These are sample slides taken from my 4 days long "GPON-FTTx" training course. This course has over 380 slides and it is a great source of learning about various topics related to GPON & FTTx. There are tons of exercises and real-world examples provided in teaching material.

1. 4 Days Course on
GPON-FTTx
Instructor: Azhar H Khuwaja (M.Engg:, MEF-CECP)
azhar.khuwaja@yahoo.ca
1

2. GPON - FTTx
Agenda of Day 1
q What is Access Network?
q What is FTTx?
q What is PON?
q Fiber Fundamentals
q Protection (Redundancy)
q Questions / Review Day 1
2

3. Hierarchical Network Infrastructures
Long Haul 100s-1000s Km
Mesh or Point-to-Point
Metro enterprise 10s of Km
Rings
Access few Km
Hub Rings or Point-to-Multipoint
Users
Provide typical examples of each level?
3

4. Access Network Topologies
Draw splitter based Point-to-Multipoint !!
Chain
Ring
Point-to-Multipoint
OLT
ONU
ONU
ONU
OLT ONU ONU
OLT
ONU
ONU
ONU
Service
Provider
Service
Provider
Service
Provider
4
EP2P

5. Multi Service Access Network
OLT
PSTN
IP TV
ATM
IP ISDN
POTS
ONU
SDHSDH
ONU
ONU
ADSL
VoIP
Ethernet
Service NodesService Nodes User NodesUser Nodes
ONU
Internet
ONU
Street cabinet
Copper Cable
Inside Central Office
5

6. Multi Service Access Network
• VDSL is Very High Speed Digital Subscriber Line
• V.24 is a ITU-T standard for the interchange of serial binary data between two devices, e.g. the connection of a computer with a
telephone modem.
OLT
ONU
Voice
Gateway
PSTN
ATM
ONU
ONU
155M
/622M
V5
E1
ONU ONU
POTS
ADSL
V.24
FE
2B+D
VDSL
NMS
IP
NG SDH
FE/GE
ONU
6

7. Types of Sites
• New build where the network will be
introduced simultaneously as the
buildings.
Greenfield
Brownfield
• Where there are existing buildings and
infrastructure but the infrastructure is to
a lower standard.
Overbuild
• Adding to the existing infrastructure.
7

8. Different Fiber Termination Points (FTTx)
POP / Central Office Access Loop Customer Premises
Fiber to the POP
Fiber to the Curb
Fiber to the Building
Fiber to the Home / Apartment
Curb
xDSL over Copper
xDSL over Copper
FTTx denotes Fiber Termination Points
Existing CAT 5 DSL
Red Line = Fiber
Yellow Line = Copper
8

9. Different Fiber Termination Points (FTTx)
FTTH / FTTP
FTTN
FTTC
Central Office
OLT
Splitter
Fiber
Fiber
ONU
ONU
ONU
ONU
Optical Distribution Network
Copper (DSL) / Coax
Red Line = Fiber
Yellow Line = Copper
ONU & OLT are not part of ODN
9

10. Expectations from FTTH
• Provision of high bandwidth services and content to each customer
• Flexible network architecture design that can accommodate future needs
• Support for future network upgrade and expansion
• Avail all benefits of Fiber compare to Copper / non-fiber mediums (e.g. Microwave)
Limitations of non-fiber solutions (makes FTTH better choice)
• Twisted copper pair(s)
o 8 Mbps @ 3 km, 1.5 Mbps @ 5.5 km (ADSL)
o 1 Gbps @ 100 meters (802.3ab)
• Microwave
o 70 Mbps @ 30 km (WiMax)
• Coax
o 10 Mbps @ 3.6 km (10BROAD36)
o 30 Mbps @ 30 km (cable modem)
Note: Higher Bandwidth @ longer distances is just one aspect of Fiber’s supremacy!
Fiber is “future proof” (no need to replace it for future higher BW requirements).
10

11. Fiber to the Curb (FTTC)
Nsubscribers
Core / Metro
Network
Access Network
Copper Cable
• Use Hybrid Fiber Coax & VDSL
• Transceiver located at curb
• Only 2 optical transceivers
• Lacks end-to-end fiber solution
• Lower Bandwidth from curb to subscribers
POP / CO
Fiber
11
What is common between FTTC &
MSAN?

12. Curb Switched Network for Fiber to the Home (FTTH)
Nsubscribers
Core / Metro
Network
Access Network
Fiber
• Switch located at Curb
• Need (2xN)+2 optical transceivers
• Expensive solution
• High bandwidth to subscribers
POP / CO
Fiber
12

13. Point-to-Point Network for Fiber to the Home (FTTH)
Nsubscribers
Core / Metro
Network
Access Network
• No Curb role as every fiber departs from switch to home directly
• Need 2xN optical transceivers
• Expensive solution (lengthy fiber cost per subscriber)
• High bandwidth to subscribers
• Complicated solution
• FTTH brings fiber inside house whereas FTTP terminates in front of the house
• EP2P can be an example of this type (Ethernet Switch is located in POP)
POP / CO
Fiber
13

14. Passive Optical Network for Fiber to the Home (FTTH)
1:8 passive splitter
Nsubscribers
feeder fiber
Core / Metro
Network
Access Network
N can be 2, 8, 16, 32, 64, 128
• No Curb role
• Less wiring at Point of Presence
• Only N+1 optical transceivers (9 in this case)
• Economical solution (due to splitters)
• High bandwidth to subscribers
• Relatively easy to upgrade and maintain
POP / CO
14

15. What is Passive Optical Network ?
• PON has OLT at CO, one fiber to splitter and fan-out towards subscribers, each having
ONU, where the fiber is terminated.
• PON uses passive architectures and passive components
• Passive components are optical star coupler/splitter, static wavelength router etc
• Reliable, easy to maintain, not to be powered, transparent to bit rates and modulation
schemes, easily upgradable without changing infrastructure
• Shared infrastructure results in lower cost per customer
• All PON systems are based on point-to-multipoint physical topology
• Fiber data-rate can be upgraded as technology improves
downstream
Optical Network Units
upstream
Optical Distribution Network
NNI
CPE
UNI
Core / Metro
Network
Splitter
Optical Line Terminal
Passive Optical Network
15

16. PON principles (generally applicable to all xPON)
• Based on ITU-T’s G.982
• Both OLT & ONU support layer 2 technology
• OLT broadcasts data downstream to all ONUs
• ONU captures data destined for its address and discards all other data
• ONUs share bandwidth using Time Division Multiple Access
• OLT manages the ONU timeslots
• Encryption applied to downstream traffic for ensuring privacy
• Ranging is performed to determine ONU-OLT propagation time
• xPON band-plan
Upstream: 1260-1360nm (1310±50) Downstream: 1480-1500nm (1490±10)
• PON has a special architecture;
Broadcast Point-to-Multipoint in downstream direction
Multiple Access Multipoint-to-Point in upstream direction (actually Point-to-Point)
• PONs employ auto-discovery mechanism to automate discovery of ONUs
• 1625/1650nm is a testing wavelength used in FTTx.
16

17. Passive Optical Network benefits
• Shared infrastructure translates to lower cost per customer
• Minimal number of optical transceivers
• Feeder fiber and transceiver costs divided by N customers
• Greenfield per-customer cost similar to UTP
• Passive splitters can be installed anywhere and no power needed
• Use two multiplexing techniques; TDM based PONs and WDM based PONs
• Dynamic allocation of upstream bandwidth (efficient utilization)
• Use of encryption for privacy
• Reach Extender (G.984.6) can significantly increase OLT to ONU distances (60km)
• Uses FEC for reliable transmission
• Can support up-to 32dB loss (power budget) by using Class C+ optics
• Passive splitters results in lower cost
• Less complex network & easy to troubleshoot
• Reduced fiber usage
17

18. PON Elements & Terminology
OLT (Optical Line Termination/Terminal):
o Exists in the data center and acts as the single connection point for Voice, Data, &
Video. The output from OLT after it converts electrical signals to light (photonic) uses
single mode fiber cable to supply the enterprise.
o Contain optical transceiver using different ls for transmit & receive (Wavelength
Division Duplex) along with sophisticated hardware
o Normally located at POP/CO and referred as Access Node (CO head-end)
o Another name used for OLT in some references is Enterprise Aggregation Switch.
downstream
ONUupstream
Optical Distribution Network
NNI
CPE
UNI
Core / Metro
Network SplitterOptical Line Terminal
Passive Optical Network
ONU
ONU
ONU/CPE
18

19. PON Elements & Terminology
ONU / ONT (Optical Network Unit / Optical Network Termination/Terminal)
o ONU receives the communications from optical splitter & supplies the voice, video, &
data signals to end-user devices.
o Sometimes ONT is referred as Optical Workgroup Terminal.
o ONU exists in several versions including MDU ONUs.
o ONU_ID is an 8 bit identifier that an OLT assigns to an ONU during ONU activation.
The ONU_ID is unique across the GPON & remains valid until the ONU is powered off
or deactivated by the OLT.
downstream
ONUupstream
Optical Distribution Network
NNI
CPE
UNI
Core / Metro
Network SplitterOptical Line Terminal
Passive Optical Network
ONU
ONU
ONU/CPE
19

20. PON Elements & Terminology
• ODN (Optical Distribution Network):
o Entire fiber tree including feeder, splitters, distribution fibers etc. except OLT & ONU.
o Totally passive without any power requirement.
• Feeder Cabling:
o Large size optical cables & supporting infrastructure like ducting or poles.
o Several kilometers length from OLT to Primary Fiber Concentration Point (FCP).
o Downstream is from OLT to ONU (Upstream is the opposite direction).
o Both directions of traffic run over same fiber.
ONU
Optical Distribution Network
NNI
CPE
UNI
Core / Metro
Network SplitterOptical Line Terminal
Passive Optical Network
ONU
ONU
ONU/CPE
Feeder Cabling
FCP
20

21. PON Elements & Terminology
• Internal Cabling:
o Internal cabling consists of external building fiber entry devices, internal fiber cabling
& final termination unit which may be part of ONU.
Picture showing Feeder, Distribution, & Drop Cables
21

22. PON Elements & Terminology
• Optical Distribution Frame (ODF):
o ODF is interface between outside plant cables & the active transmission equipment.
o ODF is a patching frame for optical fibers.
o ODFs are usually situated in CO and can connect up-to 1400 fibers.
o Large COs use multiple ODF cabinets.
• Optical Splitter:
o Connects to single-mode fiber from OLT & passively redistributes the signal up to 64
times (in case of 1:64 splitter).
o Two common types of PON splitters;
Fused Biconical Taper (FBT) & Planar Lightwave Circuit (PLC)
o PLC has better insertion loss and uniformity at higher wavelengths compared to FBT
over all bands. PLC are compact & provide higher split ratios.
o Centralized splitting vs. Distributed splitting (one splitter vs. cascaded splitters)
o 1:128 split using GPON is between realistic & un-realistic
22

23. FTTH Network Cabling
What is Home Pass/Home Connected?
A marketing term shows percentage of homes subscribed to particular operator.
Ideally cent percent.
23

24. PON types
Several PON types have been defined;
APON (ATM PON)
BPON (Broadband PON)
GPON (Gigabit capable PON)
EPON/GEPON (Gigabit Ethernet PON)
CPON (CDMA PON)
WPON (WDM PON)
OLT
ONT (ONU)
ITU-T prefers using ONT (rather ONU) in technical documents.
PON is a group of technologies originally created by Full Service Access Network (FSAN)
working group and now standards of ITU-T and IEEE, allowing fiber as the first mile (or last
mile) to the customer premises.
What is First Mile and Last Mile ?
Which one are TDM PON?
24

25. xPON Bandwidth Comparison
PON Downstream (Mbps) Upstream (Mbps)
BPON 155.52 155.52
BPON amendment 1 622.08 155.52
BPON amendment 1 622.08 622.08
BPON amendment 2 1244.16 155.52
BPON amendment 2 1244.16 622.08
GPON 1244.16 155.52
GPON 1244.16 622.08
GPON 1244.16 1244.16
GPON 2488.32 155.52
GPON 2488.32 622.08
GPON 2488.32 1244.16
GPON 2488.32 2488.32
EPON/GEPON 1250 1250
10GEPON 10,312 1250/10,312
GPON identifies 7 transmission speeds as shown above.
Main-stream transmission
speed
Source: ITU-T 25