MULTIOPTI Research Program

Multicasting and groupcasting with physical layer constraints in metropolitan optical networks with mesh topologies

Software Tool

The MULTIOPTI software tool is designed for the dynamic simulation of all-optical, mesh Metropolitan Area Networks (MAN) that utilize the Wavelength Division Multiplexing (WDM) technology. In these networks, the signals do not undergo optical to electrical to optical (OEO) conversion at intermediate nodes. This simulation tool routes connections and assigns wavelengths (i.e. solves the RWA problem), as well as performs protection and grooming techniques for multicast (P2MP) and groupcast (MP2MP) connections taking into account physical layer constraints. The simulation follows a real life environment where traffic demands arrive and depart unexpectedly following probabilistic models. It integrates vertically the physical and logical layers by first calculating the path(s) from source to destination(s) in the logical layer, then calculating the Q-factor for that route (via a Qbudgeting approach), and using that information it decides whether a connection should be admitted to the network. This approach helps the network designer to calculate the impact of physical layer effects, such as non-linear effects, polarization effects, optical crosstalk, etc, in the design of a metropolitan optical network.

The MULTOPTI algorithms, simulation tool, and GUI are written in the widely used MATLAB�/Simulink� software environment while some of the underlying code is in C++. This version of MULTIOPTI has been enhanced to be compatible with the newest MATLAB� and Simulink� versions. It is also backward compatible and it can be run with former MATLAB� and Simulink� version 5. The MathWorks software runs on multiple platforms including Macintosh, UNIX and PCs. MULTIOPTI files have only been tested on a PC platform running Windows 7 and Windows XP.

A user of the simulation tool can define the network graph that will be used for the simulation, as well as the various networks parameters. These include the number of wavelengths, the type of network nodes, the physical characteristics of the network nodes and the network links. The user can also define the type of connections (multicast or groupcast) as well as the traffic characteristics. Depending on the type of connection, the user can run various routing scenarios. If the connections are multicast, the user can (a) run the routing and wavelength assignment algorithms taking the Qfactor into consideration and without �balancing� the tree to achieve better Q �results and (b) run the routing and wavelength assignment algorithms taking the Q-factor into consideration and �balancing� the multicast tree. Two different algorithms can be used to balance the tree. If the connections are groupcast, the user can (a) run the routing and wavelength assignment algorithms taking the Q-factor into consideration and utilizing the Light-Tree Heuristic, (b) run the routing and wavelength assignment algorithms taking �the Q-factor into consideration and utilizing the Light-Path Heuristic, and (c) run the routing and wavelength assignment algorithms taking the Q-factor into consideration and utilizing the Linear Light-Tree Heuristic. Similarly, the provisioning with protection techniques can be run with and without PLI constraints for all the dedicated and segment-based protection approaches specified in the description of WPs 4 and 7 and in Deliverables D1 and D3. Finally, the user has the option to run the multicast and groupcast grooming techniques specified in WPs 5 and 8 and in Deliverables 1 and 3. Various grooming subrates can also be specified in this case.

The main Operations of the Tool, performed through a different panel of the interface, are:

1. Creation and management of the network physical graph.

2. Creation and Management of the Network General Variables.

3. Creation and Management of the Network Traffic parameters.

4. Simulation of the optical Network RWA using multicast routes.

5. Simulation of the optical Network RWA using groupcast routes.

6. Simulation of the optical Network protection using multicast routes.

7. Simulation of the optical Network protection using groupcast routes.

8. Simulation of the optical Network grooming using multicast routes.

9. Simulation of the optical Network grooming using groupcast routes.

10. View and analyze Network simulation Results.

The Simulation Tool Features are as follows:

� Vertically integrates the physical and logical layer constraints for the simulation of MANs.

� Addresses both P2MP and MP2MP connections.

� Uses a Q-budgeting approach to easily and quickly approximate the physical layer constraints.

� Evaluates the network performance by calculating the number of connections that can be accepted to the network.

� Evaluates the network performance by calculating the number of connections that can be accepted to the network when protection is also required.

� Evaluates the network performance by calculating the number of connections that can be accepted to the network when traffic grooming is also taken into consideration.

� Evaluates a network design by allowing the user to each time modify the network parameters and compare the performance of each design.

� Utilizes an easy to use graphical user interface GUI with clear and self-explanatory views.

� Presents several views of the network (physical, logical, etc), and the established connections

Fig1: Physical Layer View

Fig. 2: Logical Layer View

Fig 3. Logical Layer View for a Single Connection

Fig. 4: Component Layer View