This document provides an overview and roadmap for achieving broadband optical access of 10Gb/s everywhere. It discusses: 1) The TSB Photonics21-NGOIA project which aims to identify promising approaches to achieving ubiquitous 10Gb/s access. 2) A paradigm shift in optical networking towards more flexible, dynamically reconfigurable networks to improve energy efficiency. 3) The concept of an "ultimate" optical network architecture with a common infrastructure across access, metro and backbone networks to maximize statistical multiplexing gains and reduce costs. 4) Several candidate technologies for next-generation optical access such as long-reach PON, WDM-PON and hybrid TDM/W

1. Photonics21  Next Generation
Optical Internet Access:
Roadmap for Broadband Optical Access towards 10Gb/s
Everywhere
Dr Kyeong Soo (Joseph) Kim (k.s.kim@swansea.ac.uk)
Institute of Advanced Telecommunications

3. Outline
• Swansea & Swansea University
• TSB Photonics21–NGOIA Project
– Business & Architectural Issues
– Paradigm Shift in Optical Networking
– Ultimate Optical Network Architecture
– Toward Next-Generation Optical Access
• Summary

4. SWANSEA & SWANSEA
UNIVERSITY

5. Where is Swansea?
WalesSwansea Cardiff - Welsh Capital
Less than an hour away
by car or train
London – UK Capital
Less than three hours
by car or train
(192 miles)

6. Swansea University
•29th university
established in the UK
•King George V laid the
foundation stone in July
1920
•Now over 12,000
students
–1,800 international

7. Swansea University
The University stands in parkland overlooking Swansea Bay on the edge of
the Gower Peninsula, Britain's first “Area of Outstanding Natural Beauty”.
Beach

8. World-Class Research
• Why should you be interested in research?
• 4 world-class research centres
• 5* research ratings – one of only 3 in the UK
• Strong links with industry E.g. Rolls Royce,
Siemens, IBM, Esso, BP Chemicals, Ford,
BT, Procter and Gamble
• Many of our industrial partners offer
sponsorship and prizes
• Recent research projects have included:
Millennium Stadium, Supersonic Thrust Car
• 3 world-class research centres
• Civil and Computational Research Centre
• Materials Research Centre
• Multidisciplinary Nanotechnology Centre
• Within top 8 Eng. Dept. in the UK
• Strong links with industry
• NASA, Rolls Royce, Airbus, European Space
Agency, BAE systems, Siemens, IBM, Motorola,
BT, Ericsson, Esso, BP Chemicals, Texaco, Ford,
Procter and Gamble, Corus, …
• Recent research projects including
• Millennium Stadium, Supersonic Thrust Car,
Airbus A380, NASA space shuttle, …
World-Class Research

9. Scholarships
• Zienkiewicz Scholarships (MRes, PhD)
– Full fees plus generous stipend
• Erasmus Mundus MSc in Computational Mechanics
– Worldwide cooperation and mobility programme
– €42,000
• School of Engineering Scholarships
– For both undergraduate and postgraduate

10. TSB PHOTONICS21–NGOIA PROJECT

11. Aim
• To identify promising routes forward in achieving the
goal of “10 Gb/s everywhere”, while making best use of
the existing knowledge that has been gained in earlier
projects.
– The solutions will show most promise of cost
effectiveness, be future proof (i.e., allowing
bandwidth evolution and infrastructure reuse) and
allow simple interfaces which can be standardized.

12. Partners
• 5 Industrial Partners
– Oclaro (Bookham)
– BT
– Ericsson
– CIP
– Gooch & Housego
• 4 Academic Partners
– Cambridge
– Essex
– Swansea
– UCL

13. Target FP7* ICT Work Programme 2009-10
• Objective ICT-2009 3.7: Photonics: €60M
– Photonics21** ERA-NET*** Plus: €10M
• On the FTTH broadband infrastructure providing
1 Gb/s data rates for every household, scalable
to 10 Gb/s.
* FP7: the Seventh Framework Programme for Research and Technological Development
** Photonics21: A European Technology Platform
*** ERA-NET: European Research Area-Network

14. BUSINESS & ARCHITECTURAL
ISSUES

15. FTTH* vs. Cloud Computing**
SaaS*** User
SaaS Provider/
Cloud User
Cloud Provider
Web Apps
Utility computing
vs.
* NGOA Workshop, Mar. 2008.
** “Above the clouds”, UC Berkeley.
*** SaaS: Software as a Service

16. FTTH Business Perspective*
Layer Economic
Character
Life Cycle Cost per
Subscriber
Service Layer Low CapEx,
average to high
OpEx
1 to x years ?
Active Layer Average CapEx,
low OpEx
5 to 10 years €300~500
Passive Layer High CapEx, very
(very) low OpEx
25 to 50 years €500~700
•NGOA Workshop, Mar. 2008.

17. Cloud Computing: New Aspects in Hardware*
• The illusion of infinite computing resources available on
demand
– Through the construction of large-scale, commodity-computer
datacenters at low cost locations, and virtualization technique
• The elimination of an up-front commitment by Cloud users
– Companies can start small and increase gradually
• The ability to pay for use of computing resources on a
short-term basis as needed
* “Above the clouds”, UC Berkeley.

18. Cloud Computing: Economic Benefits*
• Elasticity
– Ability to add or remove
resources at a fine grain
and with a small lead time
• Transference of risks of
– Overprovisioning
(underutilization)
– Underprovisioning
(saturation)
* “Above the clouds”, UC Berkeley.
Max. (=peak)
Min.
Avg.
Time
Demand

19. Cloud Computing: A New Killer Application for
Next Generation Optical Internet Access?
• Data transfer bottlenecks (to and from Clouds)
– Example: Move 10 TB from UC Berkeley to Amazon in
Seattle*
• WAN link of 20 Mb/s: 4 Msec ≈ 46 days
• Overnight shipping (FedEx): 1 day (i.e., 1.5 Gb/s)
• 10 Gb/s link: ≈ 2 hours
» Even better if we could use more than 10
Gb/s for a short period!
* “Above the clouds”, UC Berkeley.

20. ULTIMATE OPTICAL NETWORK
ARCHITECTURE

21. Current Network Limitations
• Bandwidth-hungry services (e.g., VOD, IPTV):
– Increase the amount of network infrastructure
– Increase the network energy consumption
– Increase the data-driven network crashes
• Due to:
– Unbalance in capacity between core and access
– Mismatch between service/usage models and network
infrastructure
– Large number of power-hungry and error-prone electrical
components/systems

22. Paradigm Shift in Optical Networking
• Changes in network architectures
– Performance  Energy efficiency driven
– Static  Dynamically reconfigurable network
– Dedicated  Shared resources
– Separate & complicated  Integrated &
simplified management layers/interfaces
– Unbalanced  Balanced bandwidth link utilization

23. Traditional Way of Using Wavelengths
TX
TX
TX
TX
RX
RX
RX
RX
SW SW

24. Optical Network with
Passive/Semi-passive Nodes
New Way of Using Wavelengths
Tunable
TX
SW
Tunable
TX
SW
Tunable
TX
SW
Fixed
RX
SW
Fixed
RX
SW
Fixed
RX
SW

25. Continuous vs. Burst-Mode Communications
TX RXSW SW
...010110100101110100101001001010101111101001010101…
SONET/SDH
Packet Packet Packet
RX SW
10011…0110
Packet Packet Packet
011…010 011…010

26. Enabling Technologies
• Common denominator in technologies enabling
flexible, dynamically-reconfigurable optical networks
– CWDM
– Tunable filters
– Tunable lasers
– Burst-mode communications
• The paradigm shift pushes these technologies
towards the edge of the networks!

27. Ultimate Optical Network Architecture - 1
• A common network
architecture/infrastructure
for access/metro/backbone
• To enjoy the benefits of
Economy of Scale* by
maximizing statistical
MUXing gain over
– Traffic burstiness
– Different usage patterns
• Challenge: How to
integrate them all?
27
Backbone/CoreBackbone/CoreMAN
Access
Access

Residential
Users
Business
Users
Access/MAN/Backbone


Residential
Users
Business
Users
* Factors of 5 to 7 decrease in cost (“Above the clouds”, UC Berkeley)

28. Ultimate Optical Network Architecture - 2
• Network resource as
utility
• Cut the (static) link
between fibre
infrastructure and pool of
transceivers
• Challenge: Everything
(both up- and downstream)
in burst-mode
communications
28
Fibre Infrastructure
(Access/MAN) …
Transceivers
X

29. Ultimate Optical Network Architecture - 3
…
…
…
…
… …
…
P-T-P & WDM-PON
TDM-PON
Hybrid PON
(with advanced architecture)

30. Ultimate Optical Network Architecture:
Example
SUCCESS-HPON – Hybrid TDM/WDM-PONs
(2003-2005)
Central
Office
RN
RN
RN
RN
’
1, 2
1
2
21
22 23
’
1
’
3, 4, …
1, 2
3, 4, …
3
’
3
3
31
32
33
TDM-PON ONU
RN TDM-PON RN
WDM-PON ONU
RN WDM-PON RN
Central
Office
RN
RN
RN
RN
’
1, 2
1
2
21
22 23
’
1
’
3, 4, …
1, 2
3, 4, …
3
’
3
3
31
32
33
TDM-PON ONU
RN TDM-PON RN
WDM-PON ONU
RN WDM-PON RN
Protection & restoration is
possible by using different s
on east- and west- bound.

31. Benefits of Flexible Architecture
R
Tunable
TX 1
Power
Splitter
WDM
DEMUX
ONU 1
ONU 16
...
Start small and grow gradually

32. Benefits of Flexible Architecture
R
R
Tunable
TX 1
Tunable
TX 2
Power
Splitter
WDM
DEMUX
ONU 1
ONU 32
...
Start small and grow gradually

33. Benefits of Flexible Architecture
R
R
Tunable
TX 1
Tunable
TX 2
Power
Splitter
WDM
DEMUX
ONU 1
ONU 48
...
R
Tunable
TX 3
Start small and grow gradually

34. Benefits of Flexible Architecture
R
R
Tunable
TX 1
Tunable
TX 2
Power
Splitter
WDM
DEMUX
ONU 1
ONU 64
...
R
Tunable
TX 3
R
Tunable
TX 4
Start small and grow gradually

35. Benefits of Flexible Architecture
R
R
Tunable
TX 1
Tunable
TX 2
Power
Splitter
WDM
DEMUX
ONU 1
ONU 64
...
R
Tunable
TX 3
R
Tunable
TX 4
Flexibility and power efficiency
Usage = 50%
(Compared to Peak)
Turn off TX3 & TX4 to save energy

36. Benefits of Flexible Architecture
R
R
Tunable
TX 1
Tunable
TX 2
Power
Splitter
WDM
DEMUX
ONU 1
ONU 64
...
R
Tunable
TX 3
R
Tunable
TX 4
Redundancy and hot-swap capability
TX4 failed
The system is still running (with
slightly degraded performance)

37. TOWARD NEXT-GENERATION OPTICAL
ACCESS

38. Evolution of Optical Access
OLT
ONU
ONU
ONU
OLT
ONU
ONU

TDM-PON
OLT
ONU
ONU
ONU
ONU
OLT
ONU
ONU
ONU
? LR-PON
WDM-PON
Hybrid PON

39. Geneva, 19-20 June 2008
Evolution scenario
Now ~2010 ~2015
Power splitter deployed for Giga PON
(no replacement / no addition)
Splitter for NGA2
(power splitter or
something new)
G-PON
GE-PON
WDM option to
enable to overlay
multiple G/XGPONs
Co-existence
“Co-existence”
arrows mean to
allow gradual
migration in the
same ODN.
NG-PON2
E.g. Higher-rate TDM
DWDM
Elect. CDM
OFDM,Etc.
Equipment
be common
as much as
possible
NG-PON1 incl.
long-reach option
Capacity
XG-PON
(Up: 2.5G to 10G,
Down: 10G)
Co-existence
Component R&D to enable NG-PON2
A Suggested Time Line from ITU-T/IEEE*
* J. Kani and R. Davey , “Requirements for Next Generation PON,”
Joint ITU-T/IEEE Workshop on NGOA, Jun. 2008.

40. Areas of Improvement
• Reach
– Through amplification
• Bandwidth per subscriber
– Higher transmission rate in TDM-PON
– Introduction of WDM
• User base
– Serving both residential and business users
through common infrastructure
• Stronger protection capability for business users

41. Candidates for NGOA
• LR-PON
– 10 Gb/s over 100km with up to 1000:1 split ratios*
• WDM-PON
– Use of array of transceivers
– Lack of BW sharing
– Inventory management of ONUs with different s
– Need of colorless or sourceless ONUs
• Hybrid TDM/WDM-PON
– Use of fast tuneable lasers (and receivers)
– Flexible architecture, but complex MAC/scheduling
– How-swapping capability of tuneable components
* MIT CIPS Optical Broadband Working Group

42. Challenges
• Power Efficiency
– Number of high-powered transceivers and optical amplifiers in use
• Maintenance
– For active components and thermal optical devices in the field
• Backward compatibility
– For current-generation TDM-PONs
• Scalability
– Start small and grow gradually
• Integration with other services
– Wireless/Video overlay

43. 43
BT’s Current
UK Network
BT-21CN
Simplified UK
Network
Current Status of Network

44. Excerpts from Architecture Document
• “10 Gbit/s everywhere” is taken to mean that any customer premises can
cost-effectively access useful end-to-end symmetrical throughputs of
10Gb/s data on demand (i.e., whenever they want it but it need not
necessarily always be there).”
– Major focus on residential and SME customers.
– 10 Gb/s line rate in the access is a necessary but not sufficient condition.
– Some degree of contention assumed at various points in the network
• What is missing here?
– Description/definition which is
• Specific (e.g., What is “useful”?)
• Practical & implementable (e.g., any shared architecture can achieve this?)
• Measurable (during the operation in the field)

45. What Does “10 Gb/s” Means?
• We need a quantifiable &
measurable definition of “10 Gb/s” at
the user side for
– Comparative study of candidate
architectures
– Actual implementations
• One proposal is based on the
extension of the equivalent circuit
rate (ECR)*.
– For general services & applications
in addition to web-browsing and
interactive data
– Taking into account access/metro
part only
* N.K. Shankaranarayanan, Z. Jiang, and P. Mishra,
“User-perceived performance of web-browsing and
interactive data in HFC cable access networks,” Proc. Of
ICC, pp. 1264-1268, Jun. 2001.
Server
User
User
Candidate architecture
Server User
User
Y
Z = α*min(X, Y) (α < 1)
The same
perceived
performance
X

46. Implications on Metro/Access* Architectures - 1
• If we mean by “10 Gb/s” the (extended) ECR of
the network architecture (i.e., Z), we can derive
the following conclusions:
– Point-to-point (including static WDM-PONs)
architectures with a UNI (i.e., Y) of 10 Gb/s can meet
the requirement.
• As far as the NNI (i.e., X) is not a bottleneck.
• But there is no statistical multiplexing gain (i.e., sharing of
resources) in this architecture.
* Not end-to-end.

47. Implications on Metro/Access Architectures - 2
– Shared architectures with a UNI of 10 Gb/s may not meet this
requirement (i.e., ECR < 10 Gb/s), irrespective of NNI.
• Need to increase either line rate (for TDM-PON & hybrid
TDM/WDM-PON) or number of WDM channels (for hybrid
TDM/WDM-PON) at the UNI.
• Note that the ECR is a function of the architecture (fixed
component), the number of users, and the nature of
services/applications (variable components).
» Possible (& even desirable?) to keep the ECR constant
(i.e., 10 Gb/s in this case) by changing the line rate
and/or the number of WDM channels?

48. Summary
• Changing business environment and demands are driving
forces behind the paradigm shift in optical networking
toward
– Flexible, dynamically-reconfigurable network to better utilize
network resources
– Passive/semi-passive network to maximise energy efficiency
– A common network infrastructure for access/metro/backbone
• We plan to carry out the following tasks for realizing
NGOIA solutions scalable up to 10 Gb/s:
– Investigate candidate architectures in terms of cost, power
efficiency, maintenance, scalability, and extensibility.
– Provide a guideline for future NGOIA solutions and large-scale
European projects on this subject.

49. Questions?
Thank you for your time