multicast server into existing vlan network

Posted on 2011-05-03
Last Modified: 2012-05-11

We have a network setup with 3 vlan's, one for guest access, one for corporate and one for a shared internet access.

We now need to install the multicase application i.e. one sender with multiple recievers, and my initial plan was to create another VLAN for this to seperate the traffic from the other VLAN's. Now i don't know much about multicase other than the concept i.e. you subscribe to a broadcast rather than the server sending multi requests to it's subscribers, it sends one broadcast and you subscrib to see the broadcast to see the video.

I'm just tryting to get a head start before they turn up to install the application.

Now can i put the multicast class D into a VLAN and do i need too.

The provider has said i should try to use a address range from to Now i don't fully understand the class D address, do they have subnet masks. For instance if i wanted to define a VLAN for for 254 hosts i thought the subnet would be the same as a class C address but our layer 3 netgear switch (GSM7328) complains that the address is not in the same subnet as the gateway.

I also seen i should enable IGMP snooping on our layer 2 switches, and also configure a IGMP query device on our core layer 3 switch, any advice welcome on this as well.

Thanks in advance

Question by:pskemp
    LVL 44

    Assisted Solution

    by:Craig Beck
    The switches need to have IGMP snooping enabled on any VLAN where a multicast source is present.
    You don't need to create a new VLAN for the multicast server - just configure the server with an IP on whichever VLAN you want to connect it to, and enable IGMP snooping for all VLANs on your switch.
    LVL 1

    Author Comment

    Thanks for the response criagbeck.

    The multicast source doesn't need to be present on any of the existing vlan's, as it's a standalone system. Saying that one of the VLAN's needs to access the multicast source server through IP, although i'm unsure what they need to do at this stage.

    The multicast source will be using the same network infrastructure as the existing VLAN's, so the main aim it to minimise the interruption the multicast system is going to have on the rest of the network, which is why i thought of using the vlan.

    Is there any downside to putting the multicast setup in a VLAN and if so what would the correct subnet mask assuming a starting address of for 254 hosts equivliant of in a class C address subnet.
    LVL 44

    Accepted Solution

    There should be no downside to putting the server into its own VLAN, and you don't need to configure the Multicast address usually - there will be an option in the application on the server which lets you set the base Multicast address, but nothing more.

    The important part is that you can see the server on the network using its Unicast IP address (the normal IP address bound to the NIC) and that the server is reachable by hosts on different VLANs (if you decide to put the server on its own VLAN).
    LVL 1

    Author Comment

    Thanks for that Craigbeck.

    Sorry for the late reply.

    Ok so the server tiself will get an base multicast address aswell as a unicast address. The mutlicast address will be a class D address, can the unicast address be class c address.

    So on the vlan, i would just put the unicast address into the vlan. The IGMP snooping would handle ensuring the mutlicast traffic doesn't swamp/interfere with the normal network traffic. I would need to enable routing on the vlan to enable the other vlans to see this server and then use ACL to ensure my guest network can't see the multicast server as i do for the corporate network.

    Sorry for all the questions but thanks so much for your help.

    Cheers Paul.
    LVL 67

    Expert Comment

    This question has been classified as abandoned and is closed as part of the Cleanup Program. See the recommendation for more details.

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