iSCSI rescan problem

Hello.

we just installed a new VNX 7600 in our datacenter.

For a couple of months we'll use it as iSCSI target. When we install the new blades chassis, we'll switch to FC.

I have a question to help us with a problem we have. I'm trying to open a ticket, but waiting for the support to make sense of our account lol.

So here is my case.

we have the following config:

180 esx 5.5 hosts in 10 clusters. Each 4 NICs (2 management, 2 storage)

NetAPP SAN with iscsi targets

They are all in a /22 (255.255.252.0) network in dedicated switches.

Everything worked fine.

Then we plugged the EMC on the same network and began presenting LUNs.

Now the hosts can't rescan, it never finishes, HOsts disconnects from vCenter. LUNs don"t appear on all the hosts.

The EMC has 4 IPs in the /22 network and we use them all in the ESX software iscsi adapter.

The EMC technician made the initial config so we thought this was a best practice.

What would you recommend so we can use it.

Would it be to create 2 new vLANs on the dedicated switches and move the EMC in it?

is our problem broadcast related?

Thanks.