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Lecture 23 Part 1: Making a Case for Using IP to Design DWDM Networks

G. Birkan – SMU Student

E. Olinick – SMU Faculty

A. Ortynski – Nortel Networks

G. Spiride – Nortel Networks

Sponsors: ONR and Nortel Networks

Manuscript available on my web page

http://www.engr.smu.edu/~jlk/

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Design Software

OPNET Technologies, Inc.

RSoft, Inc.

VPI Systems

ARTIS Software Corp.

TelOptica, Inc.

(Heuristics – No LP No IP)

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Legitimate Concerns

Hard To Model Some Problems As LPs Or IPs (Polarization Mode Dispersion

Constraints)

Hard To Create Good Optimization Software

(Some Firms Want To Control All Software)

Computational Time Can Be Excessive

Convergence Can Be Slow

Professional Optimization Software Can Be Expensive

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Issues Faced By Network Designers

(Slide #1)Node-Arc Models – Can Not Control The Hop

Counts

Arc-Path Models – Not All Paths Are Available

Protection For Mesh Networks – Several Possibilities

Dedicated Protection(also called 1+1 protection)

P-Cycle Protection (Grover & Stamatelakis)

Shared Protection

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Issues Faced By Network Designers

(Slide #2)Uncertainty In The Demand Forecasts

(Nortel Networks Concerned About This)

{From The OR Literature}

Stochastic Programming (Linear)

Mean Value Model (Linear)

Worst Case Model (Linear)

Robust Optimization (Nonlinear)

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Our Investigation

We created AMPL models addressing all of these issues

and empirically tested our models.

Used AMPL/CPLEX

Used AlphaServer

667 MHz

4096 MB of RAM

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General Problem Description

Given1. Network Topology

2. Forecast Of Point-To-Point Traffic

Determine1. Routing For The Traffic

2. Equipment Configuration Required

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7

4

3

1

2

5

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AtlantaDallas

Chicago

Determine Where To Install Equipment To Light The Dark Fiber

New York

Los Angeles

San Francisco

Boston

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LTE LTE

LTE LTE

LTE LTE

… …

LTE LTE

LTE LTE

LTE LTE

… …

TE TE

TE TE

TE TE

… …

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A A

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LTE LTE

LTE LTE

LTE LTE

… …

LTE LTE

LTE LTE

LTE LTE

… …

TE TE

TE TE

TE TE

… …

R R

R R

R R

… …

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A A

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Basic Building Block for the WDM Network

Optical Amplifier

Regenerator

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4

2

1 3

Avoid Crossing Links

origin

destination

Working Path

Backup Path

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2859

2336

10

3018

2226 33

3 49

17 16 48

394764

2

13

14

65

8 21 6720

10 1542

9

625525

5024

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4 2760

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44 46 41

4034

58

5311

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54 7

63

612

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38 56

51

66

3531

2945

5

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Basic Test Problem (US network with average node degree of 3.15)

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Cycle Generation ModelGiven

G = [N,E]

origin (o)

destination (d)

integer k

Output

k – shortest paths (unique)

k - backup paths (not unique)

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Example

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31 2

6 5

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31 2

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4

8

31 2

64

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5

7

1 2

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