"multicast routing" between two Private Vlans

Discussion in 'Networking & Security' started by bill2455, Jul 9, 2013.

  1. bill2455

    bill2455 [H]Lite

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    Are there any reason(s) a network administrator wouldn't want to allow "multicast routing" between two Private Vlans (Vlan1 and Vlan10) in different subnets operating on L3 (3750) switch network - with no outside access the web - all intranet traffic?

    thanks in advance

    2455
     
  2. jameslr

    jameslr n00b

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    Jul 8, 2013
    There could be a myriad of reasons. It all depends on what the purpose of the pvlans are. Providing a little more substance might help answer the questions better, but the short answer is likely "because they don't need to." Enabling multicast routing unless it's required is an extra step.

    This might shed some light on what is involved in enabling multicast routing on the 3750 series:
    http://www.cisco.com/en/US/docs/swi...se/configuration/guide/swmcast.html#wp1024278
     
  3. Pinski

    Pinski Limp Gawd

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    Are we talking about SSM? Or are we talking RP based Multicasting?

    What kind of multicast traffic are we talking about? It also exposes another hole for an attack on your router if you have it improperly configured, and can easily cause your router(which looks like a L3 Switch) to just drop if policies aren't correctly applied.
     
  4. bill2455

    bill2455 [H]Lite

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    TCP/IP traffic from RFID Reader - sending

    Web service: standard TCP/IP via (Winsock)
     
  5. bill2455

    bill2455 [H]Lite

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    handled something like this:

    If the devices are using multicast then you will need to turn multicast routing on the switch to allow the device and server to communicate on different Vlans. By default the switch will not route multicast packets to different Vlans. Remove the trunks since you will only need access ports. To troubleshoot if the devices are communicating use these commands.

    show ip mroute
    show ip igmp detail

    Conf t
    !
    ip multicast-routing
    !
    int range gi1/0/5 - 6
    switchport mode access
    switchport access vlan 63
    no switchport trunk native vlan 63
    no switchport trunk allow vlan 63
    !
    int vlan 1
    ip pim dense-mode
    !
    int vlan 63
    ip pim dense-mode
    !
    end

    let me know your thoughts please

    2455