Simulating a Multicast Host and Multicast Receiver in a Test Environment , Cisco Routers

Rakesh Madupu JNCIE-SP #02079 CCIE-SP#47613Network Development Engineer
Hello All,

I have been training on Multicast for a while now and whenever I start the topic , I find out that my friends /  Colleagues mention that they do not know how to test Multicast Joins. As most of the multicast would be video traffic and they should technically have a whole slew of setup to send and receive some video traffic.

Simple way to do it in a Cisco router is as follows. This applies for all the multicast modes

1. Sparse Mode
2. Dense Mode
3. Sparse-Dense Mode

The below is the topology that I will be using, Please note for the article sake to be more productive , I have chosen emulation with GNS3 itself.


R1 will be the multicast server, R4 will be the multicast receiver.

What has been assumed in this simulation is :

1. There is an IGP , in this case EIGRP running between r1,r5 and r5
2. There is Pim dense mode (any mode of your choice) running and devices are pim adj

Now, on the server end, in order to generate traffic, a simple Ping can be used as follows:

r1#ping repeat 100
                      Type escape sequence to abort.
                      Sending 100, 100-byte ICMP Echos to, timeout is 2 seconds:

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You you will see, the pings are failing, because there isn't a host who wants to receive this traffic. So, how do I make R4 as the host ? Now, by using the below command on any interface of R4 , I will use fa0/1

r4(config)#int fa0/1
                      r4(config-if)#ip igmp join-group

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As soon as I do that, I try the ping again, and can now see the response below on R1 again

r1#ping repeat 100
                      Type escape sequence to abort.
                      Sending 100, 100-byte ICMP Echos to, timeout is 2 seconds:
                      Reply to request 55 from, 96 ms
                      Reply to request 56 from, 76 ms
                      Reply to request 57 from, 52 ms

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This is how you simulate a client and server in your test bed environments or while you are learning this technology without actually having a video server / video clients to receive the actual feeds.

Hope this helps for newbies who wants to learn more and more of this Important technology.

Thank you

Comments (1)

Steve MartinNetwork Operations Lead

I know this was created quite some time ago but thank you! Currently working on testing a configuration that we will be deploying into a live environment with several intricate variables and this allowed me to generate the multicast needed to ensure proper packet flows. Thanks!

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