The OMEGA test-bed is used to test and validate the effectiveness and assess the performance of the concepts developed within the lab activities. The need for a test-bed raised after the promising results obtained in the NSF project "Differentiated Reliability (DiR) in Multi-Layer Optical Networks". The studied concepts were succesfully transferred to the test-bed and further extended thanks to the collaboration with CPqD research team.

The test-bed consists of 6 nodes connected to form a mesh (general) topology. Each node consists of a PC running Linux that is used to implement the control plane of the Optical Layer. The Optical Layer is emulated by a dedicated PC that will provide information about the status of the optical components. The interface between the PCs running the control plane and the PC emulating the Optical Layer will be realized using parallel ports. This interface will allow the control plane to both gather information regarding the status of the Optical Layer (e.g., fiber cut, signal degradation) and control the setup of the optical components (e.g., optical cross-connect). Connections between PCs running the control plane are realized using 100Mb/s Fast Ethernet interfaces.

Emulation of the Optical Layer enables to apply the implemented control plane functionalities to a wide range of emulated optical cross-connect technologies and platforms.

Additionally, the ongoing collaboration with the CPqD will enable to test part of the developed concepts on their optical test-bed.

The test-bed consists of PCs running Linux. Each PC acts as an OXC controller. Nodes are interconnected using 2 parallel networks:

• A number of point to point ethernet links. This is the real network topology. These links are used to carry the control and management information.
• A lab network. Each computer is connected through an ethernet switch to a debug, measurement, and visualization PC.

Each of the modules in the above figure are explained below:

• Hardware Setup and Maintenance
  This task consists of setting up the PCs, installing Linux with the appropriate options, e.g. real time extensions, maintaining the desired Linux functionalities, and managing the network(s) interconnecting the PCs.
   
• Custom Hardware Design
  This task consists of designing and building any required custom device to emulate optical circuits using electrical ethernet, e.g., designing and building delay elements to simulate various link lengths.
   
• Optical Layer Emulator
  This task consists of defining the interfaces between the OXC node controllers (Linux PCs) and the optical layer emulator. The interfaces will be implemented using the parallel port. The task should define and implement the Optical Layer Emulator functions and actions.
   
• Debug Capabilities, Measurements, and Visualization Interfaces
  This task consists of defining how debugging, measurement, and visualization messages are sent and built. Messages should be short and they are physically transmitted using the so called "lab" network.
   
• Scripting Tools
  This task consists of defining and implementing a scripting language to enable automatic generation and running of experiments on the test-bed.
   
• Protocol Design and Implementation
  This task consists of designing, simulating (using readily available or other custom built event-driven simulators), implementing, and testing various protocols to control and manage optical networks.