Cisco: Simple configuration of IP multicast dense mode

Until now, I did not meet a network engineer to be really “in love” with multicast. Some are considering challenging, interesting, useful but most of the network engineers (I repeat myself, from the persons that I discussed with) are rather preferring do other topics that multicast. If you are curious about my position in regarding multicast, well I’m somewhere in the middle. I consider it challenging, a topic for the future (like IPv6), I MUST know it, but let’s say that is not my strongest topic in networking.

I think that I can share some of my experience here with you, and maybe discuss a little bit on th multicast subject. And since I do not want to enter more complex multicast configuration from the start I said I should take it slow with the easiest one: multicast dense mode configuration. As you know there is also sparse mode configuration which can be configured in a more complex way, and I will do it in next tutorials. For now I only hope that you know what is multicast and words like PIM, IGMP, dense-mode, sparse-mode does not sound like alien descriptions for you. If you are feeling insecure about this topic, please check this link as you might get very good information about IP multicast.

For this tutorial I have a simple point to point router connection (R1 and R2) with a subnet of /24 in between, and each router has an additional host (R1 has the multicast sender connected and R2 has the multicast reveiver connected). Since I have no possibility to test the IP multicast traffic in this configuration, the explanation above is just to have a picture about the environment. I hope that for the multicast sparse mode I will find a way to generate some multicast traffic, when I will write the tutorial somewhere next weeks.

Please see the tutorial by clicking the image below:

Multicast dense mode

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Calin is a network engineer, with more than 20 years of experience in designing, installing, troubleshooting, and maintaining large enterprise WAN and LAN networks.

6 thoughts on “Cisco: Simple configuration of IP multicast dense mode”

  1. I am doing my Masters in Telecom at CU-Boulder.
    I really liked your tutorial, as I am about start project on IPv6 multicasting for video conferencing . Hope you start something on IPv6 multicasting too..

  2. I need to implement IPTV with small existing LAN network. I have 3560 IP Base core switch and 2960 LAN Lite image access switch. Can somebody help me doing configuration for multicasting on both the switches. Access switch is directly connected with IP Base core switch, do I need to configure Stub Routing on Core switch or some VLANs can resolve my problem by only enabling IP Multicast distribution? Please guys give your valuable suggestions for this issue.

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