Insight into Epon & Gpon

1.

Insight into EPON & GPON
Sept. 1st, 2007
2019/8/31
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2.

Outline
EPON vs. GPON
CTC EPON IOP
Summary
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3.

EPON Vs. GPON
• Protocol & Framing
• QoS & TDM Support
• System Costs
• Upgrade Path
• Interoperability & service migration
• Split ratios, maximum reach, & traffic management
• Users Forecast
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4.

PON Framing
ITU-TGPON
125 sec
ATM
125 sec
GEM
ATM
ATM
GEM
ATM
125 sec
ATM
GEM
ATM
“GPON
Lite”
GEM
IEEE EPON
GPON is evolving GEM
to look like EPON!
GEM
OAM & MPCP
No Fixed Frame
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5.

GPON Frame Details
Downstream
125 us
PCBd
n
PSync
4 Bytes
PCBd
n+1
Payload n
Ident
4 Bytes
Rate
1.244G
2.488G
125 us
PLOAMd
13 Bytes
BIP
1 Byte
PLend
4 Bytes
Coverage of this BIP
(Includes Payload n-1)
Payload n+1
Plend
4 Bytes
Frame Size
19440
38880
US BW Map
N*8 Bytes
Coverage of next BIP
(Includes Payload n)
Upstream
ONT 1
Guard
Time
2019/8/31
125 us
125 us
Frame n
Frame n+1
Gap
PLOu
PLOAMu
13 bytes
Alloc #a Alloc #a
SStart
ONT 2
DBRu 1
Payload 1
Alloc #a
Alloc #a
Gap
PLOAMu
13 bytes
Alloc #b
Rate
1.244G
2.488G
ONT n
Frame Size
19440
38880
Gap
DBRu 1
Payload 1
Alloc #b
Alloc #b
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6.

Protocol ≠ QoS
DBA
(Out-of-Scope)
OAM
(In-Scope)
Framing
(In-Scope)
Physical Layer
(In-Scope)
Neither the EPON nor the GPON specification defines the QoS mechanism
(DBA algorithm); it is out-of-scope, meaning it is up to the system/chip vendor.
EPON and GPON have identical service requirements.
High-performance, QoS-capable systems can be built with either protocol.
Evaluate PON systems on performance and price, not protocol.
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7.

End-To-End Service Architecture
PSTN
C
I S C
O
S
Y S T E M
Core
Network
S
Home
Network
Soft Switch
OLT
Triple-Play
FTTH ONT
Video / IP
STB
PON System: A L2/L3/L4 Ethernet Switch
• Connects the Core & Home Networks
• Multi-service
• Strict enforcement of service contracts
• Designed to reduce end-to-end cost
VoD Server
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8.

TDM Services over xPON
• Telco-grade QoS is required
• Jitter, wander, delay, Stratum-traceability
Apartment Building
Cell Site
• Must be compatible with triple-play networks
• EPON & GPON: identical service-layer
requirements for TDM.
Copper
Network
Mgmt
Channel Bank
Video
Network
E1
Data
Network
GbE
ONT
n x E1
TDM
Network
Ethernet Switch
ONT
Business
Optical
Line
Terminal
E1
ONT
Central Office
GbE
PSTN
ONT
ONT
ONT
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9.

GPON Has More Complex Chips and Buffers
• GPON uses GEM to Segment and Reassemble Ethernet frames
• Each connection (Port-ID) requires a separate SAR buffer
• An additional 1MB external buffer memory is required
GPON
GPON OLT
EPON OLT
Q3
Q4
Q5
Q6
Port 1
Port 2
Scheduling
PON-IF
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Q2
Q3
Q4
Q5
Q6
Q7
9
Port 1
Q1
Q7
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EPON ONU
Port 2
Q2
Q5
Q7
EPON
PON-IF
Q1
Q4
Q0
Frame Processing
• Segmentation
buffers for every
Port ID
Scheduling
Q0
NNI Port
GPON ONU
Q3
Q6
Segmentation &
Re-assembly
(SAR) Buffers
Q7
Q2
Classification
Q6
Scheduling
Q5
PON-IF
Q4
Q1
PON-IF
Q3
Classification
Q2
Q0
Frame Processing
Scheduling
Q1
NNI Port
• 100’s to 1000’s of
SAR buffers
• Frame from ONU
must wait until all
bytes are received
upstream from ONU
before it can be
processed
Q0
Classification
GPON OLT
GPON ONU

10.

EPON Uses Less Expensive Optics – Proven
GPON
1G/2G/10G EPON
Downstream
data rate (Mbps)
1244 or 2488
1000, 2500, 10000
Upstream
data rate (Mbps)
155, 622, 1244
1000
Payload encapsulation
Laser on/off
AGC
CDR (Clock Data Recovery)
GPON Encapsulation Method (GEM)
Ethernet framing
13 ns *
44 ns *
512 ns
400 ns
400 ns
* Short laser on/off times in GPON require high-speed laser drivers
* Short AGC intervals in GPON require optical power leveling
– Additional protocol to negotiate power level
– Digital interface to transceiver to set the values
* Relaxed optical specification parameters in EPON less expensive devices
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11.

Two Very Different Choices
Support for Advanced Services
802.3ah EPON
Continuity of Services
& Network
Management.
100% Ethernet
Seamless Migration
2.5 Gb/s
EPON
1.25 Gb/s
EPON
X
X
ATM
BPON
622 Mb/s
2019/8/31
10 Gb/s
EPON
100% Ethernet
Seamless Migration
New Protocol Forklift Upgrade?
1.25 Gb/s
?
No roadmap beyond
2.5G for GPON.
2.5 Gb/s
GPON
Disruption of Services &
Network Management.
ITU-T GPON
2.5 Gb/s
Speed
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10Gb/s
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12.

1.25 & 2.5 Gb/s EPON: Line Rates & Framing
1.25 Gb/s Downstream
Line Rate:
Data Rate:
Line Encoding:
MPCP Timing:
1.25 Gb/s (.8 ns per bit)
1 Gb/s (1 ns per bit)
8B/10B
Time Quanta (16ns units)
64 bits of
Preamble
1518 Byte Packet
PRE
1518 Byte Packet
PRE
2.5 Gb/s Downstream
Line Rate:
Data Rate:
Line Encoding:
MPCP Timing:
2.5 Gb/s (.4 ns per bit)
2 Gb/s (.5 ns per bit)
8B/10B
Time Quanta (16ns units)
64 bits of
Preamble
1518 Byte
2019/8/31
P
1518 Byte
P
1518 Byte
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P
1518 Byte
P
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13.

Backward & Forward Compatibility
1.25G
1.25G
1.25G
1.25G
2.5G
1.25G
1.25G
1.25G
1.25G
1.25G
1.25G
2.5G
1.25G
1.25G
1.25G
2.5G
2.5G
2.5G
2.5G
2.5G
2.5G
2.5G
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1.25G
1.25G
1.25G
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14.

Progression from 1G to 10G EPON
802.3ah: 1 Gbps downstream / 1 Gbps upstream
The first commercial FTTH technology with Gigabit bandwidth deployed in the world
Currently specified in IEEE Std. 802.3-2005
OLT
ONU
IPTV (200 Mbps), On-Demand (200 Mbps), Internet (600 Mbps)
PS
HTTP, FTP, Gaming, Video Telephony (1 Gbps)
Option 1: 10 Gbps downstream / 1 Gbps upstream
Providing more downstream bandwidth to support advanced digital TV services
CATV replacement
OLT
IPTV (5 Gbps), On-Demand (2.5 Gbps),
Internet, Gaming, etc. (2.5 Gbps)
ONU
PS
HTTP, FTP, Gaming, Video Telephony (1 Gbps)
Option 2: 10 Gbps downstream / 10 Gbps upstream
Support for advanced, bandwidth-intensive upstream and downstream services
Support for more subscribers / dense deployments / MDU markets
OLT
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ONU
IPTV (5 Gbps), On-Demand (2.5 Gbps),
Internet, Gaming, etc. (2.5 Gbps)
PS
Massively Multiplayer Gaming, Video
Surveillance, Video Telephony (10 Gbps)
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15.

Interoperability & Service Migration
“Full” Specification
(ITU-T GPON)
“Open” Specification
(IEEE EPON)
Management Layer
(In-Scope)
Management
Management Layer
Layer
(Out-of-Scope)
(Out-of-Scope)
Why are these different?
Services Layer
(In-Scope)
Services Layer
(Out-of-Scope)
System Layer
(Out-of-Scope)
Allows Telcos & OEMs to
differentiate products
System Layer
(Out-of-Scope)
“Upper” PON Layer
(Out-of-Scope)
DBA Algorithm, etc.
“Upper” PON Layer
(Out-of-Scope)
“Lower” PON Layer
(In-Scope)
“Lower” PON Layer
(In-Scope)
Different Objectives Different Scopes
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16.

Scope of the IEEE 802.3 Standard
Open Systems
Interconnection (OSI)
Reference Model
IEEE 802.3
Layering Diagram
Logical Link Control
Application
Presentation
MAC Control
Media Access Control (MAC)
Reconciliation
Session
Gigabit Media
Independent
Interface (GMII)
Transport
Physical Coding Sublayer (PCS)
Network
Data Link
Physical Medium Attachment (PMA)
Physical Medium Dependent (PMD)
Medium
Dependent
Interface (MDI)
Physical
Medium
IEEE 802.3 covers only the Physical Layer & part of the Data Link Layer
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17.

Interoperability: Two World Views
World View 1: PON equipment that complies with a complete
specification, such as ITU-T GPON, is mandatory.
• Aspiration: A “complete” specification leads to interoperable
equipment from multiple suppliers, leading in turn to lower
cost.
World View 2: PON equipment that allows transparent re-use of existing
IP-based services is mandatory.
• Aspiration: Interoperability at the service and management layers with
other access systems (e.g., DSL).
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18.

Split-Ratio Myths
Logical vs physical split-ratio limits
• Logical
– One BPON OLT can address 253 BPON ONUs;
– One GPON OLT can address 4k GPON ONUs;
– One EPON OLT can address 32k EPON ONUs.
• Physical
– In real deployments, all technologies are limited to 1x32 or 1x64, depending on
reach, condition of the fiber plant, service mix, optical performance.
– There is no practical split-ratio limit for any of the PON protocols; all have ample
“ONU address space.”
Myth: “EPON is only a 1x16 solution, while GPON supports 1x128”
• Statements like this combine willful mis-reading of the EPON spec, which specifies a
minimum split-ratio of 1x16, not a maximum split-ratio, with some very simplistic BW
utilization calculations.
Myth: “GPON has twice the split-ratio” because it’s downstream is twice as fast as EPON’s
• 2.5G EPON is here and 10G EPON is coming soon this issue will disappear.
• Latency requirements, bandwidth guarantees, and fairness requirements are more
important than raw bandwidth.
• Stated another way, if solution A has more raw bandwidth than solution B, but cannot
distribute that bandwidth with enough precision and accuracy to meet the SLAs, then
solution A, and its higher bandwidth, are useless.
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19.

Traffic Management & Maximum Reach
Too much emphasis is placed on the PON protocol (EPON vs GPON), and too little
attention is paid to the traffic-management and service-level issues.
• The magic of EPON is not so much that it uses Ethernet framing (although that does
lead to the lowest costs), but rather that Fiberhome has built in the traffic management
functions that are really needed to make the services work properly.
• High-performance (or low-performance) systems in principle could be built with either
protocol, hence manufacturers and carriers should place highest priority on feature set
and performance, not details of the framing.
Comments on maximum reach
• Optics performance, split-ratio, and fiber-plant particulars determine the reach, not the
PON protocol. Again there is FUD that confuses minimum requirements in the EPON
standard with what is actually achievable (and legal) in real systems.
• Basically, you can dial up very long-reach PONs using any of the protocols, provided
you are willing to choose the right optics, reduce the split ratio, etc.
• None of the framing definitions contain any long-distance magic; it’s all about optics
and physics.
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20.

EPON in Asia, 2007
• Japan: 300k+ lines/month.
• NTT, KDDI, Tepco, K-Opticom, Chubu Electric, Energia, Kintetsu, & many others.
• Korea: Now in mass deployment, KT and others, 1M+ new subscribers in 2007.
• China: 50+ EPON deployments currently underway, 400k+ new subscribers in 2007.
• Taiwan, Malaysia, Singapore, Hong Kong, Thailand, Indonesia, Australia, etc.
• 6 EPON deployments currently underway (including 3 PTTs).
• Cost is key.
• Since IEEE 802.3ah approval in 2004, EPON equipment costs have decreased by
60+% and optics costs have decreased by 80+%.
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21.

2004–2009 PON Subscribers
Worldwide PON Subscribers
~ 5M EPON
end
CY2006
21.6
20
15
EP
G
10
6.8
N
O
5
N
PO
BP
2.5
N
O
CY04
CY05
CY06
CY07
CY08
Subscribers (M)
25
0
CY09
Calendar Year
Source: Infonetics Metro Ethernet Equipment, April 2006
With permission: Copyright © 2006 by Infonetics Research, Inc
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22.

2005–2011 FTTH Subscribers
Source: HEAVY READING | VOL. 4, NO. 9, JUNE 2006 | FTTH WORLDWIDE MARKET & TECHNOLOGY FORECAST
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23.

Connecting two Ethernet networks
Ethernet-over-GEM-over-SDH or Ethernet?
ITU-T GPON or IEEE EPON?
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24.

Lessons from History
• Ethernet has won every time it has competed with “higher speed” and
“higher efficiency” technologies
– Ethernet vs. Token Ring
– Ethernet vs. FDDI
– Ethernet vs. ATM
– Ethernet vs. SONET
– Ethernet vs. ATM in the DSLAM
– Ethernet vs. Multi-service in the Metro
• Ethernet is cheap, simple, easy to install & manage
Prediction
Ethernet all the way will win a large fraction of the market.
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25.

Outline
EPON vs. GPON
CTC EPON IOP
Summary
2019/8/31
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26.

CTC EPON IOP Key Features
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27.

CTC EPON System Evaluation Test
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28.

CTC EPON System Evaluation Test Achievements
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29.

CTC View of EPON
EPON is mature and suitable for mass deployment in CTC
–Simple, easy to develop
–Sufficient chip and system vendors
–Large-scale, all-around, chip-level and system-level IOP
–Mass deployment in east Asia
–Stable operation in the field trial of CTC for one and a half
years
–Decreasing cost
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30.

CTC View of EPON (Cont.)
After improved by CTC spec, EPON has no distinctive and
essential difference in technical capability compared with
GPON
-Transport capability
-DBA & QoS
-Operation & Management
-Security
-Multicast
-Fiber protection
-Multi-play support
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31.

NTT View of EPON
“Two types of giga-bit PON systems have been standardized: G-PON
by ITU-T and GE-PON by IEEE. Now the question is which one is
more promising? ... In Japan, we have seen a drastic price
reduction of media converters which could be realized by sharing
the technology and products of the LAN market. For services, high
quality IP Telephone and IP video are becoming critical basic FTTH
services. And for the core network, in NTT we have a full IP
backbone network for the FLET’s service. Switches and routers in
the network employ Ethernet interfaces. Given these factors, we
decided to develop GE-PON as the next-generation FTTH system.”
----Hiromichi Shinohara, Director of NTT Access Labs
(IEEE Communications Magazine, September 2005)
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32.

Outline
EPON vs. GPON
CTC EPON IOP
Summary
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33.

Summary
1. EPON is more mature & cost-effective than
GPON.
2. Both GPON & EPON will coexist in a long time.
3. Fiberhome is a FTTH leader in China.
4. With our effort, Fiberhome FTTH system will be
deployed worldwide soon.
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34.

Thank you for attention!
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