NetSim Support Portal

IP multicast is a method of sending Internet Protocol (IP) datagrams to a group of interested receivers in a single transmission. It is the IP-specific form of multicast and is used for streaming media and other network applications.

NetSim emulator allows sending real traffic via the virtual network modeled in its environment. The real packets will experience the effect of the network conditions modeled in NetSim's virtual network in addition to the real network. This is usually achieved by setting the system hosting NetSim emulator as the gateway in the systems that are the sources of traffic.

Consider the following network setup where there are two systems running JPERF client and server applications and one system running NetSim emulator.

In the above network the gateway/nexthop of System 1 (and system 2 if traffic is bi-directional) needs to be set as System 3 for packets to reach NetSim Emulator prior to reaching the destination. NetSim can then take care of sending the real packets over the virtual network modeled in its design environment. 

However, this works only in case of simple application models such as Unicast. In case of application models such as Multicast NetSim offers different techniques to ensure that the packets go through the emulated network prior to reaching the destination devices.

NetSim provides a Multicast Emulation Client application specifically to perform multicast emulation. This application can be found in the install directory of NetSim within as shown below:

Following is an example related to performing multicast emulation in NetSim. This example involves 4 real PC's 

SYSTEM SETUP

• SYSTEM 1 - NetSim Emulator (IP:192.168.0.34)
• SYSTEM 2 - Source (iperf Client) (IP:192.168.0.11)
• SYSTEM 3 - Destination 1 (iperf server 1) (IP:192.168.0.36)
• SYSTEM 4 - Destination 2 (iperf server 2) (IP: 192.168.0.19)
• All 4 systems must be in a single network

System 1:

Step 1: Install NetSim Standard version including Emulator License

Step 2: Run NetSim, open Internetworks create a scenario as shown below.

Step 3: Create Multicast Emulation with following properties:

Application Method: Multicast

Application Type: Emulation

Device Count: Count of devices which act as multicast server and client. 3 in this case(excludes the system hosting netsim emulator, includes the iperf client and two iperf servers)

Device ID: The ID's of the virtual devices representing the multicast clients and servers.

Multicast Dest Address: The multicast IP address to which nodes are listening

Device Real IP: The IP Address of all the systems involved in Multicast (Excluding the system running NetSim emulator)

Destination Real IP: The multicast IP Address

Source Port: Can be set to 0.

Destination Port: The port to which the server is listening

Step 4: Configure all other systems in the Network and the perform simulation

Step 5: Run the simulation

System 2:

Note: Make sure that iperf is present in your system. Please download that is attached with this article.

Step 1: Copy Multicast Emulation Client folder from NetSim installation directory to the current system.

Eg: C:\Program Files\NetSim Standard\MulticastEmulationClient

Step 2: Run iperf with the following command:iperf -c 224.1.2.3 -u -i 1 -t 1000

Step 3: Run multicastEmulationclient  in client system in command prompt in admin mode :

Command: MulticastEmulationClient.exe <Client system Ip> <Emulation server Ip> <Multicast Ip> <port>

System 3 and System 4:

Note: Make sure that iperf is present in your system. Please download that is attached with this mail.

Step 1: Copy Multicast Emulation Client folder from NetSim installation directory to the current system.

Eg: C:\Program Files\NetSim Standard\MulticastEmulationClient

Step 2: Run jperf with the following command:iperf -s -B 224.1.2.3 -u -i 1

Step 3: Run multicastEmulationclient  in client system with the following CMD:

Command:MulticastEmulationClient.exe <Client system Ip> <Emulation server Ip> <Multicast Ip> <port>

Now perform Step 5 of System 1 i.e Run the simulation in System 1. User will be asked to Enter an option to choose local IP while simulation. Please enter the option that displays the server-IP given as <multicast ip> for MulticastEmulationClient.exe. In this example its 192.168.0.34.

On successful completion of Simulation, NetSim provides performance metrics in the Simulation Results dashboard.