High-Availability%20Network%20Architectures%20(HAVANA):%20Comparative%20Study%20of%20Fully%20Pre-Cross-Connected%20Protection%20Architectures%20for%20Transparent%20Optical%20Networks%20Contact:%20grover@trlabs.ca - PowerPoint PPT Presentation

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High-Availability%20Network%20Architectures%20(HAVANA):%20Comparative%20Study%20of%20Fully%20Pre-Cross-Connected%20Protection%20Architectures%20for%20Transparent%20Optical%20Networks%20Contact:%20grover@trlabs.ca

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High-Availability Network Architectures (HAVANA): Comparative Study of Fully Pre-Cross-Connected Protection Architectures for Transparent Optical Networks – PowerPoint PPT presentation

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Title: High-Availability%20Network%20Architectures%20(HAVANA):%20Comparative%20Study%20of%20Fully%20Pre-Cross-Connected%20Protection%20Architectures%20for%20Transparent%20Optical%20Networks%20Contact:%20grover@trlabs.ca


1
High-Availability Network Architectures
(HAVANA)Comparative Study of Fully
Pre-Cross-Connected Protection Architectures for
Transparent Optical NetworksContact
grover_at_trlabs.ca
A. Grue, W. D. Grover, J. Doucette, B. Forst, D.
Onguetou, D. Baloukov TRLabs (Network Systems
Group) 7th Floor, 9107 116 Street Edmonton,
Alberta, Canada T6G 2V4
M. Clouqueur, D. Schupke Nokia Siemens
Networks (Network Control-Plane and
Transport) Otto-Hahn-Ring 6 81730 Munich, Germany
2
Pre-Cross-Connection A Design Constraint
  • Non-Pre-Cross-Connected
  • Shared pool of spare capacity
  • Backup paths cross-connected at failure time
  • Examples SBPP, span-restorable mesh
  • Pre-Cross-Connected
  • Cross-connections for backup paths formed in
    advance of failure
  • Resulting chains of pre-cross-connected capacity
    coalesce into protection structures
  • Examples BLSR, p-cycles

x2
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11
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12
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x3
3
Outline
  • Architectures
  • Project Overview
  • Methods and Results
  • Conclusions

4
p-Cycles
Straddling span
On-cycle span
5
Failure Independent Path Protecting p-Cycles
Straddling path
On-cycle path
6
PXTs (Pre-Cross-Connected Trails)
Understanding PXTs Behave like FIPP cycles,
only the structures are not closed
As a consequence, they are not able to provide
two protection paths for failed working paths
7
DSP (Demand-Wise Shared Protection)
Understanding DSP It is essentially 1N APS over
N1 disjoint routes between end nodes
8
Outline
  • Architectures
  • Project Overview
  • Methods and Results
  • Conclusions

9
Project HAVANA Outline/Objectives
  • Objective To characterize and compare many
    different pre-cross-connected protection
    architectures on a single network, under
    real-world constraints to network intelligence
    and flexibility
  • Project Phases
  • Basic architecture design (capacity for single
    span failure restorability)
  • Dual failure analysis of basic designs
  • Wavelength assignment feasibility and methods
  • Optical path length constraints analysis and
    enhancement
  • Outputs
  • A set of best feasible network designs
  • Theoretical insights into architectural
    properties
  • Design methods and insights

10
Outline
  • Architectures
  • Project Overview
  • Methods and Results
  • Basic architecture design
  • Conclusions

11
TestSet0 Network
12
Working Routing Constraints
  • Models for FIPP, PXTs, and p-cycles are SCP
    (spare capacity placement) only working routing
    is static
  • Both FIPP and PXTs require a working routing such
    that at least one path, disjoint from the working
    path, exists between the end nodes


13
Results Spare Capacity Redundancy
  • p-Cycles are the most capacity efficient
  • DSP has capacity efficiencies just slightly lower
    than that of 11 APS

14
Outline
  • Architectures
  • Project Overview
  • Methods and Results
  • Basic architecture design
  • Dual failures
  • Conclusions

15
Dual Failures Network Intelligence
  • The response to a first failure cannot change as
    a result of a second failure failure responses
    are independent

16
Results Dual Failures
100
of all failed paths restored over all dual
failure scenarios
DSP 85
PXTs and p-cycles 66
FIPP p-cycles 50
17
Outline
  • Architectures
  • Project Overview
  • Methods and Results
  • Basic architecture design
  • Dual failures
  • Wavelength assignment
  • Conclusions

18
Wavelength Assignment in p-Cycles
  • p-Cycles require either wavelength conversion or
    at least 2 fibres on every span in order to
    support wavelength continuity

Different wavelengths for 2 different working
paths
Wavelength conversion required for break-in
19
Results Wavelength Assignment
  • Wavelengths are allocated to the network in bands
    of 20
  • 40-wavelength (2 bands) assignment found for all
    architectures
  • 20-wavelength (1 band) assignments found for
  • PXTs (modified SCP model)
  • FIPP p-cycles (JCP model necessary)
  • Not found for
  • DSP (impossible)
  • p-cycles (perhaps possible using JCP?)

20
Outline
  • Architectures
  • Project Overview
  • Methods and Results
  • Basic architecture design
  • Dual failures
  • Wavelength assignment
  • Optical path lengths
  • Conclusions

21
Results Optical Path Lengths
  • Only DSP design satisfied reach constraints with
    the original design
  • PXTs and FIPP p-cycle designs easily found by
    modifying the pre-processing step
  • Compliant p-cycle design found by using a new ILP
    model altogether

22
Outline
  • Architectures
  • Project Overview
  • Methods and Results
  • Conclusions

23
Conclusions
  • Architecture Scorecard

Dual Failure Restorability
Wavelength Assignment
Optical Reach
Cost of Design
PXTs
p-Cycles
DSP
DSP
Best
FIPP p-Cycles, PXTs
FIPP p-Cycles, PXTs
PXTs, p-Cycles
FIPP p-Cycles
DSP, p-Cycles
p-Cycles
DSP
Worst
FIPP p-Cycles
24
To Find Out More
  • References on PXTs, FIPP p-Cycles, DSP (listed in
    paper)
  • A. Kodian, W.D. Grover, Failure Independent
    Path-Protecting p-Cycles Efficient and Simple
    Fully Pre-connected Optical-path Protection,
    IEEE Journal of Lightwave Technology, vol. 23,
    no.10, October 2005.
  • T. Y. Chow, F. Chudak, A. M. Ffrench. Fast
    Optical Layer Mesh Protection Using
    Pre-Cross-Connected Trails, IEEE/ACM Trans.
    Networking, vol. 12, no. 3, pp. 539-547, June
    2004.
  • Koster, A. Zymolka, M. Jager, R. Hulsermann,
    Demand-wise Shared Protection for Meshed Optical
    Networks, Journal of Network and Systems
    Management, vol. 13, no. 1, pp. 35-55, March
    2005.
  • A. Grue, W.D. Grover, Characterization of
    pre-cross-connected trails for optical mesh
    network protection, OSA Journal of Optical
    Networking, May 2006, pp.493-508

25
High-Availability Network Architectures
(HAVANA)Comparative Study of Fully
Pre-Cross-Connected Protection Architectures for
Transparent Optical NetworksContact
grover_at_trlabs.ca
A. Grue, W. D. Grover, J. Doucette, B. Forst, D.
Onguetou, D. Baloukov TRLabs (Network Systems
Group) 7th Floor, 9107 116 Street Edmonton,
Alberta, Canada T6G 2V4
M. Clouqueur, D. Schupke Nokia Siemens
Networks (Network Control-Plane and
Transport) Otto-Hahn-Ring 6 81730 Munich, Germany
26
Some Insights
  • DSP
  • - Why isn't it more efficient than it is ? (Turns
    out almost identical to 11 APS)
  • - Amenability to exact design with ILP (design
    ease)
  • PXTs
  • High design and conceptual complexity
  • Good flexibility for wavelength assignment,
    optical path length constraints
  • p-Cycles
  • Surprise that plain p-Cycles still have the best
    spare capacity efficiency
  • Not inherently end-to-end path-protecting
  • Optical Reach design control developed
  • FIPP p-Cycles
  • Offer a simple end-to-end protected path
    tunnel operating paradigm
  • Exact ILP design possible, heuristics under
    development

27
Project HAVANA Ongoing Work
  1. Node Failure restorability analysis (and enhanced
    design)
  2. Detailed minimum-cost mapping of designs into
    nodal equipment models
  3. Costs associated with design for 100 node
    failure restorability
  4. Implications / feasibility of same wavelength
    protection options in each architecture
  5. Finding a good heuristic for FIPP p-Cycle design.
  6. Design for 100 R2 and/or to support multi-QoP
    classes involving an ultra high availability
    (R21) priority service.

28
p-Trees / p-Cycles Computationally Distinct
p-Cycles Span p-Trees
PXTs/FIPP p-Cycles Path p-Trees
29
The Z Case in FIPP p-Cycle Design
  • Protection paths are pre-connected, but the
    protection path to be used will depend on the
    failure scenario
  • For the purpose of this study, the network was
    deemed not intelligent enough to handle this
    degree of failure dependency


30
The Z Case in FIPP p-Cycle Design
  • Protection paths are pre-connected, but the
    protection path to be used will depend on the
    failure scenario
  • For the purpose of this study, the network was
    deemed not intelligent enough to handle this
    degree of failure dependency


31
Optical Path Lengths for p-Cycles
  • In a path-protecting architecture, protection
    paths are completely substituted for working
    paths during failure, meaning that the lengths of
    the restored state paths are not in question
  • In a span-protecting architecture (p-Cycles, span
    p-Trees), protection paths are only substituted
    for the failed span, which may be used by many
    working paths with different lengths
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