The Design of XML-Based Model and Experiment Description Languages for Network Simulation Andrew Hallagan Bucknell University Dept. of Computer Science Luiz Felipe Perrone, Advisor

3 General Network Types Hardwired, wireless and ad-hoc networks

3 General Network Types Hardwired, wireless and ad-hoc networks Nodes

3 General Network Types Hardwired, wireless and ad-hoc networks Channels

Communication Between Nodes Breaking a message up into packets.

Communication Between Nodes Breaking a message up into packets.

Communication Between Nodes Breaking a message up into packets.

Ways to Study a System Source: Averill M. Law, Simulation, Modeling & Analysis Physical model Experiment with the actual system Experiment with a model of the system System Mathematical model Analytical solution Simulation

Ways to Study a System Source: Averill M. Law, Simulation, Modeling & Analysis Physical model Experiment with the actual system Experiment with a model of the system System Mathematical model Analytical solution Simulation

A Simple Mobility Model The horizontal and vertical positions of the node are a function of SPEED and ANGLE, which are random variables distributed Normally and Uniformly, respectively. X-position = f(SPEED, ANGLE) Y-position = g(SPEED, ANGLE) SPEED ~ N(SPEED_MEAN, 3.0) ANGLE ~ U(0, ANGLE_BOUND) Model Inputs SPEED_MEAN ANGLE_BOUND

A Simple Mobility Model The horizontal and vertical positions of the node are a function of SPEED and ANGLE, which are random variables distributed Normally and Uniformly, respectively. X-position = f(SPEED, ANGLE) Y-position = g(SPEED, ANGLE) SPEED ~ N(SPEED_MEAN, 3.0) ANGLE ~ U(0, ANGLE_BOUND) Model Inputs SPEED_MEAN ANGLE_BOUND Model Description

Factor Levels ANGLE_BOUND SPEED_MEAN

Design Matrix ANGLE_BOUND SPEED_MEAN

Design Matrix ANGLE_BOUND SPEED_MEAN

Design Matrix ANGLE_BOUND SPEED_MEAN Experiment Description

Network Complexities Bandwidth, physical distance, network traffic, etc.

Network Complexities Bandwidth, physical distance, network traffic, etc.

Network Complexities Size.

Network Complexities Physical surroundings.

Recap Networks are complex. Modeling is difficult. Experimentation isn’t straight-forward. Mistakes in this process have led to credibility issues in network simulation.

Solution: Automation Automate the modeling and experiment design process for users. Automatically validate model descriptions. Automatically validate experiment descriptions. Automatically generate simulation scripts.

Motivation for Network Simulation Research Source: J. M. Brase and D. L. Brown, Modeling, Simulation and Analysis of Complex Networked Systems. White paper. “[The Department of Energy] must continue the development of next generation complex networked systems that are more secure, less brittle to unexpected events, and more controllable. For these emerging efforts to be successful, it is essential that a firm intellectual foundation be provided for understanding and simulating large-scale networks.”

SAFE Simulation Automation Framework for Experiments

High-level view of the SAFE architecture. My work is concerned with the Model Description and Experiment Description inputs to this framework (in the yellow boxes).

High-level view of the SAFE architecture. My work is concerned with the Model Description and Experiment Description inputs to this framework (in the yellow boxes).

An HTML “anchor” element. This piece of HTML is valid XML. It is an a tag with an attribute href. The value of the href attribute is a URL string and the content of the a tag is the “Link to Google” string. Link to Google Opening tag Attribute value Element content Closing tag

NEDL: Experiment Description

NEDL Functionality Provide ways to list experimental factors. ANGLE_BOUNDSPEED_MEAN

NEDL Functionality Provide ways to list associated level values for each factor. ANGLE_BOUND SPEED_MEAN

NEDL Functionality Provide ways to list associated level values for each factor. ANGLE_BOUND SPEED_MEAN “Use the values 3, 17, and 9.”

NEDL Functionality Provide ways to list associated level values for each factor. ANGLE_BOUND SPEED_MEAN “Use the same values already provided for another factor.”

NEDL Functionality Provide ways to list associated level values for each factor. ANGLE_BOUND SPEED_MEAN “Take multiples of 15 between 15 and 60.”

NEDL Functionality Provide ways to list associated level values for each factor. ANGLE_BOUND SPEED_MEAN “Use the values specified in my external file named ____”

NEDL Functionality Provide ways to “prune” design points from the experiment space. ANGLE_BOUND SPEED_MEAN

NEDL Functionality Provide ways to “prune” design points from the experiment space. ANGLE_BOUND SPEED_MEAN “Remove the specific design point where ANGLE_BOUND = 15 and SPEED_MEAN = 3.0.”

NEDL Functionality Provide ways to “prune” design points from the experiment space. ANGLE_BOUND SPEED_MEAN “Remove every third design point.”

NEDL Validation The NEDL validation module checks language semantics and ensures the experimenter has created a NEDL document that can be successfully parsed by SAFE.

NSTL: Model Description Flexible script templating

Creating an ns-3 script template. One can create an ns-3 script simply by removing certain hard- coded values and inserting special markers that correspond to the factors listed in a NEDL file. norm = ns3.RandomVariable(“Normal”, $SPEED_MEAN$, “3.0”) unif = ns3.RandomVariable(“Uniform”, 0, $ANGLE_BOUND$) node.setSpeed(norm) node.setAngle(unif)

Creating an ns-3 script template. Using the block element in NSTL, one can specify interchangeable code blocks to swap in an ns-3 script. Since two block elements are used, two scripts will be generated. norm = ns3.RandomVariable(“Normal”, $SPEED_MEAN$, “3.0”) unif = ns3.RandomVariable(“Uniform”, 0, $ANGLE_BOUND$) node.setSpeed(norm) node.setAngle(unif) node.setSpeed(17.0) node.setAngle(135)

Conclusions and Future Work

Thank you!