commtech talks: elastic optical devices for software defined optical networks

1 © Nokia 2016 1 © Nokia 2016

Elastic Optical Devices pave the way for Software Defined Optical Networks

A. Morea and C. Colombo

CommeTechSpeech, PoliMi, 20-01-2016

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 © 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 © 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 © 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 © 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

/M

ap

per

RF Amp

RF Amp

RF Amp

RF Amp

28Gbit/s

28Gbit/s

28Gbit/s

28Gbit/s p /2

Local oscillator

Client

Deci

sion

Carr

ier Fre

quency

est

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on

Carr

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on

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• 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 © Nokia 2016

Coherent transmission meets capacity requirements

25Gbps 50Gbps 75Gbps 100Gbps > 100Gbps

1

2.2

2.5

0.2

1.4

BPSK1bit/symb

PDM-BSPK2 bit/symb

PS-QPSK3bit/symb

PDM-QPSK4bit/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 © 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 © 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 © 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 © 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 © 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 © Nokia 2016 13

Position



Network upgrades[8],


0

2000

4000

6000

T0 T1 T2 T3 T4

Time

Tota

l Co

st (

a.u

.)

MLR0

2000

4000

6000

T0 T1 T2 T3 T4

Time

Elastic 100G only

14 © Nokia 2016 14

Position




Asymmetric traffic[9],


15 © Nokia 2016 15

Position





Dynamic traffic demands (hold-time and/or time-varying)


0

1

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5

40 50 60 70 80

Network load (Erlang)

Po

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w/ current protocol

w/ proposed protocol

(c)

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40 50 60 70 80


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w/ current protocol


(c)

16 © Nokia 2016 16

Position





Dynamic traffic demands (hold-time and/or time-varying)

Network aging[11]


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 © 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 © 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 © 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 © Nokia 2016

Any questions ?

22 © Nokia 2016

Stage positions for working on elastic optical network concepts are open in our team (network dimensioning planning tool)

Contact point: [email protected]

<Change information classification in footer>

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[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


http://www3.alcatel-lucent.com/features/100g_era/



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


https://www.alcatel-lucent.com/innovation/400g-pse





25 © Nokia 2016

Elastic Optical Devices pave the way for Software Defined Optical Networks

[email protected]

January, 2016

26 © Nokia 2016

26 © Nokia 2016

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

27 © Nokia 2016

27 © Nokia 2016

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

28 © Nokia 2016

28 © Nokia 2016

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.

29 © Nokia 2016

29 © Nokia 2016

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

30 © Nokia 2016

30 © Nokia 2016

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)

31 © Nokia 2016

31 © Nokia 2016

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.

33 © Nokia 2016

33 © Nokia 2016

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

35 © Nokia 2016

35 © Nokia 2016

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.

36 © Nokia 2016

36 © Nokia 2016

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

37 © Nokia 2016

37 © Nokia 2016

Map navigation

Different type of services can be created/deleted:

L3 VPN ELAN ELINE LAG ODU OCh

38 © Nokia 2016

38 © Nokia 2016

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

39 © Nokia 2016

39 © Nokia 2016

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.

40 © Nokia 2016

40 © Nokia 2016

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

41 © Nokia 2016

41 © Nokia 2016

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.

42 © Nokia 2016

42 © Nokia 2016

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.

43 © Nokia 2016

43 © Nokia 2016

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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44 © Nokia 2016

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

[email protected]

commtech talks: elastic optical devices for software defined optical networks

Engineering