Ahmed Musa, John Medrano, Virgillio Gonzalez, Cecil Thomas University of Texas at El Paso Circuit Establishment in a Hybrid Optical-CDMA and WDM All- Optical Network Using the Flooding Mechanism Mehdi Shadaram University of Texas at San Antonio

*Introduction - A high demand on higher capacities ( Why all-optical network?) - Approaches to make the transmission medium has a scalable bandwidth (BW) capacity * Backbone network - Optical-Optical-Optical (OOO) - Optical-Electrical-Optical (OEO ) * Routing Benefits and Disadvantages *Proposed routing algorithm * Routing (Setup Optimal Lightpath) Steps *Routing Implementation Using Flooding Mechanism *Example *Conclusions Outline

Introduction A high demand on higher capacities because of  Multimedia services.  Video conferences  Internet.  Environmental remote sensing.  Medical imaging Approaches to make the transmission medium has a scalable bandwidth (BW) capacity  Install more fiber (costly)  Exploit the BW of existing fiber using higher data rates and multiplexing techniques such as  Wavelength Division Multiplexing (WDM). - Coarse WDM (# of Lambdas λ’s < 10) - Dense WDM (# of λ’s > 10)  Time Division Multiplexing (TDM).  Code Division Multiplexing (CDM).

Backbone network Optical – Electrical – Optical (OEO) Optical – Optical – Optical (OOO or Photonic NW) Photonic networks  Advantages –Solve the electronic equipment bottleneck –Exploit the existing network  Disadvantages - Photonic NW is a complex system ( a large number of different functions must cooperate for a network such as –transmission –Routing and Switching –Control and management –etc.

Routing Benefits  Support services such as connection on demand  Enriches the service level agreement (SLA) by supporting (Protection and Restoration).  Improves bandwidth (BW) efficiency and source utilization of the network.  Intractable problem (NP-Complete). Therefore, assumptions and heuristics are used to reduce the process complexity. Routing disadvantages  Upgrading the Network by :  Increase bit rate from 2.5 up to 160 Gb/s  #of wavelength up to 256  Narrowing the channel spacing  Is significantly affected by Routing Algorithm due to Physical impairments

Table 2: Optical Linear and Non-linear Impairments ClassImpairmentConstraint Linear Attenuation (Loss) Optical amplification implying OSNR degradation Chromatic dispersion (GVD) Compensation fiber or limit on the total length of fiber links Polarization-mode dispersion (PMD) Total length of fiber links Non- linear Self-phase modulation (SPM)NLP constraint Cross-phase modulation (XPM)NLP constraint Four – Wave Mixing (FWM)Negligible (per system design) Simulation Roman scattering (SRS) Modification of signal power (and thus NLP) Stimulated brillouin scattering (SBS) Negligible Noise Amplifier spontaneous emission (ASE) OSNR degradation (resulting in constraint on the number of fiber spans)

Routing algorithm flow diagram

Proposed routing algorithm –Used Optical CDM and WDM to label the optical signal –Takes into account the physical impairments existing in NW –Set up the lightpath based on calculating the cost of all possible paths from ingress to egress node. Routing (Setup Optimal Lightpath) Steps –First Step :- Calculate the fiber metrics. –Second Step :- Calculate switch metrics. –Third Step :- Apply Viterbi algorithm on each close loop from the source to destination to select the minimum metric.

Fiber metrics Where N is the normalization factor I/P Metric O/P Metric Link merits (L) :- Attenuation  Dispersion D Where, and  is a function of Attenuation  and Dispersion D

Wavelengths are selected based on ITU-T G.692 WDM grid Long band Long band Long band Long band Long band Long band Long band Long band Long band Long band Reference frequency Long band Long band Long band Long band Long band

Routing Implementation Using Flooding Mechanism (1) The forward signaling procedure (2) The backward signaling procedure. (3) The clearance procedure

Calculate Switch Metrics

Data start brusted through using the selected path (A B C)

Network Model and Bisectional Bandwidth

Network Characteristics and Switch Metrics Switch Metrics Matrix for 2 wavelengths x 2 codes Fiber Lengths : distance (Switch A, Switch B) = 30 km distance (Switch A, Switch C) = 20 km distance (Switch B, Switch C) = 25 km distance (Switch B, Switch D) = 15 km distance (Switch C, Switch D) = 20 km λ 1 C 1 λ 1 C 2 λ 2 C 1 λ 2 C 2 λ1C1λ1C2λ2C1λ2C2λ1C1λ1C2λ2C1λ2C2 λ 1 λ 2

Blocking probability of NW (2 wavelengths and 2 codes) at different traffic load

Blocking probability due to NW resources (2 wavelengths and 2 codes) at different traffic load

Conclusions  This algorithm help improving the NW Performance.  Flooding mechanism is used to set up the path (used in the control plane of the network independent of the information path.  Flooding mechanism is emulated in in the network manager.