[Linux-cluster] Re: Multicasting problems

Alan A alan.zg at gmail.com
Thu Sep 10 15:12:57 UTC 2009


On Tue, Sep 8, 2009 at 5:34 PM, Alan A <alan.zg at gmail.com> wrote:

> It has come to the point where our cluster production configuration has
> halted due to the unexpected issues with multicasting on LAN/WAN.
>
> The problem is that the firewall enabled on the switch ports does not
> support multicasting, and between cluster nodes and the routers lays
> firewall.
>
> Nodes -> Switch with integrated Firewall devices -> Router
>
> We are aware of problems encountered with Cisco switches and are trying to
> clear some things. For instance in RHEL Knowledgebase article 5933 it
> states:
>
> *The recommended method is to enable multicast routing for a given vlan so
> that the Catalyst will act as the IGMP querier. This consists of the
> following steps:*
>
> * *
>
>    1.
>
>    *Enabling multicast on the switch globally*
>    2.
>
>    *Choosing the vlan the cluster nodes are using*
>    3.
>
>    *Turning on PIM routing for that subnet*
>
>
> My Questions:
>
> Can we enable PIM routing on the Server NIC itself without using dedicated
> network device? Meaning IGMP multicast would be managed by the NIC's itself
> from each node, can the nodes awarnes function this way?
>
> Any suggestions on how to get around firewall issue without purchesing
> firewalls with routing tables?
>
> Cisco switch model is: switch 6509 running 12.2(18) SXF and IGMP v2.
>
>
>
> --
> Alan A.
>

Problem is resolved - this is what we did after we found this article:

http://www.cisco.com/en/US/products/hw/switches/ps708/products_tech_note09186a008059a9df.shtml



What we did is assign the multicast mac address to the switch ports X, Y, Z,
as described in that article under solution number 4:

Solution 4: Configure Static Multicast MAC Entries on All the Switches

You can make a static content-addressable memory (CAM) entry for the
multicast MAC address on all the switches for all the receiver ports and the
downstream switch ports. Any switch obeys the static CAM entry rules and
sends the packet out all the interfaces that are specified in the CAM table.
This is the least-scalable solution for an environment that has a lot of
multicast applications.

    Switch1(config)#mac-address-table static 0100.5e6f.efef vlan 1 interface

    gigabitethernet 2/46 gigabitethernet 2/48

    !--- Note: This command should be on one line.

    Switch1#show mac-address-table multicast vlan 1

     vlan   mac address     type   learn qos             ports
    -----+---------------+--------+-----+---+--------------------------------

       1  0100.5e6f.efef    static  Yes          -   Gi2/46,Gi2/48


    Switch2(config)#mac-address-table static 0100.5e6f.efef vlan 1 interface

    fastethernet 1/0/47

    !--- Note: This command should be on one line.

    Switch2#show mac-address-table multicast vlan 1
    Vlan    Mac Address       Type       Ports
    ----    -----------       ----       -----
       1    0100.5e6f.efef    USER        Fa1/0/47


Cluster is operational, the cost is 0$.

-- 
Alan A.
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