topic Multicast address ranges with virtual connect in BladeSystem - General

Multicast address ranges with virtual connect

Michael Pye — Mon, 28 May 2012 13:58:23 GMT

We have built several Red Hat clusters on BL465 g7 blades, using the RHEL5 Cluster Suite software. The basic premise of thie cluster software is that the nodes contact each other using a private multicast IP of 239.192.x.x. We have several blades on the cisco catalyst blade switch (not virtual connect) where this works fine.

But on VC Flex-10 modules, these ranges cannot be used, and the nodes never see each. If I change the multicast IP to 239.0.0.1, then the nodes can see each other again. This happens with or without IGMP snooping enabled in VC.

My suspicion is that virtual connect does not forward multicast packets for the 239.192.x.x multicast range. Can anyone comfirm if this is true or not, and why would it be the case if so ?

Re: Multicast address ranges with virtual connect

Hongjun Ma — Wed, 30 May 2012 06:12:02 GMT

what's VC version? for earlier release with igmp snooping on, there were some issues.

http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?locale=en_US&objectID=c02535509

I know you mentioned that you see the problem with or without IGMP snooping.

the address should work fine. I suggest you open an HP support case for further troubleshooting.

Re: Multicast address ranges with virtual connect

Michael Pye — Wed, 30 May 2012 21:31:20 GMT

Interesting advisory there, thanks for the response. I have one two-node cluster that both nodes use VC version is 3.30 , and another two-node cluster with 3.51 one node and 3.18 the other node. They all exhitbit this problem. Does sound like maybe a case for HP. There must be other vc users running red hat clusters that have this problem?

Re: Multicast address ranges with virtual connect

Hongjun Ma — Wed, 30 May 2012 21:34:37 GMT

if you want to dig in further, try enable igmp snooping and do the following command for enc0:1 or end0:2(VC-1 or VC2). also, you can set up port monitoring on VC to sniff the traffic.

->show igmp-group enc0:1

===========================================

Port Group IP Address MAC Address

===========================================

d6:c 224.224.224.224 01:00:5e:60:e0:e0

d8:c 224.224.224.224 01:00:5e:60:e0:e0

d9:c 224.224.224.224 01:00:5e:60:e0:e0

d1:c 239.193.0.107 01:00:5e:41:00:6b

d1:c 239.192.0.107 01:00:5e:40:00:6b

d1:a 239.255.255.253 01:00:5e:7f:ff:fd

d2:a 239.255.255.253 01:00:5e:7f:ff:fd