A Discrete-Event Network Simulator
API
realtime-udp-echo.py
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1 #
2 # * This program is free software; you can redistribute it and/or modify
3 # * it under the terms of the GNU General Public License version 2 as
4 # * published by the Free Software Foundation;
5 # *
6 # * This program is distributed in the hope that it will be useful,
7 # * but WITHOUT ANY WARRANTY; without even the implied warranty of
8 # * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
9 # * GNU General Public License for more details.
10 # *
11 # * You should have received a copy of the GNU General Public License
12 # * along with this program; if not, write to the Free Software
13 # * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
14 
15 # Network topology
16 #
17 # n0 n1 n2 n3
18 # | | | |
19 # =================
20 # LAN
21 #
22 # - UDP flows from n0 to n1 and back
23 # - DropTail queues
24 # - Tracing of queues and packet receptions to file "udp-echo.tr"
25 
26 import ns.applications
27 import ns.core
28 import ns.csma
29 import ns.internet
30 import ns.network
31 
32 def main(argv):
33  #
34  # Allow the user to override any of the defaults and the above Bind() at
35  # run-time, via command-line arguments
36  #
37  cmd = ns.core.CommandLine()
38  cmd.Parse(argv)
39 
40  #
41  # But since this is a realtime script, don't allow the user to mess with
42  # that.
43  #
44  ns.core.GlobalValue.Bind("SimulatorImplementationType", ns.core.StringValue("ns3::RealtimeSimulatorImpl"))
45 
46  #
47  # Explicitly create the nodes required by the topology (shown above).
48  #
49  print ("Create nodes.")
50  n = ns.network.NodeContainer()
51  n.Create(4)
52 
53  internet = ns.internet.InternetStackHelper()
54  internet.Install(n)
55 
56  #
57  # Explicitly create the channels required by the topology (shown above).
58  #
59  print ("Create channels.")
60  csma = ns.csma.CsmaHelper()
61  csma.SetChannelAttribute("DataRate", ns.network.DataRateValue(ns.network.DataRate(5000000)))
62  csma.SetChannelAttribute("Delay", ns.core.TimeValue(ns.core.MilliSeconds(2)));
63  csma.SetDeviceAttribute("Mtu", ns.core.UintegerValue(1400))
64  d = csma.Install(n)
65 
66  #
67  # We've got the "hardware" in place. Now we need to add IP addresses.
68  #
69  print ("Assign IP Addresses.")
70  ipv4 = ns.internet.Ipv4AddressHelper()
71  ipv4.SetBase(ns.network.Ipv4Address("10.1.1.0"), ns.network.Ipv4Mask("255.255.255.0"))
72  i = ipv4.Assign(d)
73 
74  print ("Create Applications.")
75 
76  #
77  # Create a UdpEchoServer application on node one.
78  #
79  port = 9 # well-known echo port number
80  server = ns.applications.UdpEchoServerHelper(port)
81  apps = server.Install(n.Get(1))
82  apps.Start(ns.core.Seconds(1.0))
83  apps.Stop(ns.core.Seconds(10.0))
84 
85  #
86  # Create a UdpEchoClient application to send UDP datagrams from node zero to
87  # node one.
88  #
89  packetSize = 1024
90  maxPacketCount = 500
91  interPacketInterval = ns.core.Seconds(0.01)
92  client = ns.applications.UdpEchoClientHelper(i.GetAddress (1), port)
93  client.SetAttribute("MaxPackets", ns.core.UintegerValue(maxPacketCount))
94  client.SetAttribute("Interval", ns.core.TimeValue(interPacketInterval))
95  client.SetAttribute("PacketSize", ns.core.UintegerValue(packetSize))
96  apps = client.Install(n.Get(0))
97  apps.Start(ns.core.Seconds(2.0))
98  apps.Stop(ns.core.Seconds(10.0))
99 
100  ascii = ns.network.AsciiTraceHelper()
101  csma.EnableAsciiAll(ascii.CreateFileStream("realtime-udp-echo.tr"))
102  csma.EnablePcapAll("realtime-udp-echo", False)
103 
104  #
105  # Now, do the actual simulation.
106  #
107  print ("Run Simulation.")
108  ns.core.Simulator.Run()
109  ns.core.Simulator.Destroy()
110  print ("Done.")
111 
112 if __name__ == '__main__':
113  import sys
114  main(sys.argv)