www.ftthcouncil.org

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FTTH Tutorial 8-7-03

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