1 PHYSICAL IMPAIRMENTS Maruthy Mentireddi Raghu Kalyan Anna

MOTIVATION IDEALISTIC: NO TRANSMISSION IMPAIRMENTS BEING CONSIDERED IN ROUTING DECISIONS. REALISTIC: TRANSMISSION IMPAIRMENTS ARE CONSIDERED IN ROUTING DECISIONS. IN ANY GIVEN SCENARIO TRANSMISSION IMPAIRMENTS PLAY A MAJOR ROLE IN ROUTING.

AGENDA TRANSMISSION IMPAIRMENTS IMPAIRMENTS BEING CONSIDERED METRICS AND NETWORK COMPONENTS DESCRIPTION HYBRID SIMULATION TECHNIQUE EVALUATION IMPAIRMENT AWARE RWA CONSTRAINT MODELS ILLUSTRATIVE EXAMPLES ACKNOWLEDGEMENT BIBLIOGRAPHY

TRANSMISSION IMPAIRMENTS LINEAR: –AMPLIFIER NOISE –PMD –CROSSTALK NON LINEAR –FOUR WAVE MIXING –SELF PHASE MODULATION –CROSS PHASE MODULATION –SCATTERING

IMPAIRMENTS BEING CONSIDERED OPTICAL SIGNAL - CROSSTALK AT CROSSCONNECT SWITCHES(XCS) - AMPLIFIED SPONTANEOUS EMISSION (ASE) NOISE AT INTERMEDIATE AMPLIFIERS Eg., EDFA’S CONSIDERATIONS FOR CONNECTION PROVISIONING OPTICAL SIGNAL-TO-NOISE RATIO (OSNR) POLARIZATION MODE DISPERSION (PMD)

INTRODUCTORY TERMS LIGHTPATH – AN ALL OPTICAL WDM CHANNEL BETWEEN ANY TWO NODES CONNECTION PROVISIONING – SETTING UP A LIGHTPATH FOR A CONNECTION REQUEST BY USING A ROUTING AND WAVELENGTH ASSIGNMENT (RWA) TECHNIQUE ROUTE – A PATH CONSISTING OF ONE OR MORE FIBER LINKS, FROM THE SOURCE TO THE DESTINATION.

TRAFFIC/ NETWORK PERFORMANCE: CALL BLOCKING PROBABILITY SIGNAL QUALITY: BIT ERROR RATE METRICS

BLOCKING PROBABILITY NUMBER OF BLOCKED CALLS P b = TOTAL NUMBER OF OFFERED CALLS

BIT ERROR RATE (BER) ACCUMULATION OF ASE NOISE AND CROSSTALK 1 SNR DEGRADATION INCREASE IN BER 2 1 AT EVERY NODE 2 AT DESTINATION

NETWORK COMPONENTS WRN – WAVELENGTH ROUTING NODE NETWORK COMPONENTS ALONG A LIGHTPATH IN A WAVELENGTH-ROUTED OPTICAL NETWORK RECEIVER ARRAY FIBER LINK CROSS CONNECT OPTICAL TAP TRANSMITTER ARRAY OPTICAL AMPLIFIER

NETWORK COMPONENTS (CONTD) COMPONENTS AND THEIR LOSS/GAIN PARAMETERS IN A WRN FIBER LOSS OPTICAL TAP LOSS INPUT AMPLIFIER GAIN OUTPUT AMPLIFIER GAIN DEMUX LOSS MUX LOSS SWITCH LOSS

NETWORK COMPONENTS (CONTD) ARCHITECTURE OF A N x N NONBLOCKING SPACE SWITCH USED IN OUR MODEL

SIMULATION MODEL HYBRID SIMULATION TECHNIQUE

TRAFFIC VARIATION CROSSTALK, GAIN, ASE NOISE AFFECTS BER ESTIMATE ONLINE BER ESTIMATE

CALL ADMISSION: - MINIMUM BER - BER THRESHOLD (SAY ) CALL ADMISSION

ONLINE BER EVALUATION

BER MODEL LIGHTWAVE RECEIVED E R (t) = Acos(2ΠV i t + Φ(t)) + E xt (t) + E ase (t) PHOTOCURRENT GENERATED i p (t) = R ƛ (E R 2 (t)) + i sh (t) + i th (t) BER MINIMIZATION σ 0 I s1 I TH = σ 0 + σ 1

ILLUSTRATIVE EXAMPLES CALLS AT THE INSTANT OF SIMULATION SNAPSHOT IN A BIDIRECTIONAL RING NETWORK

ILLUSTRATIVE EXAMPLES (CONTD) PROGRESS OF TAGGED CALL IN A BIRECTIONAL RING NETWORK

ILLUSTRATIVE EXAMPLES (CONTD) A MESH NETWORK

ILLUSTRATIVE EXAMPLES (CONTD) MESH NETWORK - BLOCKING PROBABILITY Vs LOAD FIRST FIT BER RANDOM BER INCREASED CROSSTALK INADEQUATE SATURATION GAIN IDEAL CASE FIRST FIT IDEAL RANDOM IDEAL

IMPLICATIONS REALISTIC BER: MORE ACCURATE MEASURE OF PERFORMANCE THAN IDEAL CASE FIRST FIT BETTER THAN RANDOM FIT (IDEAL) RANDOM FIT BETTER THAN FIRST FIT (REALISTIC)

IMPAIRMENT AWARE RWA WHY IRWA? AUTOMATICALLY PROVISION A SIGNAL-QUALITY- GUARANTEED LIGHTPATH FOR A CONNECTION REQUEST

IRWA (CONTD) LIGHTPATH ASSIGNMENT BASED ON IRWA:  LIGHTPATH COMPUTATION  LIGHTPATH VERIFICATION NETWORK-RESOURCE BLOCKING : NO AVAILABLE ROUTE OR WAVELENGTH PHYSICAL LAYER BLOCKING SIGNAL-QUALITY REQUIREMENTS

IRWA – INTEGRATED MODEL

NETWORK LAYER MODULE IMPAIRMENT AWARE BEST PATH ALGORITHM(IABP) IMPAIRMENT AWARE FIRST FIT ALGORITHM(IAFF) - WILL RANDOM-ROUTING PERFORM BETTER ?

IABP – INTEGRATED MODEL INPUTS - NETWORK STATE - CONNECTION REQUEST OUTPUTS NETWORK LAYER - PATH, WAVELENGTH PHYSICAL LAYER – LIGHTPATH SIGNAL QUALITY ALGORITHM - PATH COMPUTATION - PATH OPTIMIZATION / WAVELENGTH ASSIGNMENT - SIGNAL QUALITY ESTIMATION - PATH SETUP - NETWORK STATE UPDATE

PHYSICAL LAYER MODULE OSNR AND PMD CONSTRAINTS PMD CONSTRAINT MODEL – TRANSMISSION LENGTH LIMITATION OSNR CONSTRAINT MODEL – Q FACTOR AS INTERMEDIATE

LIGHTPATH ARCHITECTURE AMPLIFICATION SPAN STANDARD SINGLE MODE FIBER DISPERSION COMPENSATING FIBER

OSNR ESTIMATION

PROPOSED IRWA’s CHARCTERISTICS CONNECTION ADMISSION METRICS: FREE RESOURCES AND SIGNAL QUALITY AUTO-PROVISIONING IMPAIRMENT AWARENESS - PMD TOLERATION - PRE-ESTIMATED OSNR ALGORITHM COMPARISION SCHEMES - NETWORK MODEL: IDEAL AND REALISTIC IDEAL: TRADITIONAL RWA (TBP OR TFF) – A REALISTIC: TRADITIONAL RWA (TBP OR TFF) – B, IRWA (IRWA OR IAFF) – C

BEST-PATH ALGORITHMS ILLUSTRATIVE EXAMPLES TBP - REAL IABP - REAL TBP - IDEAL

FIRST-FIT ALGORITHMS ILLUSTRATIVE EXAMPLES (CONTD) TFF - REAL IAFF - REAL TFF - IDEAL

ILLUSTRATIVE EXAMPLES (CONTD) BEST-PATH ALGORITHMS EMPLOYING EDFA TBP - REAL IABP - REAL TBP - IDEAL

ILLUSTRATIVE EXAMPLES (CONTD) FIRST-FIT ALGORITHMS EMPLOYING EDFA TFF - REAL IAFF - REAL TFF - IDEAL

ILLUSTRATIVE EXAMPLES (CONTD) EFFECT ON DATA RATE AVERAGE NUMBER OF TRIALS FOR SIGNAL-QUALITY ESTIMATION PER CALL IABP IAFF

ILLUSTRATIVE EXAMPLES (CONTD) EFFECT ON DATA RATE EFFECT OF CHANNEL BIT RATE ON ALGORITHMS IN A REALISTIC NETWORK

IMPLICATIONS BIT RATE INCREASE MAKES IMPAIRMENTS DOMINANT HIGH DATA RATE -> HIGH OSNR IS REQUIRED HIGH DATA RATE-> PMD LIMITING FACTOR

ACKNOWLEDGEMENT FIGURES AND EQUATIONS HAVE BEEN ADOPTED FROM: 1. Impact of transmission impairments on the teletraffic performance of wavelength-routed optical networks, B. Ramamurthy, D. Datta, H. Feng, J. P. Heritage, and B. Mukherjee 2. Connection provisioning with transmission impairment consideration in optical WDM networks with high-speed channels, Yurong Huang Heritage, J.P. Mukherjee, B.,

BIBLIOGRAPHY Issues for routing in the optical layer, J. Strand, A. L. Chiu, and R. Tkach Optical components for WDM lightwave networks, Borella, M.S. Jue, J.P. Banerjee, D. Ramamurthy, B. Mukherjee, B. Impact of transmission impairments on the teletraffic performance of wavelength-routed optical networks, B. Ramamurthy, D. Datta, H. Feng, J. P. Heritage, and B. Mukherjee Connection provisioning with transmission impairment consideration in optical WDM networks with high-speed channels, Yurong Huang Heritage, J.P. Mukherjee, B.,

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