What is the use of z/ip gateway (dhcp server) allocating ip's for z wave nodes?



Every z wave node has to reach by zip gateway,So when sending data from z/wave client(pc,mobile app) we will send to the zip gateway with node information (which node to be on/off).
So now z/ip gateway, sends the same node information via uart/usb to the connected controller(z wave chip) and through which it controls the z wave devices via RF.

So still i have a confusion why zip gateway trying to create ip address’s to nodes(as already z wave controller will assign node is’s for the devices and for itself and same communicated to z/ip gateway)…?