Here is the case you want to dedicate the second interface let's say eth1 to span traffic for effective profiling. The IP address must it be on the same subnet with eth0 of the appliance of different subnet.

Well I have try using same subnet on virtual environment and ISE accepted it. But if anybody there has try the real appliance give you thought please.

Basically the question is this

You need dual ip address on PSN can the IP be in the same subnet or different subnet?

Thanks.

SPAN is just an example in production environment you will want to dedicate your secondary interface as your probe source. As source it listen and at the same time IP address where dhcp request can be directed.

Within the next few weeks I will have some read gear to work with just to know you thought before their arrival.

I think the answer to PSN double ip addresses is solve from the documentation.

Hook up to page 15-3 if you are using pdf page 295 it states:

"You must configure the Ethernet interfaces using IP addresses on different subnets."

Once again Cisco documentation is a way to go most of the time..

Thanks for all you help.