Now we have a topology built, but we need applications.  This section is

Now we have a topology built, but we need applications.  This section is

going to be fundamentally similar to the applications section of 

going to be fundamentally similar to the applications section of 

@code{first.cc} but we are going to instantiate the server on one of the 

@code{first.cc} but we are going to instantiate the server on one of the 

point-to-point device.

point-to-point device.

First, we set up the echo server.  We create a @code{UdpEchoServerHelper} and

First, we set up the echo server.  We create a @code{UdpEchoServerHelper} and

Since we have actually built an internetwork here, we need some form of 

Since we have actually built an internetwork here, we need some form of 

internetwork routing.  @command{ns-3} provides what we call a global route 

internetwork routing.  @command{ns-3} provides what we call a global route 

manager to set up the routing tables on nodes.  This route manager has a 

manager to set up the routing tables on nodes.  This route manager has a 

the hard work of setting up routing for you.  

the hard work of setting up routing for you.  

Basically, what happens is that each node behaves as if it were an OSPF router

Basically, what happens is that each node behaves as if it were an OSPF router

@verbatim

@verbatim

  PointToPointHelper::EnablePcapAll ("second");

  PointToPointHelper::EnablePcapAll ("second");

@end verbatim

@end verbatim

The CSMA network is a multi-point-to-point network.  This means that there 

The CSMA network is a multi-point-to-point network.  This means that there 

network and ask it to perform a promiscuous sniff of the network, thereby

network and ask it to perform a promiscuous sniff of the network, thereby

emulating what @code{tcpdump} would do.  If you were on a Linux machine

emulating what @code{tcpdump} would do.  If you were on a Linux machine

you might do something like @code{tcpdump -i eth0} to get the trace.  

you might do something like @code{tcpdump -i eth0} to get the trace.  

parameter to true enables promiscuous captures.

parameter to true enables promiscuous captures.

The last section of code just runs and cleans up the simulation just like

The last section of code just runs and cleans up the simulation just like

@verbatim

@verbatim

  export NS_LOG=

  export NS_LOG=

  ./waf --run scratch/mysecond

  ./waf --run scratch/mysecond

Since we have set up the UDP echo applications to log just as we did in 

Since we have set up the UDP echo applications to log just as we did in 

@code{first.cc}, you will see similar output when you run the script.

@code{first.cc}, you will see similar output when you run the script.

is from the echo client, indicating that it has received its echo back from

is from the echo client, indicating that it has received its echo back from

the server.

the server.

files:

files:

@verbatim

@verbatim

To illustrate the difference between promiscuous and non-promiscuous traces, we

To illustrate the difference between promiscuous and non-promiscuous traces, we

also requested a non-promiscuous trace for the next-to-last node.  Go ahead and

also requested a non-promiscuous trace for the next-to-last node.  Go ahead and

@verbatim

@verbatim

  tcpdump -nn -tt -r second-100-0.pcap

  tcpdump -nn -tt -r second-100-0.pcap

For simplicity, this code uses the default PHY layer configuration and

For simplicity, this code uses the default PHY layer configuration and

channel models which are documented in the API doxygen documentation for

channel models which are documented in the API doxygen documentation for

methods. Once these objects are created, we create a channel object

methods. Once these objects are created, we create a channel object

and associate it to our PHY layer object manager to make sure

and associate it to our PHY layer object manager to make sure

wireless medium and can communication and interfere:

wireless medium and can communication and interfere:

@verbatim

@verbatim

@end verbatim

@end verbatim

The file ``third-0-0.pcap'' corresponds to the point-to-point device on node

The file ``third-0-0.pcap'' corresponds to the point-to-point device on node

corresponds to the point-to-point device on node one -- the right side of the

corresponds to the point-to-point device on node one -- the right side of the

mode) trace from the Wifi network and the file ``third-1-1.pcap'' will be the

mode) trace from the Wifi network and the file ``third-1-1.pcap'' will be the

promiscuous trace from the CSMA network.  Can you verify this by inspecting

promiscuous trace from the CSMA network.  Can you verify this by inspecting

the code?

the code?

@uref{http://www.nsnam.org/doxygen-release/index.html,,ns-3 Doxygen}

@uref{http://www.nsnam.org/doxygen-release/index.html,,ns-3 Doxygen}

which you can find in the ``Modules'' tab.

which you can find in the ``Modules'' tab.

Under the ``core'' section, you will find a link to ``The list of all trace 

Under the ``core'' section, you will find a link to ``The list of all trace 

traces yourself.  Additionally in the ``Modules'' documentation, there is

traces yourself.  Additionally in the ``Modules'' documentation, there is

any of these @code{Attributes} via the command line as we have previously 

any of these @code{Attributes} via the command line as we have previously 

discussed.

discussed.

@end verbatim

@end verbatim

to build the project.  So now if you look in the directory 

to build the project.  So now if you look in the directory 

above.  You can take a look at the contents of these files and find that they

above.  You can take a look at the contents of these files and find that they

do include all of the public include files in their respective modules.

do include all of the public include files in their respective modules.

We will use this statement as a convenient place to talk about our Doxygen

We will use this statement as a convenient place to talk about our Doxygen

documentation system.  If you look at the project web site, 

documentation system.  If you look at the project web site, 

taken to our documentation page.

taken to our documentation page.

Along the left side, you will find a graphical representation of the structure

Along the left side, you will find a graphical representation of the structure

helper.

helper.

Applications require a time to ``start'' generating traffic and may take an

Applications require a time to ``start'' generating traffic and may take an

@code{ApplicationContainer} methods @code{Start} and @code{Stop}.  These 

@code{ApplicationContainer} methods @code{Start} and @code{Stop}.  These 

methods take @code{Time} parameters.  In this case, we use an explicit C++

methods take @code{Time} parameters.  In this case, we use an explicit C++

conversion sequence to take the C++ double 1.0 and convert it to an 

conversion sequence to take the C++ double 1.0 and convert it to an 

The source code is mainly in the @code{src} directory.  You can view source

The source code is mainly in the @code{src} directory.  You can view source

code either by clicking on the directory name or by clicking on the @code{files}

code either by clicking on the directory name or by clicking on the @code{files}

link to the right of the directory name.  If you click on the @code{src}

link to the right of the directory name.  If you click on the @code{src}

click on @code{core} subdirectory, you will find a list of files.  The first file

click on @code{core} subdirectory, you will find a list of files.  The first file

you will find (as of this writing) is @code{abort.h}.  If you 

you will find (as of this writing) is @code{abort.h}.  If you 

click on @code{abort.h} link, you will be sent to the source file for @code{abort.h}.

click on @code{abort.h} link, you will be sent to the source file for @code{abort.h}.

Our example scripts are in the @code{examples} directory.  The source code for

Our example scripts are in the @code{examples} directory.  The source code for

the helpers we have used in this chapter can be found in the 

the helpers we have used in this chapter can be found in the 

get a feel for what is there and the style of @command{ns-3} programs.

get a feel for what is there and the style of @command{ns-3} programs.

@cindex tarball

@cindex tarball

The @command{ns-3} code is available in Mercurial repositories on the server

The @command{ns-3} code is available in Mercurial repositories on the server

@uref{http://www.nsnam.org/releases/}, or you can work with repositories

@uref{http://www.nsnam.org/releases/}, or you can work with repositories

using Mercurial.  We recommend using Mercurial unless there's a good reason

using Mercurial.  We recommend using Mercurial unless there's a good reason

not to.  See the end of this section for instructions on how to get a tarball

not to.  See the end of this section for instructions on how to get a tarball

@cindex repository

@cindex repository

The simplest way to get started using Mercurial repositories is to use the

The simplest way to get started using Mercurial repositories is to use the

@code{ns-3-allinone} environment.  This is a set of scripts that manages the 

@code{ns-3-allinone} environment.  This is a set of scripts that manages the 

recommend that you begin your @command{ns-3} adventures in this environment

recommend that you begin your @command{ns-3} adventures in this environment

as it can really simplify your life at this point.

as it can really simplify your life at this point.

the more constant ns-3-dev here in the tutorial, but you can replace the 

the more constant ns-3-dev here in the tutorial, but you can replace the 

string ``ns-3-dev'' with your choice of release (e.g., ns-3.4 and 

string ``ns-3-dev'' with your choice of release (e.g., ns-3.4 and 

ns-3.4-ref-traces) in the text below.  You can find the latest version  of the

ns-3.4-ref-traces) in the text below.  You can find the latest version  of the

Go ahead and change into the @code{ns-3-allinone} directory you created when

Go ahead and change into the @code{ns-3-allinone} directory you created when

you cloned that repository.  We are now going to use the @code{download.py} 

you cloned that repository.  We are now going to use the @code{download.py} 

Go ahead and type the following into your shell (remember you can substitute

Go ahead and type the following into your shell (remember you can substitute

the name of your chosen release number instead of @code{ns-3-dev} -- like

the name of your chosen release number instead of @code{ns-3-dev} -- like

  mkdir tarballs

  mkdir tarballs

  cd tarballs

  cd tarballs

  wget http://www.nsnam.org/releases/ns-allinone-3.4.tar.bz2

  wget http://www.nsnam.org/releases/ns-allinone-3.4.tar.bz2

@end verbatim 

@end verbatim 

If you change into the directory @code{ns-allinone-3.4} you should see a

If you change into the directory @code{ns-allinone-3.4} you should see a

number of files:

number of files:

@verbatim

@verbatim

@end verbatim 

@end verbatim 

You are now ready to build the @command{ns-3} distribution.

You are now ready to build the @command{ns-3} distribution.

@end verbatim

@end verbatim

Note the last part of the above output.  Some ns-3 options are not enabled by

Note the last part of the above output.  Some ns-3 options are not enabled by

For instance, to enable XmlTo, the library libxml-2.0 must be found on the

For instance, to enable XmlTo, the library libxml-2.0 must be found on the

system.  in the example above, this library was not found and the corresponding

system.  in the example above, this library was not found and the corresponding

feature was not enabled.  There is a feature to use sudo to set the suid bit of

feature was not enabled.  There is a feature to use sudo to set the suid bit of

available in waf.  To explore these options, type:

available in waf.  To explore these options, type:

@verbatim

@verbatim

@end verbatim

@end verbatim

We'll use some of the testing-related commands in the next section.

We'll use some of the testing-related commands in the next section.

@cindex regression tests

@cindex regression tests

You can also run our regression test suite to ensure that your distribution and

You can also run our regression test suite to ensure that your distribution and

known-good reference output files.  You downloaded these reference traces to 

known-good reference output files.  You downloaded these reference traces to 

your machine during the download process above.  (Warning:  The @code{ns-3.2} 

your machine during the download process above.  (Warning:  The @code{ns-3.2} 

and @code{ns-3.3} releases do not use the @code{ns-3-allinone} environment

and @code{ns-3.3} releases do not use the @code{ns-3-allinone} environment

has gone awry.  If the error was discovered in a pcap file, it will be useful

has gone awry.  If the error was discovered in a pcap file, it will be useful

to convert the pcap files to text using tcpdump prior to comparison.

to convert the pcap files to text using tcpdump prior to comparison.

is not present.

is not present.

To run the regression tests, you provide Waf with the regression flag.

To run the regression tests, you provide Waf with the regression flag.

@end verbatim

@end verbatim

Waf first checks to make sure that the program is built correctly and 

Waf first checks to make sure that the program is built correctly and 

produces the following output.

produces the following output.

@verbatim

@verbatim

order to extend the system in most cases.

order to extend the system in most cases.

For those interested in the gory details of Waf, the main web site can be 

For those interested in the gory details of Waf, the main web site can be 

@node Development Environment

@node Development Environment

@section Development Environment

@section Development Environment

@cindex MinGW

@cindex MinGW

If you do use Cygwin or MinGW; and use Logitech products, we will save you

If you do use Cygwin or MinGW; and use Logitech products, we will save you

quite a bit of heartburn right off the bat and encourage you to take a look

quite a bit of heartburn right off the bat and encourage you to take a look

@cindex Logitech

@cindex Logitech

Search for ``Logitech'' and read the FAQ entry, ``why does make often 

Search for ``Logitech'' and read the FAQ entry, ``why does make often 

We will assume a basic facility with the Berkeley Sockets API in the examples

We will assume a basic facility with the Berkeley Sockets API in the examples

used in this tutorial.  If you are new to sockets, we recommend reviewing the

used in this tutorial.  If you are new to sockets, we recommend reviewing the

API and some common usage cases.  For a good overview of programming TCP/IP

API and some common usage cases.  For a good overview of programming TCP/IP

There is an associated web site that includes source for the examples in the

There is an associated web site that includes source for the examples in the

book, which you can find at:

book, which you can find at:

not have access to a copy of the book, the echo clients and servers shown in 

not have access to a copy of the book, the echo clients and servers shown in 

the website above) you will be in good shape to understand the tutorial.

the website above) you will be in good shape to understand the tutorial.

There is a similar book on Multicast Sockets,

There is a similar book on Multicast Sockets,

that covers material you may need to understand if you look at the multicast 

that covers material you may need to understand if you look at the multicast 

examples in the distribution.

examples in the distribution.

example, to print more information by setting its logging level via the 

example, to print more information by setting its logging level via the 

NS_LOG environment variable.  

NS_LOG environment variable.  

the``VARIABLE=value'' syntax.  If you are using a csh-like shell, then you 

the``VARIABLE=value'' syntax.  If you are using a csh-like shell, then you 

will have to convert my examples to the ``setenv VARIABLE value'' syntax 

will have to convert my examples to the ``setenv VARIABLE value'' syntax 

required by those shells.

required by those shells.

You now know that you can enable all of the logging for this component by

You now know that you can enable all of the logging for this component by

setting the @code{NS_LOG} environment variable to the various levels.  Let's

setting the @code{NS_LOG} environment variable to the various levels.  Let's

informational level log message is @code{NS_LOG_INFO}.  Go ahead and add one 

informational level log message is @code{NS_LOG_INFO}.  Go ahead and add one 

(just before we start creating the nodes) that tells you that the script is 

(just before we start creating the nodes) that tells you that the script is 

``Creating Topology.''  This is done as in this code snippet,

``Creating Topology.''  This is done as in this code snippet,

This simple two line snippet is actually very useful by itself.  It opens the

This simple two line snippet is actually very useful by itself.  It opens the

door to the @command{ns-3} global variable and @code{Attribute} systems.  Go 

door to the @command{ns-3} global variable and @code{Attribute} systems.  Go 

the start of @code{main}.  Go ahead and build the script and run it, but ask 

the start of @code{main}.  Go ahead and build the script and run it, but ask 

the script for help in the following way,

the script for help in the following way,

setting in the @code{PointToPointHelper} above.  Let's use the default values 

setting in the @code{PointToPointHelper} above.  Let's use the default values 

for the point-to-point devices and channels by deleting the 

for the point-to-point devices and channels by deleting the 

@code{SetDeviceAttribute} call and the @code{SetChannelAttribute} call from 

@code{SetDeviceAttribute} call and the @code{SetChannelAttribute} call from 

Your script should now just declare the @code{PointToPointHelper} and not do 

Your script should now just declare the @code{PointToPointHelper} and not do 

any @code{set} operations as in the following example,

any @code{set} operations as in the following example,

  #include <fstream>

  #include <fstream>

@end verbatim

@end verbatim

@verbatim

@verbatim

  std::ofstream ascii;

  std::ofstream ascii;

@end verbatim

@end verbatim

The first two lines are just vanilla C++ code to open a stream that will be

The first two lines are just vanilla C++ code to open a stream that will be

are unfamiliar with this code.  The last line of code in the snippet above

are unfamiliar with this code.  The last line of code in the snippet above

tells @command{ns-3} that you want to enable ASCII tracing on all 

tells @command{ns-3} that you want to enable ASCII tracing on all 

point-to-point devices in your simulation; and you want the (provided) trace

point-to-point devices in your simulation; and you want the (provided) trace

created in a script.  Just as a filesystem may have directories under the 

created in a script.  Just as a filesystem may have directories under the 

root, we may have node numbers in the @code{NodeList}.  The string 

root, we may have node numbers in the @code{NodeList}.  The string 

@code{/NodeList/0} therefore refers to the zeroth node in the @code{NodeList}

@code{/NodeList/0} therefore refers to the zeroth node in the @code{NodeList}

devices that have been installed.  This list appears next in the namespace.

devices that have been installed.  This list appears next in the namespace.

You can see that this trace event comes from @code{DeviceList/0} which is the 

You can see that this trace event comes from @code{DeviceList/0} which is the 

zeroth device installed in the node. 

zeroth device installed in the node. 

  00 r 

  00 r 

  01 2.25732 

  01 2.25732 

  02 /NodeList/1/DeviceList/0/$ns3::PointToPointNetDevice/MacRx 

  02 /NodeList/1/DeviceList/0/$ns3::PointToPointNetDevice/MacRx 

@end verbatim

@end verbatim

Notice that the trace operation is now @code{r} and the simulation time has

Notice that the trace operation is now @code{r} and the simulation time has

 and a ``.pcap'' suffix.

 and a ``.pcap'' suffix.

In our example script, we will eventually see files named ``myfirst-0-0.pcap'' 

In our example script, we will eventually see files named ``myfirst-0-0.pcap'' 

node 1-device 0, respectively.

node 1-device 0, respectively.

Once you have added the line of code to enable pcap tracing, you can run the

Once you have added the line of code to enable pcap tracing, you can run the

  2.257324 IP 10.1.1.2.9 > 10.1.1.1.49153: UDP, length 1024

  2.257324 IP 10.1.1.2.9 > 10.1.1.1.49153: UDP, length 1024

@end verbatim

@end verbatim

echo packet is sent at 2 seconds into the simulation.  If you look at the

echo packet is sent at 2 seconds into the simulation.  If you look at the

at 2.257324 seconds.  You see the packet being echoed back at 2.257324 seconds

at 2.257324 seconds.  You see the packet being echoed back at 2.257324 seconds

in the second dump, and finally, you see the packet being received back at 

in the second dump, and finally, you see the packet being received back at 

the client in the first dump at 2.514648 seconds.

the client in the first dump at 2.514648 seconds.