The Georgia Tech Network Simulator (GTNetS) ECE6110 August 25, 2008OverviewNetwork Simulation Basics - 1Network Simulation Basics - 2Network Simulation Basics - 3GTNetS Designed Like Real NetworksGTNetS Design PhilosophyGTNetS Details - NodeGTNetS Details - PacketGTNetS ApplicationsGTNetS ProtocolsGTNetS RoutingGTNetS Support ObjectsGTNetS Distributed SimulationExampleIntegration of Zebra bgpd into ns-2/GTNetSBGP++ scalabilityOther BGP++ featuresScalability Results - PSCQuestions?The Georgia Tech Network The Georgia Tech Network SimulatorSimulator(GTNetS)(GTNetS)ECE6110ECE6110August 25, 2008August 25, 2008George F. RileyOverviewOverviewNetwork Simulation BasicsGTNetS Design PhilosophyGTNetS DetailsBGP++Scalability ResultsFAQFuture PlansDemos2Network Simulation Basics Network Simulation Basics - 1- 1Discrete Event Simulation◦Events model packet transmission, receipt, timers, etc.◦Future events maintained in sorted Event List◦Processing events results in zero or more new eventsPacket transmit event generates a future packet receipt event at next hop3Network Simulation Basics Network Simulation Basics - 2- 2Create Topology◦Nodes, Links, Queues, Routing, etc.Create Data Demand on Network◦Web Browsers, FTP transfers, Peer-to-Peer Searching and Downloads, On--Off Data Sources, etc.Run the SimulationAnalyze Results4Network Simulation Basics Network Simulation Basics - 3- 35TCP Client 1TCP Client 2TCP Server 1TCP Server 2100 Mbps, 5ms100 Mbps, 5ms100 Mbps, 5ms100 Mbps, 5ms10 Mbps, 20msGTNetS Designed Like Real GTNetS Designed Like Real NetworksNetworksNodes have one or more Interfaces◦Interfaces have IP Address and Mask◦Interfaces have an associated Link objectPackets append and remove PDU’sClear distinction between protocol stack layersPacket received at an Interface◦Forwards to Layer 2 protocol object for processing◦Forwards to Layer 3 based on protocol number (800 is IPV4)◦Forwards to Layer 4 based on protocol number (6 is TCP)◦Forwards to application based on port number6GTNetS Design PhilosophyGTNetS Design PhilosophyWritten Completely in C++Released as Open SourceAll network modeling via C++ objectsUser Simulation is a C++ main programInclude our supplied “#include” filesLink with our supplied librariesRun the resulting executable7GTNetS Details - NodeGTNetS Details - Node8NodeInterfaceQueueLinkL2 ProtocolInterfaceQueueLinkL2 ProtocolRouting InfoLocationPort MapGTNetS Details - PacketGTNetS Details - Packet9PacketUnique IDSizeTimestampHeader Header Header HeaderGTNetS ApplicationsGTNetS ApplicationsWeb Browser (based on Mah’1997)Web Server - including Gnutella GCacheOn-Off Data SourceFTP File TransferBulk Data Sending/ReceivingGnutella Peer-to-PeerSyn FloodUDP StormInternet WormsVOIP10GTNetS ProtocolsGTNetS ProtocolsTCP, complete client/server◦Tahoe, Reno, New-Reno◦Sack (in progress)◦Congestion Window, Slow Start, Receiver WindowUDPIPV4 (IPV6 Planned)IEEE 802.3 (Ethernet and point-to-point)IEEE 802.11 (Wireless)Address Resolution Protocol (ARP)ICMP (Partial)11GTNetS RoutingGTNetS RoutingStatic (pre-computed routes)Nix-Vector (on-demand)Manual (specified by simulation application)EIGRPBGPOSPFDSRAODV12GTNetS Support ObjectsGTNetS Support ObjectsRandom Number Generation◦Uniform, Exponential, Pareto, Sequential, Emiprical, ConstantStatistics Collection◦Histogram, Average/Min/MaxCommand Line Argument ProcessingRate, Time, and IP Address Parsing◦Rate(“10Mb”), Time(“10ms”)◦IPAddr(“192.168.0.1”)13GTNetS Distributed GTNetS Distributed SimulationSimulationSplit topology model into several partsEach part runs on separate workstation or separate CPU in SMPEach simulator has complete topology picture◦“Real” nodes and “Ghost” nodesTime management and message exchange via Georgia Tech “Federated Developers Kit”.Allows larger topologies that single simulationMay run faster14ExampleExampleUNC Chapel Hill, Feb 3, 2006 15// Simple GTNetS example// George F. Riley, Georgia Tech, Winter 2002#include "simulator.h" // Definitions for the Simulator Object#include "node.h" // Definitions for the Node Object#include "linkp2p.h" // Definitions for point-to-point link objects#include "ratetimeparse.h" // Definitions for Rate and Time objects#include "application-tcpserver.h" // Definitions for TCPServer application#include "application-tcpsend.h" // Definitions for TCP Sending app#include "tcp-tahoe.h" // Definitions for TCP Tahoeint main(){ // Create the simulator object Simulator s; // Create and enable IP packet tracing Trace* tr = Trace::Instance(); // Get a pointer to global trace object tr->IPDotted(true); // Tr ace IP addresses in dotted notation tr->Open("intro1.txt"); // Create the trace file TCP::LogFlagsText(true); // Log TCP flags in text mode IPV4::Instance()->SetTrace(Trace::ENABLED);// Enable IP tracing all nodes // Create the nodes Node* c1 = new Node(); // Client node 1 Node* c2 = new Node(); // Client node 2 Node* r1 = new Node(); // Router node 1 Node* r2 = new Node(); // Router node 2 Node* s1 = new Node(); // Server node 1 Node* s2 = new Node(); // Server node 2 // Create a link object template, 100Mb bandwidth, 5ms delay Linkp2p l(Rate("100Mb"), Time("5ms")); // Add the links to client and server leaf nodes c1->AddDuplexLink(r1, l, IPAddr("192.168.0.1")); // c1 to r1 c2->AddDuplexLink(r1, l, IPAddr("192.168.0.2")); // c2 to r1 s1->AddDuplexLink(r2, l, IPAddr("192.168.1.1")); // s1 to r2 s2->AddDuplexLink(r2, l, IPAddr("192.168.1.2")); // s2 to r2 // Create a link object template, 10Mb bandwidth, 100ms delay Linkp2p r(Rate("10Mb"), Time("100ms")); // Add the router to router link r1->AddDuplexLink(r2, r); // Create the TCP Servers TCPServer* server1 = new TCPServer(TCPTahoe()); TCPServer* server2 = new TCPServer(TCPTahoe()); server1->BindAndListen(s1, 80); // Application on s1, port 80 server2->BindAndListen(s2, 80); // Application on s2, port 80 server1->SetTrace(Trace::ENABLED); // Trace TCP actions at server1 server2->SetTrace(Trace::ENABLED); // Trace TCP actions at server2 // Create the TCP Sending Applications TCPSend* client1 = new TCPSend(TCPTahoe(c1), s1->GetIPAddr(), 80,