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Add reasonable data rate and delay to csma channels; update tutorial

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This commit is contained in:
Craig Dowell
2008-12-09 12:04:36 -08:00
parent 5168309a66
commit 4b0f97c0aa
3 changed files with 20 additions and 4 deletions
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20
doc/tutorial/building-topologies.texi
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@@ -163,10 +163,19 @@ point-to-point nodes.
We mentioned above that you were going to see a helper for CSMA devices and
channels, and the next lines introduce them. The @code{CsmaHelper} works just
like a @code{PointToPointHelper}, but it creates and connects CSMA devices and
channels.
channels. In the case of a CSMA device and channel pair, notice that the data
rate is specified by a @em{channel} attribute instead of a device attribute.
This is because a real CSMA network does not allow one to mix, for example,
10Base-T and 100Base-T devices on a given channel. We first set the data rate
to 100 megabits per second, and then set the speed-of-light delay of the channel
to 6560 nano-seconds (arbitrarily chosen as 1 nanosecond per foot over a 100
meter segment). Notice that you can set an attribute using its native data
type.
@verbatim
CsmaHelper csma;
csma.SetChannelAttribute ("DataRate", StringValue ("100Mbps"));
csma.SetChannelAttribute ("Delay", TimeValue (NanoSeconds (6560)));
NetDeviceContainer csmaDevices;
csmaDevices = csma.Install (csmaNodes);
@@ -698,12 +707,15 @@ that will get CSMA devices. The node in question is going to end up with a
point-to-point device and a CSMA device. We then create a number of ``extra''
nodes that compose the remainder of the CSMA network.
We then instantiate a @code{CsmaHelper} and a @code{NetDeviceContainer} to
keep track of the CSMA net devices. Then we @code{Install} CSMA devices on
the selected nodes.
We then instantiate a @code{CsmaHelper} and set its attributes as we did in
the previous example. We create a @code{NetDeviceContainer} to keep track of
the created CSMA net devices and then we @code{Install} CSMA devices on the
selected nodes.
@verbatim
CsmaHelper csma;
csma.SetChannelAttribute ("DataRate", StringValue ("100Mbps"));
csma.SetChannelAttribute ("Delay", TimeValue (NanoSeconds (6560)));
NetDeviceContainer csmaDevices;
csmaDevices = csma.Install (csmaNodes);

2
examples/second.cc
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@@ -59,6 +59,8 @@ main (int argc, char *argv[])
p2pDevices = pointToPoint.Install (p2pNodes);
CsmaHelper csma;
csma.SetChannelAttribute ("DataRate", StringValue ("100Mbps"));
csma.SetChannelAttribute ("Delay", TimeValue (NanoSeconds (6560)));
NetDeviceContainer csmaDevices;
csmaDevices = csma.Install (csmaNodes);

2
examples/third.cc
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@@ -65,6 +65,8 @@ main (int argc, char *argv[])
csmaNodes.Create (nCsma);
CsmaHelper csma;
csma.SetChannelAttribute ("DataRate", StringValue ("100Mbps"));
csma.SetChannelAttribute ("Delay", TimeValue (NanoSeconds (6560)));
NetDeviceContainer csmaDevices;
csmaDevices = csma.Install (csmaNodes);