Page 1
FTTH Design and Network Basics
Mark Boxer
Applications Engineering Manager, OFS
Jeff Bush
Professional Services Manager, OFS
PC-101-G
Page 2
Agenda
• Drivers for FTTx
• Why fiber
• Fiber feeds everything
• Flavors of FTTX
• Nuts and bolts – the components
• Installation techniques
• Network design configurations
Page 3
The world is changing
• In the past 15 years, we’ve seen…– The Internet
– iPods
– HDTVs
– DVRs
– Smartphones (Blackberry, iPhone, etc)
– Tablet computers• All of these revolutionary technologies require
more BANDWIDTH (telecommunications capacity)
We must expect and plan for more and faster changes in the future!
Page 4
Video on all screens - HDTV
An image is built on a screen, pixel by pixel, One HDTV program = 8-12 Mbps
Pixel
1920 pixels
1080
pixels
1 house = 48 Mbps bandwidth, just for video, today…
How about tomorrow? TV + DVR 24 Mbps
TV 12 Mbps
TV 12 Mbps
Page 5
H.262 or MPEG-
2
H.264 or
MPEG-4
Standard
Definition (SD)480p 249 7 2
High Definition
(HD) 1080i/720p 1,493 16 8
Growing FastVery High
Definition (VHD)1080p 2,986 32 16
Super HD 2160p 14,930 100 50
Ultra HD 4320p 59,720 400 200
Mature
New Standards
2D Video Format Mb/s Native
per stream
Mb/s (compressed)
Video Evolution over next 5 – 10 years
* ITU Recommendation J.601, Transport of Large Scale Digital Imagery (LSDI) applications
Source: OFS Estimates from Industry Data
T
o
d
a
y
Page 6
Video Bandwidth Growth Driving Fiber To The Home (FTTH)
Source: Technology
futures and OFS
Text Pictures Video HD SHD 3D
0
0.001
0.01
1
10
100
1,000
1980 1990 2000 2010 2020
Year
Top
Tie
r D
ata
Rat
e (
Mb
/s)
Analog
Modems
Digital
42% annual growth Increasing 4 times
every 4 years
0.1
2012 Offers
20 - 1,000 Mbps
10,000
Copper SpeedLimit
Fiber:
No limit!!*
* Fiber limit is >50 Tbps
Data Rate to Each Home
Page 7
Agenda
• Drivers for FTTx
• Why fiber
• Fiber feeds everything
• Flavors of FTTX
• Nuts and bolts – the components
• Installation techniques
• Network design configurations
Page 8
1 Fiber Cable
>50 Tbps
>5000 KM
Why Fiber?Greater bandwidth, longer distance, lowest cost per bit
Bandwidth Distance Cost per Bit
Copper
Bandwidth Distance Cost per Bit
Fiber
2400 Pair
Copper
Cable
100 Gbps
to 1 KM
Page 9
Why fiber? Lower cost, higher performance
• Metallic cable technologies are approaching their useful limits
• Copper (telephone) and coaxial cables (Cable TV)
– More expensive, less reliable, less capacity
• Wireless systems have significant capacity limitations
• Fiber optic cable is less expensive than copper, more reliable and has more capacity
Feature Benefit
High bandwidth High information carrying capacity
Low attenuation Long distances without repeaters…less expensive
Light weight Small size
Easier installationsUnobtrusive
No metallic conductors
No grounding problemsNo “crosstalk”
Passive No power requirementsNo circuit protection needed
Difficult to tap Very secure
Inexpensive Widely deployable. Cost effective
Page 10
Why fiber? FTTH lower operating expenses (OPEX) versus competing technologies
Why? Fewer truck rolls– Remote provisioning though software– Increased reliability vs copper/coax electronics in
field such DSL/HFC
Savings estimates vs DSL/Hybrid Fiber-Coax
– FTTH Opex saves $100 to $250 per subscriber vs DSL
or HFC
Page 11
Agenda
• Drivers for FTTx
• Why fiber
• Fiber feeds everything
• Flavors of FTTX
• Nuts and bolts – the components
• Installation techniques
• Network design configurations
Page 12
Wireless Loves Fiber (and vice versa)
Page 13
Flavors of FTTxFiber feeds the cell network
Mobile bandwidth demand, driven by smartphones and video, is growing rapidly
Fiber is needed to and up the tower for 4G networks and beyond
Fiber has many advantages for cell network operators, shown below:
13
Bandwidth
WeightTower loading/bracingGroundingInstallation timePower lossesSpaceCooling requirements
Page 14
Flavors of FTTxFiber feeds the Telephone and Cable Networks
Telephone: FTTN – Fiber to the Curb/NodeCable: HFC – Hybrid Fiber Coax
12 - 24 fibers
Switch or Node
Central Office OLTTwisted Pair or coax
•Fiber to the Node, Copper/coax to the home•Potential 24-100+ Mbps per subscriber (variable based on distance and metal cable quality)•Asymmetric bandwidth (more downstream than upstream)
150-1500 m5 to 100 KMTypical distance range
Page 15
Flavors of FTTxFiber feeds the Power Network
• Fiber is an integral part of the utility communications network– Substation to substation communications, broad deployment
– Equipment within substations, broad deployment
– FTTH in limited cases
– Smart grid initiatives are changing the nature of power delivery
Transmission Distribution
Nuclear
Renewable
Smart Meter
Micro Grid--:Information
--:Power
Page 16
Agenda
• Drivers for FTTx
• Why fiber
• Fiber feeds everything
• Flavors of FTTX
• Nuts and bolts – the components
• Installation techniques
• Network design configurations
Page 17
FTTH Electronics
Unmanaged Switch
OLT
Encoder & DVD
Fiber Management
A typical FTTH network has an “Optical Line
Terminal” (OLT) or switch at the “Headend”
or “Central Office”
The OLT or switch converts incoming traffic into
laser pulses and sends them down the fiber.
…And an “Optical Network Terminal” (ONT), media
converter, or gateway in the home. The ONT
converts the signals from light to electrical signals.
The ONT contains ports to distribute signals on the
existing home wiring (or wirelessly).
The ONT may be either inside or outside the home.
Fiber ONU
Page 18
Typical FTTH Architectures
• PON (Passive Optical Network)– Incorporates a signal divider, such as
an optical power splitter
– One fiber at the central office feeds many fibers in the field
– G-PON (Gigabit PON) and GE-PON (Gigabit Ethernet-PON) are the most common architectures
• Point-to-Point (“Active Ethernet”)– One fiber in the headend = one
fiber in the field
OLT
Optical power
splitter or wavelength filter
PON
Point to point
Switch
Some equipment will serve both architectures
Page 19
Summary of today’s common FTTH architectures
GPON GE-PON Point to Point (Active Ethernet)
Current gen
Next gen
Current gen
Next gen
Downstream bandwidth
2.4 Gbpstotal
10 Gbpstotal
1.2 Gbps total
10 Gbpstotal
100 -1000 Mbps per sub
Upstream bandwidth
1.2 Gbpstotal
10Gbpstotal
1.2 Gbpstotal
10 Gbpstotal
100 -1000 Mbps per sub
Typicaldistance
20 km 20 km 20 km 20 km
20 km
Wavelengths (nm), Downstream/Upstream)
14901310
15771270
15501310
1577 1270
15501310
OLT
Optical power
splitter or wavelength filter
PON
Point to point
Switch
Page 20
WDM Mux /DeMuxs
1 fiber per subscriber
975 13 151131
1086 14 161242
l1, l2
WDM Mux/DeMux
WDM Mux/DeMux
WDM Mux/DeMux
WDM Mux/DeMux
l3, l4
l15, l16
l1, 3 -15
l2, 4, -16
Typical 1 Gb/s up/down dedicated to each subscriber
Longer reach than GPON or GE-PON
Emerging technology
CO or Head End
WDM PON NetworksProvides a dedicated wavelength (light color) per customer
Page 21
Single-mode Fiber
Central Office or Head End
•Fiber to a switch or node with many ports to feed multiple customers •Uses Cat 5 or higher copper wiring or coax to the unit•Typical up to 100 Mb/s connection, limited by copper/coax bandwidth•Can be either symmetric or asymmetric bandwidth•Sometimes includes “fiber to the floor”
5 to 80 KMTypical distance range
FTTB – Fiber to the Building (MDUs)
100 m max
in building
Switch or node
Unit
Copper or coax cables
Page 22
Agenda
• Drivers for FTTx
• Why fiber
• Fiber feeds everything
• Flavors of FTTX
• Nuts and bolts – the components
• Installation techniques
• Network design configurations
Page 23
Light as a Communications MethodUsed for hundreds of years
Smoke Signals “One if by land, two if by sea”
Page 24
John Tyndall and William Wheeler
• John Tyndall, 1854
• Demonstrated that light could be guided within a liquid “Light Guide”
• William Wheeler, 1880
• Invented “Light pipes” for home lighting using reflective pipes
• Similar to concept used today for interior car illumination
http://www.fiber-optics.info/history
Page 25
Optical FiberFastest communications pipe available
Core
Cladding
Coating
Light travels in core and is constrained by the cladding
Acrylate coating protects pure silica (glass) cladding
Light ray
Page 26
vvsv
Fiber Structure
• Core - The center of an optical fiber. Contains dopants to change speed of light.
• Cladding - Outer layer of glass to contain light. Different refractive index.
• Coating - Cushions and protects fibers.
125 microns
250 microns
8-62.5
microns
Core
Cladding
Coatings
Page 27
Two main types of fibers - Single-mode and MultimodeSinglemode fiber – Carries only one mode of lightMultimode fiber – Carries multiple modes of light
Singlemode
Multimode
50-62.5
µm
corecladding
Index of refraction profiles
8-10 µm
125 µm
125 µm
Page 28
High level picture of where things go
The FTTx Network – Macro View
Aerial cable
Underground cable
Central Office /Headend
Fiber to the Cell Site Drop closures
or terminal
Fiber Distribution and Splitter Cabinet
Drop cable
Splice closures
Page 29
Typical Outside Plant Cable Types –Aerial and Underground
Ribbon Cables
Aerial Self-Supporting (ADSS),Duct and armored loose tube cables
Microcables
Blown Fiber Units
Drop Cables
Page 30
Outside Plant Fiber Optic Cable
• Most often “loose tube” cable structure
–Fibers loose in buffer tubes
• Handles stress/strain and temperature fluctuations and climatic extremes
–Also available in ribbons
–Fibers and buffers are color coded
• Underground applications
– Direct Buried – typically armored
– Duct cable
• Aerial applications
– Lashed to a messenger
– Self-supporting (ADSS, All-Dielectric, Self-Supporting
Buffer tube
Fiber
Loose buffer tube structure
Ribbon fiber and cable structure
Page 31
Inside Plant Cables
• Indoor cables are different than outdoor cables
• Most often “tight buffer” cable structure
–Provides additional protection for handling
–Facilitates connectorization
• Multiple types of cable structures
• Riser, plenum, low smoke/zero halogen products
–Designed to meet flame smoke ratings
• Yellow colored jacket indicates single-mode fiber
Page 32
Fiber management devices and closures
• Used to route and connect fibers
• Fiber management devices are used in the central office or remote cabinets
• Closures are used in the field to connect cables together
• Multiple designs available for each component
Page 33
Connectors
LC Connector
SC Connector
MPO Connector(12 fiber ribbon
connector)
• Fibers use special, precisely manufactured connectors
• Connector color indicates the polish of the connector
• Polish type indicates amount of back reflection
• Critical parameter to ensure proper transmission
Blue = “Ultra” polishGreen = “Angle” polish
Page 34
Splitters
Splitters
Splitter Distribution Cabinets
• Used with Passive Optical Network (PON) systems
• Used to split one fiber into multiple fibers
– Decreases power
– Splits bandwidth
• Split ratios are factors of 2
– 1x2, 1x4, 1x8, 1x16, 1x32, 1x64, 1x32
• Different deployment methods
– Centralized splits
– Distributed splits
– Cascaded splits
Page 35
MDU deployments
• MDU installations are different than single-family home installations
• Most MDU installations require tight bends and bend insensitive fibers
• Manufacturers have developed fibers and distribution products specifically for MDU applications
Page 36
Agenda
• Drivers for FTTx
• Why fiber
• Fiber feeds everything
• Flavors of FTTX
• Nuts and bolts – the components
• Installation techniques
• Network design configurations
Page 37
OSP Cable Placement Options
• Aerial
• Fast, minimal restoration time
• Typical choice for overbuilding existing aerial plant
• Below Grade
• Required by regulations for most Greenfield installations
• Aesthetically pleasing!
Page 38
OSP Cable Placement Options
Below Grade
• Direct Buried
• In conduit
• In gas Lines
• In sewers
Page 39
OSP Buried Considerations
• Existing neighborhood, or a new development?
• Must call your local “One Call” to locate existing utilities.
• Expose these utilities wherever you will be crossing them.
• A vacuum excavator is normally used to expose utilities. This is called “soft” excavation.
Source: FTTH Council
Page 40
Overbuilding with Buried PlantDirectional Drilling
• Bores under driveways, streets, landscape,
around existing utilities
• Least restoration of ground of buried solutions
• Ensures good aesthetics
• Higher skilled operation than other methods
• More expensive equipment
• Typically surface launched
• Pilot bore is followed by a pullback of the cable
Source: FTTH Council
Page 41
Overbuilding with Buried PlantVibratory Plow
• Lower cost option where no surface obstacles exist
• Little damage to surface, normally just leaves a
narrow slot
• Typically requires minimal restoration to the
ground after installation
• Conduit/cable is installed behind the plow blade
• Less operator expertise needed
• Normally requires only one operatorSource: FTTH Council
Page 42
Greenfield with Buried PlantOpen cut trenching
• Often lowest cost method
• Easiest to operate method, lower
skilled operator
• Requires the most restoration of the
ground of the 3 methods
• In new developments can lay
cable/conduit in common utilities
trenchSource: FTTH Council
Page 43
Splicing
• Fusion
– Most common type of splice
– Fibers joined together and melted at approximately 1600 degrees C
• Mechanical
– Common overseas
– Less common in US FTTH installations
Splice sleeve to cover completed splice
Illustration of electrodes used to form fusion splicing arc
Page 44
Optical Loss Budget
Unmanaged Switch
OLT
Encoder & DVD
Fiber Management
Designers must ensure enough light
can reach the home in both directions.
Component Typical loss values@ 1550 nm
Fiber 0.25-0.30 dB/km
Splices 0.05 dB
Connectors 0.25 dB
Splitters (1x32) 17-18 dB
Page 45
Agenda
• Drivers for FTTx
• Why fiber
• Fiber feeds everything
• Flavors of FTTX
• Nuts and bolts – the components
• Installation techniques
• Network design configurations
Page 46
PON Design Considerations
CapEx/OpEx
• Cost per Household
• Cost per Subscriber
• Cost to Connect
Scalability
• Ease of in-network additions
• Ease of network extensions
Build ability
• Ability to construction within required timelines
• Ability to construction without damaging customer relations
5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 80% 85% 90% 95% 100%
Hubbed Split $75 $81 $82 $88 $94 $95 $101 $101 $108 $114 $114 $121 $127 $127 $133 $134 $140 $146 $147 $153
Distributed Split $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99
$0
$20
$40
$60
$80
$100
$120
$140
$160
$180
Incre
men
tal
Co
st
Incremental Cost per HH Passed Relative to Take Rate
Page 47
43%
17%
32%
8%Electronics: OLT and ONT
generations
Electronics: installation labor 4
generations
Construction, Pathways, Design
ODN: Optical Fiber, Cable,
Splitters, Connections
Approximate cost proportions
Fiber Materials are only ~8% of cost per home*
Fiber Materials must last decades and support multiple generations of
electronics
FTTH Installed cost per Home*
Proper Selection and Design of the Fiber Materials (the 8%) can help lower the cost of the other 92%
* 35% take rate, costs and proportions may vary from this typical example
Page 48
Network Design Options
Home Run or “Active Ethernet”/”Point to Point Design”
CentralOffice
OLT or switch
SFU
SFU
SFU
• Fibers from the OLT/switch all the way to the home
• For PON, splitters placed in a central office• Minimizes OLT port usage
Splitter for PON systems
Page 49
PON Design Options
Centralized Design
CentralOffice
OLT
Splitter
SFU
SFU
SFUF1 Fiber
Cabinet• Splitters placed in a
cabinet or hub• Reduces OLT port usage• Requires investment in
cabinet
Page 50
PON Design Options
Distributed Design
CentralOffice
OLT Splitter
SFU SFU
F1 Fiber F1 Fiber
Splice Case
Splitter
SFU SFU
Splice Case
F1 Fiber
• Splitters placed in splice cases• Minimizes fiber sizes and splicing• Requires dedicated OLT ports
Page 51
PON Design Options
Cascaded Design
CentralOffice
OLT Splitter
F1 Fiber F1.5 Fiber
Splice Caseor Cabinet
Splitter
SFU SFU
Splice Caseor Cabinet
• Multiple splits between OLT and ONT• Balance between fiber and OLT port usage• Increased loss
Page 52
PON Design Examples
Typical Layout – Centralized Split
250 HHs
Splitter
Cabinet
Roadway
Ro
ad
wa
y
288 Fiber
F2,1-280
Dead,281-288
Feeder
Fiber
Households
Drop Pedestals
Drop Pedestal
Serving Area
288 Fiber
F2,1-288
288 Fiber
F2,1-272
Dead,273-288
288 Fiber
F2,1-264
Dead,265-288
288 Fiber
F2,1-256
Dead,257-288
Page 53
PON Design Examples
Typical Layout – Distributed Split
250 HHs
Feeder
Pick-up
Point
Roadway
Ro
adw
ay
36 Fiber
F1,1-3 (spare)
F1,4-12
F2,1-16
Dead,29-36Feeder
Fiber
1x32 Splitter
& Drop Pedestal
IN: F1,12
OUT: F2,1-32
36 Fiber
F1,1-3 (spare)
F1,4-11
Dead,12-24
F2,25-32
Dead,33-36
36 Fiber
F1,1-3 (spare)
F1,4-12
F2,1-8
Dead,21-36
36 Fiber
F1,1-3 (spare)
F1,4-12
Dead,13-36
36 Fiber
F1,1-3 (spare)
F1,4-11
Dead,12-36
Households
Drop Pedestal
Serving Area
Drop Pedestals
Splitter
Serving Area
Page 54
PON Design Considerations
1. OLT Cost per Port– As the cost per port drops, designs that require a higher utilization of ports but less
fiber and splicing become more cost effective
2. Take Rates– As take rates increase, the impact of dedicating OLT ports to a greater number of
splitters is reduced
3. Assessing Cost Impacts– When conducting a cost analysis to determine the impact of different design
approaches, it is helpful to focus only on cost that vary between the designs• Eliminate costs that are common to the designs being assessed
4. Cost Assessment Focus– Cost effectiveness can be measured in multiple ways:
• Cost per household/living unit
• Cost per subscriber
Page 55
PON Design Considerations
Example Cost Assessment
5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 80% 85% 90% 95% 100%
Hubbed Split $75 $81 $82 $88 $94 $95 $101 $101 $108 $114 $114 $121 $127 $127 $133 $134 $140 $146 $147 $153
Distributed Split $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99 $99
$0
$20
$40
$60
$80
$100
$120
$140
$160
$180
Incre
men
tal
Co
st
Incremental Cost per HH Passed Relative to Take Rate
Page 56
PON Design Considerations
Example Cost Assessment
5% 10% 15% 20% 25% 30% 35% 40% 45% 50% 55% 60% 65% 70% 75% 80% 85% 90% 95% 100%
Hubbed Split $1,502 $813 $545 $440 $377 $316 $288 $254 $239 $228 $208 $201 $195 $182 $178 $167 $165 $163 $155 $153
Distributed Split $1,980 $990 $660 $495 $396 $330 $283 $247 $220 $198 $180 $165 $152 $141 $132 $124 $116 $110 $104 $99
$0
$500
$1,000
$1,500
$2,000
$2,500
Inc
rem
en
tal
Co
st
Incremental Cost per Subscriber Relative to Take Rate
Page 57
MDU Design Approaches
1. MDU ONT
– ONT placed at existing demarcation point
– Utilize existing wiring (coax, cat 3/5) to the living units
2. Single Family ONT – Drop placed to each living unit
– ONT mounted within the living unit
3. Desktop ONT– Drop placed within living units (along molding, etc.)
Page 58
MDU Design Pros and Cons
1. MDU ONT– Avoids challenges and costs associated with retrofitting buildings
– Dependent on type and condition of existing wiring
2. Single Family ONT– Eliminates usage of existing wiring (possibly substandard)
– Cost and labor intensive
3. Desktop ONT– Minimal space requirements
– Typically requires drop to be routed through the living units (aesthetics)
Page 59
Summary
• Video, internet, and new applications are driving bandwidth increases that require fiber
• Fiber is the best method for providing low cost, high bandwidth services
– Lowest cost/bit
– Lowest OPEX
– More reliable than metallic technologies
– Lower attenuation, weight
• Fiber architectures include various versions of PON and Point to Point
• Multiple ways of deploying FTTH– Different design options for outside plant can significant impact costs and network
functionality