To Simulate Internet Service Provider (ISP) protocols projects in NS3 has includes to emulate the numerous protocols and services used by ISPs to handle network traffic, deliver services, and making sure connectivity. Some common protocols and services in ISP networks has contain BGP (Border Gateway Protocol) for inter-domain routing, MPLS (Multiprotocol Label Switching) for effective packet forwarding, DNS for domain name resolution, and DHCP for dynamic IP addressing.
Here’s how we can simulate ISP protocols projects in NS3, concentrates on BGP for inter-domain routing and DNS for domain name resolution.
Step-by-Step Implementation
- Simulating BGP (Border Gateway Protocol) for ISPs in NS3
BGP is vital for ISPs because it permits the routing among diverse autonomous systems (ASes), enabling them to exchange routing information and regulate the best path for data transmission.
To replicate BGP in NS3, that need to incoporate Quagga or FRRouting (FRR) using the DCE (Direct Code Execution) module, as mentioned in previous BGP simulations.
Here’s a brief overview of how to set up BGP using NS3-DCE:
Steps:
- Install NS3-DCE and Quagga.
- Set up the network topology with routers acting as ASes.
- Configure BGP on each router using Quagga configuration files.
- Simulate traffic between ASes using UDP/TCP applications.
This setup permits to simulate an ISP’s use of BGP for inter-domain routing.
For a detailed BGP example, refer to the previous BGP simulation using NS3 guide.
- Simulating DNS (Domain Name System) in NS3
ISPs deliver DNS services to translate domain names into IP addresses. We can emulate DNS behavior in NS3 by generating a custom DNS application or using built-in mechanisms.
Example: Simulating DNS in NS3
This sample demonstrates on how to emulate DNS-like behavior using a simple name resolution service.
#include “ns3/core-module.h”
#include “ns3/network-module.h”
#include “ns3/internet-module.h”
#include “ns3/point-to-point-module.h”
#include “ns3/applications-module.h”
using namespace ns3;
int main (int argc, char *argv[])
{
// Step 1: Create nodes (ISP network with a DNS server and a client)
NodeContainer nodes;
nodes.Create (3); // One DNS server, two client nodes
// Step 2: Set up point-to-point links
PointToPointHelper p2p;
p2p.SetDeviceAttribute (“DataRate”, StringValue (“10Mbps”));
p2p.SetChannelAttribute (“Delay”, StringValue (“2ms”));
NetDeviceContainer devices;
devices = p2p.Install (nodes.Get (0), nodes.Get (1)); // DNS server to client 1
devices.Add (p2p.Install (nodes.Get (0), nodes.Get (2))); // DNS server to client 2
// Step 3: Install the Internet stack on all nodes
InternetStackHelper internet;
internet.Install (nodes);
// Step 4: Assign IP addresses to simulate ISP internal network
Ipv4AddressHelper ipv4;
ipv4.SetBase (“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces = ipv4.Assign (devices);
// Step 5: Create a UDP Echo server (DNS-like behavior) on node 0 (DNS server)
UdpEchoServerHelper echoServer (53); // Port 53 for DNS
ApplicationContainer serverApps = echoServer.Install (nodes.Get (0)); // Server on node 0
serverApps.Start (Seconds (1.0));
serverApps.Stop (Seconds (20.0));
// Step 6: Set up UDP Echo clients (DNS queries) on node 1 and node 2
UdpEchoClientHelper echoClient (interfaces.GetAddress (0), 53); // DNS server is node 0
echoClient.SetAttribute (“MaxPackets”, UintegerValue (1));
echoClient.SetAttribute (“Interval”, TimeValue (Seconds (1.0)));
echoClient.SetAttribute (“PacketSize”, UintegerValue (512));
ApplicationContainer clientApps1 = echoClient.Install (nodes.Get (1)); // Client on node 1
clientApps1.Start (Seconds (2.0));
clientApps1.Stop (Seconds (10.0));
ApplicationContainer clientApps2 = echoClient.Install (nodes.Get (2)); // Client on node 2
clientApps2.Start (Seconds (3.0));
clientApps2.Stop (Seconds (10.0));
// Step 7: Run the simulation
Simulator::Run ();
Simulator::Destroy ();
return 0;
}
Key Points:
- DNS-like behavior: A UDP Echo server is used to emulate a DNS server responding to queries from clients.
- Port 53: DNS traditionally performs on port 53, which is used in this example.
- UDP communication: DNS queries and responses are sent using UDP.
Running the Simulation:
- Build and Run:
./waf configure
./waf build
./waf –run dns-simulation
Extensions:
- We can adjust the script to contain real DNS resolution by executing a custom DNS application.
- Add multiple DNS servers and use load balancing to emulate DNS redundancy.
- Simulating MPLS (Multiprotocol Label Switching) for ISPs in NS3
MPLS is used by ISPs for efficient packet forwarding through their networks. MPLS allocates labels to packets that routers utilize to forward packets without needing to look at the IP header.
Since NS3 does not have direct MPLS support, we can mimic MPLS-like behavior by generating label-switched paths (LSPs) using static routes or IP tunneling.
Example: Simulating MPLS-like Behavior Using Static Routes
We can generate LSPs by setting up the static routes on each router.
#include “ns3/core-module.h”
#include “ns3/network-module.h”
#include “ns3/internet-module.h”
#include “ns3/point-to-point-module.h”
#include “ns3/applications-module.h”
using namespace ns3;
int main (int argc, char *argv[])
{
// Step 1: Create nodes (simulating ISP routers)
NodeContainer routers;
routers.Create (3); // Three routers
// Step 2: Create point-to-point links between routers
PointToPointHelper p2p;
p2p.SetDeviceAttribute (“DataRate”, StringValue (“1Gbps”));
p2p.SetChannelAttribute (“Delay”, StringValue (“2ms”));
NetDeviceContainer devices01 = p2p.Install (routers.Get (0), routers.Get (1)); // R0 to R1
NetDeviceContainer devices12 = p2p.Install (routers.Get (1), routers.Get (2)); // R1 to R2
// Step 3: Install the Internet stack on all routers
InternetStackHelper internet;
internet.Install (routers);
// Step 4: Assign IP addresses
Ipv4AddressHelper ipv4;
ipv4.SetBase (“10.1.1.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces01 = ipv4.Assign (devices01);
ipv4.SetBase (“10.1.2.0”, “255.255.255.0”);
Ipv4InterfaceContainer interfaces12 = ipv4.Assign (devices12);
// Step 5: Set up static routing to simulate MPLS-like label-switched paths (LSPs)
Ipv4StaticRoutingHelper staticRouting;
Ptr<Ipv4StaticRouting> staticRouting0 = staticRouting.GetStaticRouting (routers.Get (0)->GetObject<Ipv4> ());
staticRouting0->AddNetworkRouteTo (“10.1.2.0”, “255.255.255.0”, “10.1.1.2”, 1); // R0 -> R1 -> R2
Ptr<Ipv4StaticRouting> staticRouting1 = staticRouting.GetStaticRouting (routers.Get (1)->GetObject<Ipv4> ());
staticRouting1->AddNetworkRouteTo (“10.1.2.0”, “255.255.255.0”, “10.1.2.2”, 1); // R1 -> R2
// Step 6: Set up traffic application
UdpEchoServerHelper echoServer (9);
ApplicationContainer serverApps = echoServer.Install (routers.Get (2)); // Server on R2
serverApps.Start (Seconds (1.0));
serverApps.Stop (Seconds (10.0));
UdpEchoClientHelper echoClient (interfaces12.GetAddress (1), 9);
echoClient.SetAttribute (“MaxPackets”, UintegerValue (1));
echoClient.SetAttribute (“Interval”, TimeValue (Seconds (1.0)));
echoClient.SetAttribute (“PacketSize”, UintegerValue (1024));
ApplicationContainer clientApps = echoClient.Install (routers.Get (0)); // Client on R0
clientApps.Start (Seconds (2.0));
clientApps.Stop (Seconds (10.0));
// Step 7: Run the simulation
Simulator::Run ();
Simulator::Destroy ();
return 0;
}
Key Points:
- Static routing: Static routes are utilized to simulate label-switched paths (LSPs) in an MPLS-like network.
- UDP Echo: The UDP Echo server and client emulate traffic via the LSP.
Summary:
- BGP: Can be simulated in NS3 using Quagga or FRR integrated with NS3-DCE to simulate inter-domain routing among ISPs.
- DNS: Emulate a simple DNS functionality using UDP applications, and prolong it with real DNS resolution logic.
- MPLS: MPLS-like behaviour can be replicated using static routes to generate label-switched paths among ISP routers.
In this process, we had detailed covered the information about Internet Service Provider simulation procedures and evaluation process of Internet Service Provider outcomes across the ns3 tool. Further details regarding the Internet Service Provider will be provided in upcoming manuals.
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