GE - EGD Modify Multicast Address

Hi,
Wondering if anyone has had experience/knows how to modify the multicast address of EGD Data being produced.

My PLC has
Producer Id: 10.30.44.152
ETM : 10.30.44.152

The multicast address is 224.0.7.1 <- I am wondering if it is possible to modify this?

We have two people running EGD servers on our network and I think it may cause havoc if we are using the same IPs

Lincoln

linkau said:

Hi,

The multicast address is 224.0.7.1 <- I am wondering if it is possible to modify this?

Lincoln

Click to expand...

Have you wiresharked this? I think that may be the multicast group address rather than the address your devices are multicasting to. Do you see any packets being sent 239.30.44.152?

shawn_75 said:

Have you wiresharked this? I think that may be the multicast group address rather than the address your devices are multicasting to. Do you see any packets being sent 239.30.44.152?

Click to expand...

Really I think I am wasting peoples time here. I need to understand how Multicast works 100% before asking questions.

That's the real issue I have.

linkau said:

Really I think I am wasting peoples time here. I need to understand how Multicast works 100% before asking questions.

That's the real issue I have.

Click to expand...

No, you're not. Ask away.

My multicast experience is only as far as a local LAN segment. I cannot speak to mulitcasting across routers. I have 10 cameras multicasting on my LAN with an IGMP querier running to manage the groups. If you wireshark you network with the filter "igmp", you'll see all the querier messages and should be able to determine which IP addresses are group addresses and which are your servers.

I don't have a link to it since Emerson bought GE's PLC division but you need to get a copy of manual GFK2224Z PACS Ethernet Manual.

Gives you more than you want to know about multicast. If I remember correctly, the producer ID is what sets the multicast address.

You do not need to change the values of ip 224.0.7.1, as they are reserved addresses. What you need to do is keep both of them in the same group id, but each PLC must contain a unique exchange id.