Hi Jakub!
L-PI2X-AS-50 is an "Assurance License", it is how many Netflow capable devices you want to connect.
The feature enables you to see which protocol mix there are in your network, e-2-e performance,
application troubleshhoting and metrics collection etc. Handy if you have mission critical applications
and the budget for it. Smallest license is 25 devices (ex a router or WLC)
L-PI2X-GW is a new feature for automatic deployment/configuration of wired devices only.
A new Cisco device will prompt the network for a PnP Gateway, and if present, th Gw
will supply a predefined template. Have not had time to play with this one myself yet...