Vlan multicast question

[James Pilcher]

Hi all,

This is my 1st post so please bare with me if I missed any common forum decorum.

project:

I need to allow 3 vm's multicast packet propagation within a server cluster where network latency is low enough to ensure that most multicast messages reach their destination and TTL is high enough to ensure core routers do not discard packets.

This environment relies heavily on L3 switching (static routes - L,C,S) with no real routing protocol enabled, within multiple VLANs. A 4500 series switch is providing the core intra-vlan route translation.

My thoughts were to create another vlan for the 3vm's and allow multicast packets only inside that vlan and use switchport access to ensure devices from other vlans have access. 

My questions are:

1.) If I enable multicast routing on the 4500 can I limit multicast packets broadcast to a single vlan?

2.) Is it best to use auto-rp with an IP access-list or sparse-mode or some other configuration? 

3.) will this change impact the other vlans currently in my environment?

I can provide sh run or other information on how the router is configured as requested.

Thanks for your input,

James

[Richard Burts · Accepted solution]

James

Perhaps there are parts of your environment that I do not understand and that would change the approach. But if I am understanding correctly you are talking about creating a VLAN for the vm's and their multicast traffic. If the multicast is to be limited to a single VLAN then there is no need to enable multicast routing and therefore no need to worry about auto-rp or sparse mode or any other multicast configuration options. By default the multicast will be forwarded to all devices in that VLAN and will not be forwarded outside of that VLAN. Seems to me from your description that is what you want to achieve.

If I have missed something or did not understand correctly then please clarify.

HTH

Rick

[James Pilcher]

Thanks Rick,

I appreciate the confirmation. That is exactly what I wanted to achieve but needed to verify the impact before continuing.

James.

[Richard Burts]

James

I am glad that my response was helpful. Sometimes there is a simple way to achieve what we want and this is one of those cases. Thank you for using the rating system to mark this question as answered. This will help other readers in the forum to identify a thread in which there is helpful information.

HTH

Rick