Overview

OMNet++ based Dynamic Lightpath Establishment (ODLE) simulator is designed to allow parametric studies of various dynamic lightpath establishment protocols.

With a flexible design, different RWA schemes can be studied.

The simulator is developed to work with omnetpp 2.3 + Windows OS + VC6.0.

Simulator components

1. initial file, omnetpp.ini, see OMNet manual for details
2. NED files:
   1. simple.ned: all basic modules are defined in this ned file.
   2. OXC.ned: the OXC controller
   3. x.ned: the simulated network is defined in this NED file, the parameters such as delays (or link lengths) are also set in this x.ned
3. MSG files: to define packet formats used by signaling protocols:
   1. ProbPac: to probe the route information
   2. SetPac: to setup LPs
   3. RelPac: to release LPs
   4. NAckPac: to report about failures
4. header files: *.h
5. implementation files: *.cpp

Details - OXC controller design

This controller design is embedded at each OXC-network node

Figure 1: OXC controller design

Gen module

• Generate requests for LPs
• For each request, a ProbPac is generated and send to Routing module

Routing module

• This module is responsible for the routing task of the testing RWA
• Different routing scheme could be written and tried independently
• Upon receiving ProbPac from Gen, Routing module checks the desired destination d, then read the corresponding entry from the routing table, or run the routing algorithm, and update the route information to ProbPac
• Send ProbPac to MainProc

MainProc module

MainProc does some following tasks:

• Maintain a database about the configuration of the node (connected in/out links, wavelength converter pools and parameters...)
• Update ProbPac
• Forward packets to next hop
• Order to configure the node to setup/tear down LPs

PreProc module

• Detect the kind of packets that come from the control channel
• Forward packets to corresponding modules to further process

WA module

• This module is responsible for the wavelength assignment jobs
• Various WA schemes can be tested by modifying the implementation of this module, as one can do to the Routing module.

Set module

• This module receives the commands to generate SetPac from WA module
• SetPac bears all necessary information to setup the LP along the defined route
• SetPac is send to MainProc before leaving current OXC.

Mgt module

• Receive report packets from other modules, as indicated in the figure
• Log the statistic objects, performance metrics
• Write logged data to the vector file (during the simulation) and to the scalar file (when finishing the simulation)

Implementation

Figure 2: Example capture of the simulation under Tkenv, with 14-node NSFNet

The detail implementation at modules depends on what kind of protocols/algorithms/RWAs we study. Currently, we have finished the implementation for:

• Only single shortest path routing.
• Wavelength assignment schemes: Joint-Signaling-based (our proposal), and First-Fit.
• Lightpath establishment protocol without reservation phase.

Contacts

We are working on other protocols with various routing and wavelength assignment schemes. People who are interested in this research area and in our ODLE simulator are welcome to send a message to V.T. Nguyen
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