GSoC March 2009 1

Generally Successful owing-to Communication:ns-3 Experiences with GSoC

Craig DowellUniversity of Washington

Google SoC InfosessionMarch 5, 2009

GSoC March 2009 2

Outline

• A quick overview of ns-3

• Our Experiences with GSoC– Our Process– Lessons Learned

GSoC March 2009 3

What is ns-3?

• Open-Source Discrete-Event Network Simulator

• Allows Simulation of Internet Systems

• Integration with Testbeds and Virtual Machines

GSoC March 2009 4

What is ns-3?

A Simulated ns-3 Node is a bare computer to which simulated applications, stacks, and NICs are added

ApplicationApplication

Application

GSoC March 2009 5

What is ns-3?

Ns-3 Simulates Complex Network Topologies in Software

GSoC March 2009 6

What is ns-3?

Ns-3 Connects “Real” Software Through Simulated Networks

virtualmachine ns-3

virtualmachine

real machine

GSoC March 2009 7

Example: Emulab

University of Utah Emulab Testbed

GSoC March 2009 8

What is ns-3?

Ns-3 Connects Simulated Protocol Stacks Through Real Networks

realmachine

ns-3

Testbed Testbed

realmachine

ns-3

GSoC March 2009 9

Example: ORBIT

Rutgers WINLAB ORBIT Radio Grid

GSoC March 2009 10

The ns-3 GSoC Process

• Limited Number of Slots

• More Applicants than Slots (>10:1)

• We have suggestions, and accept new ideas

• Rank Initial Application– People who knew ns-3 basics ranked higher;

– People who had clearly thought about the problem ranked higher;

– Don’t just parrot the idea back;

– Show us quickly why you are “the one.”

GSoC March 2009 11

The ns-3 GSoC Process

• IRC “Interviews”

– Probe knowledge of C++, networking, past projects

– Chat about proposed project• Have you thought about the project at any level of detail?

• Do you have a reasonable scope of work in mind?

• Do you have a reasonable approach?

• How serious are you about this work?

• Does this work really interest you?

• Agreement on Scope and Schedule

• Chat Chat Chat! Communicate Communicate Communicate! Code code code.

GSoC March 2009 12

Lessons Learned

• Students had a problem creating and adhering to a schedule!

• Students need to understand this is a real full-time job– You have to interview;

– You have to get hired;

– You have to work full time;

– You have to produce something;

– You have to produce it on time;

– You have to make something that does what you said it would;

– You have to communicate with the rest of your team.

GSoC March 2009 13

Lessons Learned

• Communication is absolutely critical.– Direct correlation between levels of communication

and success

– The students that spent the most time on IRC with us had the best outcomes.

– We will heavily use IRC, Skype, etc.

– Need at least weekly coordination chats with mentors

– Daily chats if difficulties arise.

• Time is tight (10 weeks) so adherence to a real schedule is critical.

GSoC March 2009 14

Lessons Learned

• If a GSoc project is taken lightly it is a waste of time for everyone involved.

• With reasonable effort– Students can do very good work.– Students can make important contributions to

the project– Everybody can benefit– Everybody can learn

GSoC March 2009 15

ns-3 and GSoC

Short Q & A