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Simple provisioning, complex consolidation – An approach to

improve the efficiency of provisioning oriented optical

networks

Tamás KárászBudapest University of Technology and Economics,

Department of TelecommunicationsE-mail: karasz@hit.bme.hu

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Outline

• Motivations

• Fast provisioning in optical networks

• Network consolidation

• „Simple provisioning – complex consolidation”

approach

• Summary and Conclusions

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Motivations

• Paradigm changes in the transport network development:- POTS era: the design and dimensioning were based on traffic forecasts (dominant voice traffic, models, measurements)- Internet era: the permanently increasing data traffic becomes the largest traffic component → the modelling and forecasting of services and traffic growth are significantly more difficult → intelligent configuration flexibility or inefficient capacity over-dimensioning are needed → Traffic Engineering (IP layer)

→ fast provisioning (optical layer)

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Fast provisioning in optical networks

• Clients generate permanent, long lasting optical channel requests spread in time and space• Distributed signalling and switching intelligence in the optical network nodes• Routing and wavelength allocation (RWA) problem is solved on-line• Suboptimal decisions• Consolidation

Network Efficiency

Low High

Optical channel requestsarriving spread in time and space are served one by one by a distributed and flexible network intelligence applying on-line provisioning algorithms.

Optical channel demandsassumed to be known in advance (based on a proper forecast) and an optimal network configuration is designed to meet the demands.

Practical Case Theoretical Lower Bound

Consolidation:rearrangement of already arrived and served requests

Network Efficiency

Low High

Optical channel requestsarriving spread in time and space are served one by one by a distributed and flexible network intelligence applying on-line provisioning algorithms.

Optical channel demandsassumed to be known in advance (based on a proper forecast) and an optimal network configuration is designed to meet the demands.

Practical Case Theoretical Lower Bound

Consolidation:rearrangement of already arrived and served requests

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Provisioning Oriented Optical Networks

Three-phase lifecycle:• Provisioning:

- to set up optical lightpaths performing on-line decisions and configuration actions → suboptimal decisions- the decisions cover both path selection and wavelength assignment- different resilience options can be specified for the optical channel requests

• Consolidation:- reconfiguration decisions based on the knowledge of a certain group of optical channel requests is definitely more efficient - sequence of reconfiguration actions is needed to set up the obtained optimal network state- different objective functions can be used

• Extension of the network- additional resources are designedand installed to remove networkbottlenecks

Extension of the network

Provisioning Network configuration

to serve dynamic requests

Consolidation Rearrangements to achieve the optimal configuration

Optional

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Network consolidation

Some questions to be answered:• when (how frequently)

• what (which subset of accommodated demands)

• how (which network parameters to modify)

• limitations (operational cost, service risk, live traffic)

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When to consolidate?

• Predefined fixed periods

• Network state dependent adaptive periods

0

100

200

300

400

500

600

0 50 100 150 200

after number of arrivals

reso

urce

of

usag

e

CONS(25)

CONS(50)

CONS(100)

CONS(200)

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What to consolidate?

• Total: each already arrived and accommodated demands

• Selective: demands meeting specific rules

485479 481

490

472

479

440

460

480

500

520

540

Share_20% Share_30% Share_40% Share_50% Share_60% Share_80%

537

458

447

440

460

480

500

520

540

Provis ioning CONS(las t_40) CONS(200)

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How to consolidate?

• Total: re-design and re-configure demand accommodations (working and backup path and wavelength)

• Selective: e.g. re-design and re-configure backup path and wavelength only

• Architectural: provisioning parameter, resilience architecture

0

20

40

60

80

100

120

140

0 10 20 30 40

after number of arrivals

reso

urce

of u

sage

Provisioning

ILP

Permanentworking path andwavelengthPermanentworking path

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Simple provisioning, complex consolidation

• Provisioning with dedicated path protection

• Consolidation with shared (backup) path protection

• Different consolidation strategies:- fixed working path and wavelength

- fixed working and protection path

- optimal allocation

0

50

100

150

200

250

300

0 10 20 30 40 50 60 70

after number of arrivals

reso

urce

of u

sage

CONS(12)_shared_fixedworking & protection pathsCONS(12)_shared_fixedworking path & wl.CONS(12)_shared_optimalallocationProvisioning withoutconsolidation

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Simple provisioning, complex consolidation

• Different frequently consolidation:

0

50

100

150

200

250

0 10 20 30 40 50 60 70

after number of arrivals

reso

urce

of u

sage

CONS(12)_shared_fixedworking path & wl.CONS(24)_shared_fixedworking path & wl.CONS(36)_shared_fixedworking path & wl.

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Summary and Conclusions

• Three phase lifecycle for Provisioning Oriented Optical Network Design

• When, what, how to consolidate

• For higher efficiency the consolidation can be extended to a higher architectural level of networks

• „Simple provisioning – complex consolidation” approach

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Thank you for your attention!