diff --git a/udp/udp-client-server.py b/udp/udp-client-server.py
new file mode 100644
index 0000000..33e9f18
--- /dev/null
+++ b/udp/udp-client-server.py
@@ -0,0 +1,121 @@
+import ns.core
+import ns.applications
+import ns.internet
+import ns.csma
+
+def main(argv):
+	ns.core.LogComponentEnable("UdpClient", ns.core.LOG_LEVEL_INFO)
+	ns.core.LogComponentEnable("UdpServer", ns.core.LOG_LEVEL_INFO)
+	cmd = ns.core.CommandLine ()
+	cmd.useIpv6 = "False"
+	cmd.AddValue ("useIpv6", "Use Ipv6")
+	cmd.Parse (argv)
+	
+	print "Create nodes."
+	n = ns.network.NodeContainer ()
+	n.Create (2)
+	
+	internet = ns.internet.InternetStackHelper ()
+	internet.Install (n)
+
+	print "Create channels."
+	csma = ns.csma.CsmaHelper ()
+	csma.SetChannelAttribute ("DataRate", ns.core.StringValue ("5000000"))
+	csma.SetChannelAttribute ("Delay", ns.core.TimeValue (ns.core.MilliSeconds (2)))
+	csma.SetDeviceAttribute ("Mtu", ns.core.UintegerValue (1400))
+	d = csma.Install (n)
+
+	print "Assign IP Addresses."
+	if (cmd.useIpv6 == "False"):
+		ipv4 = ns.internet.Ipv4AddressHelper ()
+		ipv4.SetBase (ns.network.Ipv4Address ("10.1.1.0"), ns.network.Ipv4Mask ("255.255.255.0"))
+		i = ipv4.Assign (d)
+		serverAddress = ns.network.Address (i.GetAddress (1))
+	    
+	else:
+		ipv6 = ns.internet.Ipv6AddressHelper ()
+		ipv6.SetBase (ns.network.Ipv6Address ("2001:0000:f00d:cafe::"), ns.network.Ipv6Prefix (64))
+		i6 = ipv6.Assign (d)
+		serverAddress = ns.network.Address (i6.GetAddress (1, 1))
+
+	
+	print "Create Applications."
+
+
+	port = 4000  
+	server = ns.applications.UdpEchoServerHelper (port)
+	serverapps = server.Install (n.Get (1))
+	serverapps.Start (ns.core.Seconds (1.0))
+	serverapps.Stop (ns.core.Seconds (10.0))
+
+	MaxPacketSize = 1024;
+	interPacketInterval = ns.core.Seconds (0.05)
+	maxPacketCount = 320;
+
+	client = ns.applications.UdpEchoClientHelper ( serverAddress, port)
+
+
+	client.SetAttribute ("MaxPackets", ns.core.UintegerValue (maxPacketCount))
+  	client.SetAttribute ("Interval", ns.core.TimeValue (interPacketInterval))
+ 	client.SetAttribute ("PacketSize", ns.core.UintegerValue (MaxPacketSize))
+  
+	clientapps = client.Install (n.Get (0))
+	serverapps.Start (ns.core.Seconds (2.0))
+	serverapps.Stop (ns.core.Seconds (10.0))
+
+
+
+	ascii = ns.network.AsciiTraceHelper ()
+	csma.EnableAsciiAll (ascii.CreateFileStream ("udp-client-serv.tr"))
+	csma.EnablePcapAll ("udp-client-serv", False)
+	print "Run Simulation."
+	ns.core.Simulator.Run ()
+	ns.core.Simulator.Destroy ()
+	print "Done."
+
+if __name__ == '__main__':
+    import sys
+main (sys.argv)
+
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