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

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