Add randomness to prevent dropped packets due to incast

diff --git a/src/simulation/simulation.cc b/src/simulation/simulation.cc
index 3e49af2e8e719aacea797607b9509d8142d995a7..e429e7cd31f800c3ccf799d381458ec55135a258 100644 (file)
--- a/src/simulation/simulation.cc
+++ b/src/simulation/simulation.cc
@@ -51,7 +51,7 @@ void capture_state(std::ostream& file, LinkLayerHelper::Network& n){
        }
 }
 
-void setup(LinkLayerHelper::Network& n, Topology& t, std::istream& file){
+void setup(LinkLayerHelper::Network& n, Topology& t, std::istream& file, bool random){
 
        uint16_t port = 9;   // Discard port (RFC 863)
 
@@ -106,8 +106,14 @@ void setup(LinkLayerHelper::Network& n, Topology& t, std::istream& file){
                        UdpClientHelper helper(n.interfaces[destination].GetAddress(0), port);
                        helper.SetAttribute("MaxPackets", UintegerValue(packets));
                        ApplicationContainer app = helper.Install(n.hostNodes.Get(source));
-                       app.Start (Seconds (time));
 
+                       if(random){
+                               long ntime = rand() % 1000;
+                               Time rtime = Seconds(time) + MilliSeconds(source) + NanoSeconds(ntime);
+                               app.Start (rtime);
+                       } else {
+                               app.Start (Seconds (time));
+                       }
                }
        }
 
@@ -135,6 +141,7 @@ try {
        std::string dataFile;
        std::string stateFile;
        std::string linkLayer = "moose";
+       std::string randomize = "yes";
 
        CommandLine cmd;                        // Allow CommandLine args
        cmd.AddValue("link", "Link Layer? (moose|ethernet) [moose]", linkLayer);
@@ -144,6 +151,7 @@ try {
        cmd.AddValue("network", "Network Topology File", networkFile);
        cmd.AddValue("data", "Network Data File", dataFile);
        cmd.AddValue("state", "Bridge State File", stateFile);
+       cmd.AddValue("randomize", "Randomize Start Times", randomize);
        cmd.Parse (argc, argv);
 
        std::ifstream networkStream(networkFile.c_str(), std::ifstream::in);
@@ -189,7 +197,17 @@ try {
 
        }
 
-       setup(n, t, dataStream);
+       bool random;
+
+       if(randomize == "yes"){
+               random = true;
+       } else if(randomize == "no"){
+               random = false;
+       } else {
+               throw new std::runtime_error("Unknown randomize setting.");
+       }
+       
+       setup(n, t, dataStream, random);
 
        // Tracing