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New Member

Multicast Application using GDA


I have a multicast problem that I think I know the awnser to, but would like to know if there is any official documentation for this issue.

I have the following switched topology.

Host A connects to sw3 and host b connects to sw4.

Host A sends a multicast stream to the GDA (Mac 1:00:5e:00:00:01 - same as all-hosts-onsubnet mac) and host B does not receive it.

Inswitches, this MAC has speacial meaning for processing, ie, it has to go to the system port!! To get this working, would I have to put a static cam entry in sw3 to point to sw1 and then in sw1 to poing to sw2 (if that was the prefered path?)

The simple solution is for the devlopers to change their code, but you know what developers are like ;)

router1 router2

| |

| |

| VLAN x |

sw1 sw2

|| ||

|| ||


| hosta |

| |



Many thx indeed.

New Member

Re: Multicast Application using GDA

cant do pics on the formum page, just for you info, sw1, sw2, sw3 and sw4 are all in one VLAN. we are talking about a host on sw3 in vlan x sending a udp stream and the other host on sw4 in the same vlan, not receiveing it.

They say a picture paints a thousand words :))

Re: Multicast Application using GDA


if the hosts are in the same VLAN they should be able to send/receive multicasts with default setting - no manual address configuration necessary.

Are you able to ping from one host to the other?

If yes, try to connect protocol analyzer on the receiving port and see if the multicasts are really coming. The easiest way is to run Ethereal ( - freeware) on the host. If not, check if the multicast are sent out from the first host (again - running Ethereal is the easiest way).

BTW, it's pretty stupid to use 1:00:5e:00:00:01 as a multicast address by any application but you know that.



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