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Simple provisioning, complex
consolidation – An approach to
improve the efficiency of
provisioning oriented optical
networks
Tamás Kárász
Budapest University of Technology and Economics,
Department of Telecommunications
E-mail: [email protected]
1
Outline
• Motivations
• Fast provisioning in optical networks
• Network consolidation
• „Simple provisioning – complex consolidation”
approach
• Summary and Conclusions
2
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)
3
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
Practical Case
Theoretical Lower Bound
• Consolidation
Optical channel requests
Optical channel demands
arriving spread in time and
space are served one by
one by a distributed and
flexible network intelligence
applying on-line provisioning
algorithms.
Consolidation:
rearrangement
of already
arrived and
served requests
Low
assumed to be known in
advance (based on a
proper forecast) and an
optimal network
configuration is designed
to meet the demands.
High
Network Efficiency
4
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
Extension
- different objective functions can be used
of the network
• Extension of the network
- additional resources are designed
and installed to remove network
bottlenecks
Optional
Consolidation
Rearrangements to achieve
the optimal configuration
Provisioning
Network configuration
to serve dynamic requests
5
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)
6
When to consolidate?
• Predefined fixed periods
• Network state dependent adaptive periods
600
CONS(25)
resource of usage
500
CONS(50)
CONS(100)
400
CONS(200)
300
200
100
0
0
50
100
150
200
after number of arrivals
7
What to consolidate?
• Total: each already arrived and accommodated demands
• Selective: demands meeting specific rules
537
540
520
500
480
458
460
447
440
Provisioning
CONS(last_40)
CONS(200)
540
520
500
485
490
479
480
479
481
472
460
440
Share_20%
Share_30%
Share_40%
Share_50%
Share_60%
Share_80%
8
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
Provisioning
resource of usage
140
120
100
ILP
80
60
40
20
0
0
10
20
30
after number of arrivals
40
Permanent
working path and
wavelength
Permanent
working path
9
Simple provisioning, complex
consolidation
• Provisioning with dedicated path protection
• Consolidation with shared (backup) path protection
• Different consolidation strategies:
- fixed working path and wavelength
CONS(12)_shared_fixed
working & protection paths
CONS(12)_shared_fixed
working path & wl.
CONS(12)_shared_optimal
allocation
Provisioning without
consolidation
300
- fixed working and protection path
250
resource of usage
- optimal allocation
200
150
100
50
0
0
10
20
30
40
50
60
70
after number of arrivals
10
Simple provisioning, complex
consolidation
• Different frequently consolidation:
CONS(12)_shared_fixed
working path & wl.
CONS(24)_shared_fixed
working path & wl.
CONS(36)_shared_fixed
working path & wl.
250
resource of usage
200
150
100
50
0
0
10
20
30
40
50
60
70
after number of arrivals
11
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
12
Thank you for your attention!
13