A. Morea and C. Colombo CommTech Talks, Politecnico di Milano, January 20, 2016

1. 1 © Nokia 20161 © Nokia 2016
Elastic Optical Devices pave the
way for Software Defined Optical
Networks
A. Morea and C. Colombo
CommeTechSpeech, PoliMi, 20-01-2016

2. 2 © Nokia 2016
• Motivations – New traffic trends
• How to increase the network capacity – Legacy networks
• Coherent technology
• How to increase the network capacity – Elastic networks
• Position
• Challenges for elastic network design and management
• Elastic optical networks – work in Nokia – Italia
• Conclusions
AGENDA

3. 3 © Nokia 2016
200km
5000km
3-fold heterogeneity:
 Connection lengths : from few 100s to several 1000s km
 Bandwidth request: from 10ths to 10s of Gbps
 Lifetime : from quasi-permanent to hour-long or shorter
Heterogeneity of demands in core networks
Motivations
New traffic trends
10G reach
40G reach
100G reach
1T reach?

4. 4 © Nokia 2016
Operators wants to increase the network capacity at lower expenses:
Maintaining its structure as much as possible
Replacing transmission opto-electronic interfaces by new ones transporting higher data-rates
10Gb/s Non-Return-to-Zero On-Off Keying (NRZ-OOK)
40Gb/s partial Differential Phase Shift Keying (pDPSK)
100Gb/s RZ-OOK (poor in terms of reach)
No possibility for upgrading capacity
 Low price for mature low-datarate technologies (e.g. 10G)
 Compliance with standards
 Need to maintain three pools of transponders with limited opportunities for sharing in dynamic scenarios
How to increase the network capacity
Legacy networks

5. 5 © Nokia 2016
Coherent technology
New transmission concept for 100Gb/s transmission
New transmission techniques were required to deal with:
 Increase of traffic capacity
 More and more dynamic traffic requests (connection hold-times and sources)
 Reduction of the optical reach of high capacity transmission based on OOK scheme
The response provided by the combination of
 Digital signal processing (DSP)
 CMOS VLSI technology
 Coherent detection
Coherent technology enabled:
 Exploits the two polarization states of the light
 Support high baud-rates  increase of channel capacity
 Support QAM modulation formats  increase of channel capacity
 Adapt the spectral occupancy to the traffic request (capacity, distance to cover)
 Allow flexibility and reconfigurations
Coherent optical transmission
Coherent
technology reduces
the overall network
cost

6. 6 © Nokia 2016
Coherent technology
Example of transmission concept for 100Gb/s transmission @ 32GBd
Laser
p/2
I1
Q1
I2
Q2
Client
T.E.
T.M.
FEC/Mapper
RF Amp
RF Amp
RF Amp
RF Amp
28Gbit/s
28Gbit/s
28Gbit/s
28Gbit/s p /2
Local
oscillator
Client
Decision
CarrierFrequency
estimation
CarrierPhaseestimation
Polarization
demultiplexing
Equaliazation
Chromaticdispersion
compensation
ADCSampling
Polarization-
diverse90
hybrid
Demapper/FEC
• Emitter: I1, I2, Q1, Q2 independent
binary 28Gbd binary sequences[1]
• Modulation of in-phase and in-
quadrature along two orthogonal
polarizations[1]
DSP processing
Emission
side Reception
side
“100G coherent commercially from 2010, Alcatel-Lucent [now
Nokia] was the 100G market leader through 2011”
From Ron Kline, Principal Analyst, Network Infrastructure

7. 7 © Nokia 2016
Coherent transmission meets capacity requirements
25Gbps 50Gbps 75Gbps 100Gbps > 100Gbps
1
2.2
2.5
0.2
1.4
BPSK
1bit/symb
PDM-BSPK
2 bit/symb
PS-QPSK
3bit/symb
PDM-QPSK
4bit/symb
PDM-xQAM
@ 32GBd – 50GHz
occupancy
It is possible to play with the baudrate
and the modulation format to obtain
diverse capacity and distance coverage
Only one device could carry multiple
baudrate and modulation formats
NRZ OOK
1bit/symb
Reach @ 10Gb/s ~ 4000km (dispersion compensated)
@100Gb/s ~ 3500km (no dispersion compensated) [2]

8. 8 © Nokia 2016
Operators wants to increase the network capacity at lower expenses:
Maintaining its structure as much as possible
Datarate variety provided by a single type of rate-adaptive transponder
100Gb/s systems with coherent detection can be made rate-adaptive through simple precoding [1]
2 polarizations x 4 phase states 100Gb/s PDM-QPSK
2 polarizations x 2 phase states  50Gb/s PDM-BPSK
1 polarization x 2 phase states  25Gb/s BPSK
Similar technology for all rates  Jointly-optimized link design, limited XPM degradation
Single pool of resources  high potential for sharing in dynamic networks
Single technology  single development cost, fast price erosion
High price for low datarates
How to increase the network capacity
Elastic networks

9. 9 © Nokia 2016 9
Position
EON allows one to adapt (thus benefit from) traffic variations and physical impairments
 Dynamic sharing of resources
 Example: in time-varying required transmission rate,
each connection is allowed to contract and expand its used
spectrum around its fixed frequency [3]
 Gains are conditional on volume of time-varying
demands and bandwidth requirements of demands sharing a link
Increased Network Capacity

10. 10 © Nokia 2016 10
Position
EON allows one to adapt (thus benefit from) traffic variations and physical impairments
 Data-rate adaptation
 Dynamic selection of modulation format to match the connection length  ~30%
capacity increase at a constant cost per Gb/s [4]
 Dynamic selection of modulation format to match the link margins with respect to the
network aging  up 10% cost savings in an up-grading network
 Flexgrid technology
 Wide-range of bandwidth demands while only partial
wavelength filling  savings of ~20% of spectrum [5]
Increased Network Capacity
60Gb/s
in
100G l
75Gb/s
in
100G l
50Gb/s
in
100G l

11. 11 © Nokia 2016 11
Position
1. Universal TSP  provision a single resource for restoration whatever the data-rate
(OEO reduction between 30%-70% [6])
 Restoration forces the use of large number of 100G channels in mixed-rate networks  Elastic
networks more cost-efficient (up to 37%) than mixed-rate networks for all but the lowest traffic
loads [7]
2. Support easily increasing traffic & network upgrades (18% lower CAPEX than MLR[8])
3. Tunable devices  No need to uninstall and replace low rate devices with higher ones
Reduced Costs

12. 12 © Nokia 2016 12
Position
To fully take advantages of Elastic Optical Networks with respect to fixed mix-rate networks
dynamic traffic scenarios are mandatory, e.g.
 Restorable[6],
[7] A. Morea et al, “efficiency gain from elastic optical networks”, ACP 2011

13. 13 © Nokia 2016 13
Position
To fully take advantages of Elastic Optical Networks with respect to fixed mix-rate networks
dynamic traffic scenarios are mandatory, e.g.
 Restorable[6],
 Network upgrades[8],
[7] A. Morea et al, “efficiency gain from elastic optical networks”, ACP 2011
0
2000
4000
6000
T0 T1 T2 T3 T4
Time
TotalCost(a.u.)
MLR
0
2000
4000
6000
T0 T1 T2 T3 T4
Time
Elastic 100G only

14. 14 © Nokia 2016 14
Position
To fully take advantages of Elastic Optical Networks with respect to fixed mix-rate networks
dynamic traffic scenarios are mandatory, e.g.
 Restorable[6],
 Network upgrades[8],
 Asymmetric traffic[9],
[7] A. Morea et al, “efficiency gain from elastic optical networks”, ACP 2011

15. 15 © Nokia 2016 15
Position
To fully take advantages of Elastic Optical Networks with respect to fixed mix-rate networks
dynamic traffic scenarios are mandatory, e.g.
 Restorable[6],
 Network upgrades[8],
 Asymmetric traffic[9],
 Dynamic traffic demands (hold-time and/or time-varying)
[7] A. Morea et al, “efficiency gain from elastic optical networks”, ACP 2011
0
1
2
3
4
5
40 50 60 70 80
Network load (Erlang)
Powerconsumption(kW)
peractiveLSP
w/ current protocol
w/ proposed protocol
(c)
0
1
2
3
4
5
40 50 60 70 80
Network load (Erlang)
Powerconsumption(kW)
peractiveLSP
w/ current protocol
w/ proposed protocol
0
1
2
3
4
5
40 50 60 70 80
Network load (Erlang)
Powerconsumption(kW)
peractiveLSP
w/ current protocol
w/ proposed protocol
(c)

16. 16 © Nokia 2016 16
Position
To fully take advantages of Elastic Optical Networks with respect to fixed mix-rate networks
dynamic traffic scenarios are mandatory, e.g.
 Restorable[6],
 Network upgrades[8],
 Asymmetric traffic[9],
 Dynamic traffic demands (hold-time and/or time-varying)
 Network aging[11]
[7] A. Morea et al, “efficiency gain from elastic optical networks”, ACP 2011

17. Challenges for elastic network design and management
OXC
OXC
OXC
OXC
OXC
(1) Build cost and
energy-efficient
rate-adaptive
transponders
TSP
(2) Predict bit error rate (BER) of connections vs
datarate, bandwidth and path characteristics
Router
Router
Router
Router
Router
TSP
(3) Interconnect
rate-adaptive
transponders
with (flex-rate)
ports on routers
and switches
(4) Develop impairment-aware algorithms for
routing, rate selection and spectrum allocation
(5) Develop
control plane
for dynamic
management of
connections
Hardware
Software

18. 18 © Nokia 2016
Many research works have been done in the recent years to investigate the interests of
elasticity in optican networks
Nokia-Italia (previous Alcatel-Lucent Italy) contributed to IDEALIST European project
 implemented a client-side controller which tune the traffic stream going from the OTN
layer to the optical one
Elastic optical networks – work in Nokia (previous Alcatel-Lucent) – Italia
Research

19. 19 © Nokia 2016
In its portfolio, Nokia has commercially-available elastic-prone devices
 400G PSE (Photonic Service Engine)[12]
Electro-optics chip capable of driving traffic up to 400 gigabits per second (Gb/s).
Versatile and scalable, it dramatically boosts the performance of 100G networks
today - and lays the foundation for 400G transport down the road. Built on in-
house Bell Labs research and extensive field experience with 100G deployments, the
400G PSE is designed specifically for our 1830 Photonic Service Switch. It delivers
4X the speed of 100G and increases the capacity of today’s transport networks, while
improving efficiency and better addressing the massive growth of broadband
traffic.
Elastic optical networks – work in Nokia (previous Alcatel-Lucent) – Italia
Product

20. 20 © Nokia 2016
To face the exponential traffic growth optical networks are looking for more cost-
efficient solutions that better fit to traffic features
An innovative network concept has been introduced: elastic optical networks
 based on tunable optical interfaces and flexible switches
The benefits of the elasticity range from the overall network cost reduction, both
in expenditure and operational, to the improvement of network scalability
In the next part of this talk, Software Defined Network architecture is presented
Conclusions

21. 21 © Nokia 2016
Any questions ?

22. 22 © Nokia 2016
Stage positions for working on elastic optical network
concepts are open in our team (network dimensioning
planning tool)
Contact point: gaetano.caldirola@nokia.com
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23. 23 © Nokia 2016
[1] A. Morea, O.Rival, Nicolas Brochier, E. Le Rouzic, “Datarate Adaptation for Night-Time Energy Savings
in Core Networks,” IEEE/OSA Journal of Lightwave Technoloty, Vol. 31, No. 5, March 2013, pp. 779 - 785
[2] http://www3.alcatel-lucent.com/features/100g_era/
[3] K. Christodoulopoulos, I. Tomkos, E. A. Varvarigos, “Time-Varying Spectrum Allocation Policies and
Blocking Analysis in Flexible Optical Networks,” IEEE Journal of Selected Aarea in Communication, Vol. 31,
No. 1, January 2013, pp. 13-25, Special Issue on Elastic Optical Transport Networks
[4] O Rival, G Villares, A Morea, “Impact of inter-channel nonlinearities on the planning of 25–100 Gb/s
elastic optical networks,” IEEE/OSA Journal of Lightwave Technoloty, Vol. 29, No. 9, May 2011, pp. 1326-
1334
[5] A Morea, O Rival, A Fen Chong, “Impact of transparent network constraints on capacity gain of elastic
channel spacing,” in Proceedings of IEEE/OSA Optical Fiber Communication conference 2011, paper
JWA62
[6] A Morea, O Rival, “Advantages of elasticity versus fixed data-rate schemes for restorable optical
networks,” in IEEE Proceedings of European Conference and Exhibition on Optical Communication, paper
Th.10.F.5
References
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24. 24 © Nokia 2016
[7] O. Rival, A. Morea,“Cost-efficiency of mixed 10-40-100Gb/s networks and elastic optical networks”,
in Proceedings of IEEE/OSA Optical Fiber Communication conference 2011, paper OTuI4
[8] O Rival, A Morea, N Brochier, H Drid, E Le Rouzic, “Upgrading optical networks with elastic
transponders,” in IEEE Proceedings of European Conference and Exhibition on Optical Communication
2012, paper P5. 12
[9] A Morea, A Lord, D Verchere, “Cost benefits of asymmetric IP-over-DWDM networks with elastic
transceivers,” in Proceedings of IEEE/OSA Optical Fiber Communication conference 2015, paper Th1I. 1
[10] A Morea, S Spadaro, O Rival, J Perello, F Agraz, D Verchere, “Power management of optoelectronic
interfaces for dynamic optical networks,” in IEEE Proceedings of European Conference and Exhibition on
Optical Communication 2011, paper 3-5
[11] J Pesic, A Morea, “Operating a network close to the “zero margin” regime thanks to elastic devices,”
in IEEE Proceedings of International Conference on Transparent Optical Networks (ICTON), 2015, paper
Th.B2.6
[12] https://www.alcatel-lucent.com/innovation/400g-pse
Proceedings
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Elastic Optical Devices pave the way for Software Defined Optical Networks
claudio.c.colombo@nokia.com
January, 2016

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Optics SDN – Proof of Concept
Software Defined Networks (SDN) is the right framework for the evolution of networking to meet cloud demands.
The abstraction between application networking requirements and actual network
implementation is the key enabler that allows applications to rapidly program the network and
consume it in an automated fashion.
SDN provides the means to manage network resources efficiently and simplify operations.
 Transport provides the foundation of the networking layer and in order to properly participate in an SDN framework, it
needs to be capable of providing resource and topology information, and be able to fulfill requests for network services
on demand using standard Application Programming Interfaces.
 SDN solutions have initially been focused on data center networking, but their applicability is now being extended to
metro and wide area networks as well.
 SDN is centered on two key objectives
— to provide service acceleration to meet application networking requirements,
— to drive operational efficiency and simplification to reduce capital and operating costs

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NSP – Network Service Platform
NSP bridges the gap between service provisioning and network engineering.
 Operators can now automate complex multi-vendor IP/optical provisioning to rapidly and
cost-efficiently define services in real-time and at scale.
 Purpose built SDN-based software gives full visibility of the state of the network across all layers at all times:
 allows automatic multi-layer service provisioning
 uses best available network resources
 creates resources in a multi-vendor and multi-technology environment
 optimizes network in real time

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NSP – the architecture
Network intelligence is logically centralized in a software based SDN Controller.
This controller maintains a global view of the network. As a result, the network appears to the applications and policy
engines as a single, logical switch. The architecture decouples the network control functions from forwarding functions
enabling the network control functions to be completely programmable and control by the operator.

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OIF/ONF Transport SDN model
Northbound
Interface (NBI) e.g.
Service Request,
Topology APIs
Southbound
Interface (SBI) e.g.
OpenFlow™
Features:
OpenFlow extensions for the Southbound Interface between Controller and Network Element
Northbound Interface Protocols – Service Request and Topology network APIs
Multi-domain controller hierarchy

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SDN main benefits: unified IP/optical management
Multi-layer resource management and control is usually disparate (managed by different tools and by different
departments). Turning up a service across an IP/Optical Network is very complex and time-consuming.
SDN brings centralized control over the multi-layer network
Integrated resource management provides unified visibility of network state across many layers
Simplified configuration (SDN pushes configuration across multiple-layers)

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SDN main benefits: multi-layer and multi-vendor capability
Multi-layer (ML) networking between the IP and optical layer places specific requirements on the interface between
layer specific controllers and the multi-layer application platform.
While standardization of this interface is in progress, both via IETF and ONF, and there seems to be consensus on
the format (RESTful), the actual data model is not yet agreed upon.

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SDN main benefits: network slicing

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NSP architecture
The Nokia Network Services Platform (NSP) is the first
carrier software-defined networking (SDN) platform
that unifies service automation with network
optimization. Now IP/optical network operators can
deliver on-demand network services cost-effectively
and with scalability.
The NSP provides operators with an efficient
way to define, provision and activate network
services across networks that can span multiple
layers (Layer 0 to Layer 3), services and
physical/virtual infrastructure, as well as
equipment from multiple vendors.
Product components
The NSP consists of three key modules:
Network Services Director (NSD): provides policy
based abstraction of IP/optical networks and
automates service provisioning.
Network Resources Controller (NRC): manages path
creation across networks and performs dynamic
network optimization
Template/Policy Provisioning Manager: customized
networking policies

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Network Service Platform: GUI overview

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The service portal interface
The graphical interface describes, through a web-based
service portal configured in 3D/2D Network topology, the
different slicing network layers (IP Services, IP/MPLS,
Optical L2, Optical ODU, Optical OCh, Physical) assigned
to different tenants, to Create/Modify/Delete services of
request in different layers.

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Map navigation
All the Network Elements are “virtualized”
The abstraction level of the representation is the key factor for the development of a multi-layer and multi-
technology network
Physical endpoints and available resources are the only elements to implement services on the network
A service can be overlayed on the physical topology view

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Map navigation
Different type of services can be
created/deleted:
L3 VPN
ELAN
ELINE
LAG
ODU
OCh

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Lab. platform
The NSP is designed to work with IP and Optical equipment, and is intended to work in a multi-layer and multi-
platform environment.
OMNISWITCH 6850e
HP server 2
HP server 1
7750 SR-7 service router 1
7750 SR-7 service router 2 1830 PSS-32 [SDN3]
1830 PSS-32 [SDN2]
FAN 32H
FAN 32H

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SDN proof of concept
Abstract
SERVICES
AUTOMATION
NETWORK
OPTIMIZATION
NETWORK
SERVICES
PLATFORM
Case I: Multi-Tenant Service Portal GUI. For simple and abstracted Policy based
provisioning of photonic Latency/Hops Optimized Service on ODU layer.
Case II: Elastic Bandwidth via Service Router LAG. Network adaptability to the
bandwidth variable demand. The SDN application monitors the LAG bandwidth
usage on the Service Routers and adds/removes a WDM service depending on
the LAG load.
Case III: Automatic creation of an optical L2 service. Optical ELINE via WDM and
Service Router Video distribution on ELAN with LAG protection.
Case IV: Bandwidth Scheduling of Optical ELINE. The Task Scheduling Manager is a
generic scheduling application that enables users to do operations with respect to
scheduling bandwidth modification requests/tasks on an existing service.

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SDN proof of concept: dynamic latency optimized L0 service
This function will be primarily focused on the network adaptability to create L0 services in ODU layer from
different client ports of different optical nodes, based on a cost function optimization.
The selectable objective specifies how a path will be chosen:
• Latency: path with least observed latency will be chosen
• Hops (Span): path with least hop count will be selected
• Cost: path with least measured cost will be selected

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SDN proof of concept: elastic bandwidth
An algorithm generate Ethernet traffic between two servers. It will try to maximize the throughput. After the
start of the traffic, only one OCh is available limiting the throughput to 10Gb/s on the correspondent optical line.
After a time the total throughput increases at 20Gb/s. NSP will detect that the threshold is crossed and will
create another OCh, on the correspondent optical line. When the additional OCh is created the throughput will
become 20Gb/s and update the LAG members. The bandwidth has increased and the LAG group will contains
now 2 members. On the optical ODU layer the second created connection is visible.

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SDN proof of concept: bandwidth on demand over L0 services
The application script provides a minimum
number of 1x10G guaranteed service on λ1.
The server traffic generator start to transmit
20Gb/s stream.
 After about T1 sec. a second 10G λ2 is
created because the HIGH threshold =
7.5Gb/s has been reached.
 After more T2 sec. the traffic generator
stops the streams transmission.
 The second 10G connection will be
removed when the LOW threshold = 5Gb/s
will be crossed.

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SDN proof of concept: bandwidth scheduling
In case of automatically BW modification, the user is allowed to change both the start date and the task
execution intervals. The user is able to view all of their current requests and the state of those requests
(Scheduled / Running / Disabled). The user can see a historical log of all executed tasks and their Success/Fail
status and results.

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SDN in advanced optical technologies
SDN application will become a crucial approach to the network definition also for the future implemented optical
technology improvements.
From fixed DWDM to SW-defined optical networking is the paradigm
toward the concept of “elastic networks”, to extend completely the
network virtualization into the optical domain.
SDN will be able to control and configure all the physical layer parameters of the network and the new features
applied to the evolution of the optical transmission:
Optical multilevel modulation, optical orthogonal frequency-division multiplexing (O-OFDM),
Bandwidth-variable wavelength selective switch (WSS)
Colorless (tunable) optical transponders
Multi-degree, directionless configurations
Distance-adaptive spectrum resource allocation
FlexGrid arrangement, coherent filtering, superchannel transmission

45. claudio.c.colombo@nokia.com