David, They're layer 3. The situation is that the IPs were registered on one VSWITCH, and passed on to real switches in the external network. Later, another host registered the same IPs on a different VSWITCH, which failed to pass them on to the external network (rejected because they were dups). The 2nd VSWITCH detected this error, but retained the IPs (for itself) anyway. The question is whether the 2nd VSWITCH should have retained them given it knew they were dups. Mark
Date: Mon, 2 May 2011 10:32:30 -0500 From: dbo...@sinenomine.net Subject: Re: Duplicate IPs on VSWITCHes - Feature or Defect To: IBMVM@LISTSERV.UARK.EDU Are these layer 2 or layer 3? If layer 2, then they are (and should be) paying zero attention to the IP address. Layer 2 cares only about MAC addresses. Layer 3 is more subtle. Technically a real switch should attempt only to insert the address in the forwarding table and then the latest entry wins (eg it should eject the previously registered host as ARP entries expire in the communicating guests with cached info about IP to MAC mappings). So, I’d say that if you are using layer 2 switches, it is neither a bug nor a feature. It’s working correctly, and it’s your problem to avoid this situation. In the layer 3 case, it’s arguably doing the right thing, but there is a case for it dropping the first registration when a new host registers the same address.
