Real World Application Integration

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Revision as of 13:56, 7 May 2008 by Liujatp (Talk | contribs) (some notes)

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Project Background

The goal of this proposed project is to develop frameworks and strategies that enable people to integrate already existing code into the simulator. Depending on the application, this can be a straightforward or laborious process, but still should be preferable in many cases to rewriting these protocols from scratch, and hopefully this project can come up with techniques to make these ports even easier.

Here are some initial pointers to how this problem has been worked in the past:

Gsoc Project

Liu Jian( started the gsoc project from April 2008.


The purpose of the project is to develop frameworks and strategies that enable people to integrate already existing code into the ns-3 simulator, it will be accomplished by integrating Quagga, a routing deamon which implement many useful routing protocols. The project will begin by learning experence that Quagga ever ported to INET simulator, then porting Quagga to ns3 by adding some patchings, through the porting job, summariced,documented and structured properly, a adaption layer or some methodologies for ns-3 will be implemented, through which other real world application will be easily ported by the next person.

Project Plan

  • looking at quagga to identify the system calls it use.functions like socket, time, signal,etc.
  • implememt these function as simu_* in the ns-3-simu tree.
  • porting quagga to ns3.


  • listed all system functions which quagga calls. there is about 30 funs of total 150 need to be implemented in ns-3-simu.

After investigation, there were 4 types of functions.

  • next: implement these simu_xxx functions(there would be a great job)

started by simple server/client demo code from running in ns-3-simu and test simu_x APIs.

  • .......

Detail Schedule

  • ~-4.30 read quagga source code, compile and run simple test; list simu_xxx sys-calls; finish the first step
  • 5.1~5.4 four days vacation
  • ......

About Quagga

basic knowledge

Quagga is a routing soute of 5 routing protocols(RIP,RIPng,OSPFv2,OSPFv3,BGP) based on Zebra, they can be run simutaneously or separately.Zebra layer that contains what is known as the "Routing Information Base" or RIB. Zebra is responsible for maintaining the RIB and for writing routes from the RIB into the kernel forwarding table.

Quagga was planned to use multi-threaded mechanism when it runs with a kernel that supports multi-threads. There may be several protocol-specific routing daemons and zebra the kernel routing manager.The ripd daemon handles the RIP protocol, while ospfd is a daemon which supports OSPF version 2. bgpd supports the BGP-4 protocol. For changing the kernel routing table and for redistribution of routes between different routing protocols, there is a kernel routing table manager zebra daemon. Quagga system architecture, see here

see more information here:

some notes

1, Firstly, if we donot care about how one of the protocols runs, we can get some idea about the main code-structure here, which would be useful for porting to ns3.

  • the main thread maintains thead_master, which contains all threads triggered from event, timer, I/O, background,etc; when all initial work was finished, the whole application run as event-driven mode like below:
  • Actually there were only one thread running at this time, it use the signal functions of application-defined, many timer functions of the basic protocol-application , and select(2)system all to monitor I/O operations for multiplexing the events.

2, started with Zebra.