A Ptolemy Based Optical Network Simulator Hasan I. Saleheen Science & Technology Division Corning Incorporated Overview Why simulate optical networks? Desired features of an optical network simulator Why use Ptolemy? The network simulator Examples of network simulation Some comments about Ptolemy Classic Conclusion 2
Why Simulate Optical Networks? Network Analysis Power budget Impairment analysis Crosstalk Noise Filter effect Performance evaluation BER Q Architecture evaluation Device Simulation Spectral analysis Sensitivity analysis 3 Desired Features of an Optical Network Simulator GUI Flexible Data Structure Hierarchical Modeling Automated Scheduling 4
Why Use Ptolemy? (Why need a software framework?) Open source code No need to start from scratch Easy to customize Lots of built-in modules provides numerous functionality (signal source, visualization..) Flexible data structure allows customized messaging between network elements Hierarchical modeling capability extremely useful for complex network module development Built-in GUI Automated scheduling Open discussion forum Widely accepted across industry 5 The Network Simulator Collection of modules Device Simple (Demux/Mux, Switch, Amplifier, VOA) Complex (WADM, WSXC) Auxiliary Visualization QoS Histogram Ptolemy integration develop back-end codes (device models) develop front-end codes (.pl files/gui code) for network elements compile and link with Ptolemy 6
The Network Simulator Functionality Impairment analysis Crosstalk Amplifier noise Performance analysis Q BER OSNR Performance indicator Worst crosstalk level Histogram of crosstalk 7 Network Simulation: Ring Network Backbone Network EN 50 km 50 km 50 km 50 km 100 km ADM #1 40 km Banded add- 0 dbm @ ADM1 and -8 dbm @ ADM2 40 km Device Parameter- Mux/Demux: Wavelength dependent Switch: Wavelength dependent Fiber attenuation: -0.2 db/km gain and noise figure: Add-drop Node Structure from experimental data ADM #2 8 Channels- 1547.82-1553.45 nm Input power- 0, 0, 0, 0, -8, -8, -8, -8 dbm Each ADM1 & ADM2 add-drops four channels and EN add-drops all eight channels channels 5-8 @ ADM1, 1-4 @ ADM2 and 1-8 @ EN In Add 8 DeMux Add-Drop Switch Mux #1 Add Drop #8 Out Drop
Frame 001 10N ov200 0 Frame 001 22F eb2001 Ring Network Simulation: Results Histogram of crosstalk levels at the drop port of EN, ADM1 and ADM2 B in B in B in C ou n t Crosstalk Level (dbm) OSNR ( db) 90 80 70 60 50 OSNR at output ports of EN, ADM1 and ADM2 C o u n t E N ADM1 ADM2 Crosstalk Level (dbm) Q Q values at drop ports of EN, ADM1 and ADM2 9 8 7 6 C ou n t Crosstalk Level (dbm) E N 2. 5 G b/s ADM1 2. 5 G b/ s ADM2 2. 5 G b/ s EN ADM #1 ADM #2 40 30 5 9 20 1547 1548 1 549 1550 1551 155 2 1553 1554 W av elength (nm) 4 1547 1548 1 549 1550 1551 155 2 1553 1554 W av elength (nm) Network Simulation: Interconnected Ring Network 10 EN = Egress Node AN = Access Node ADM = Add Drop Multiplexer Backbone Network EN 40 km 40 km Input/Added power -2 dbm 8 Channels (1547.82-1553.45 nm) AN#1 - Channels 1-4 crossed over to ring1 AN#2 - Channels 5-8 crossed over to ring2 ADM#1/ADM#3 - All channels add-drop ADM#2 - Channels 1-4 pass, channels 5-8 add-drop ADM#4 - Channels 5-8 add-drop, channels 1-4 pass Feeder Ring ADM#4 AN#2 AN#1 Distribution Ring #2 ADM#1 Distribution Ring #1 40 km ADM#3 ADM#2
Fram e001 25 Feb20 00 Fram e001 5A pr2000 Fram e001 1Jun 2000 Frame00 1 1Jun 2000 Interconnected Ring Network Simulation: Results ASE Noise at ADM Drop Ports ASE Noise at ADM Output Ports 0 0 ASE Noise (dbm/ghz) -20-40 -60-80 -100-120 ADM #1 ADM #2 ADM #3 ADM #4 ASE Noise (dbm/ghz) -10-20 -30-40 -50-60 -70-80 -90-100 ADM#1 ADM#2 ADM#3 ADM#4 11 Output Power(dBm), Worst Crosstalk (dbm) -140-160 1547 1548 1549 1550 1551 1552 1553 1554 Wavelength ( nm) Output Power and Worst Crosstalk at ADM Drop Ports 0-10 -20-30 -40-50 -60-70 1547 1548 1549 1550 1551 1552 1553 1554 Wavelength (nm) ADM #1, X ADM #2, X ADM #3, X ADM #4, X ADM #1, O ADM #2, O ADM #3, O ADM #4, O OutputPower (dbm), Worst Crosstalk (dbm) -110-120 -130 1547 1548 1549 1550 1551 1552 1553 1554 Wavelength (nm) Output Power and Worst Crosstalk at ADM Output Ports -10-20 -30-40 -50-60 -70-80 -90 1547 1548 1549 1550 1551 1552 1553 1554 Wavelength ( nm) A DM#1,O A DM#1,X A DM#2,O A DM#2,X A DM#3,O A DM#3,X A DM#4,O A DM#4,X Some Comments About Ptolemy Very useful for optical network simulation development provides all necessary features framework architecture matches with application s/w structure Highly active and very helpful user community useful for newcomers fruitful exchange of information Long learning curve Customized application development not easy no suitable debugger Ptolemy classic GUI not very user-friendly users do not like memorizing function keys window object manipulation is not intuitive (not drag-n-drop!) Non-graceful degradation 12
Conclusions Ptolemy provided the near ideal platform for optical network simulation development The Ptolemy open source codes substantially simplified customized network element development Numerous built-in Ptolemy modules provided the functionality of most commonly performed functions. This significantly reduced the development time The Ptolemy-based optical network simulator calculates major impairments in optical networks 13 Conclusions The network simulator enables performance evaluation of different network architectures As an additional feature, the network simulator can also calculate impairments of standalone optical network components Developing customized application on Ptolemy is non-trivial For the network simulator, a more user-friendly GUI could make the tool easier to operate 14