IGMP and Multicast

[lovelyliatroim]

Hi Guys,

Devleopment machines finally arrived in and I set up the app on 2 boxes. Now the 2 nodes dont see each other for whatever reason. I ran the the jgroups tests here http://www.jgroups.org/javagroupsnew/docs/manual/html/ch02.html#ItDoesntWork and none worked so told the sys admin guy to have a look at the network setup.

He then asks me what version of IGMP do i need, reading this http://osdir.com/ml/java.javagroups.devel/2003-07/msg00009.html suggests that i dont need it??? Or do I ?? Using the jgroups lib from the 2.2GA release so thats 2.6.2.

If i dont need it then what is the next steps i should take to see why the nodes cant see each other?? I suppose start looking at wireshark!!

Cheers,
LL

[belaban]

It doesn't matter which version of IGMP you use, the stack and switches should support versions 2 and 3 (and they usually do).
You probably have a different issue, e.g.:
- firewalls dropping packets
- TTL = 0
- Incorrect interfaces (bind_addr) for sending and receiving mcasts
- VLANs dropping mcasts
- Incorrect mcast addrs (224.0.0.1 - 224.0.0.255 can be dropped by the switch !)

I suggest wireshark to see whether you're getting any mcast packets flowing between the boxes

[lovelyliatroim]

Ok Thanks for the information Bela.

Will start looking at wireshark and see whats going.

Thanks,
LL