Dell Switch configure IP in production

Hi all, 

I have a dell switch that is in production. Currently it have just VLAN's configuration and its work fine. 

I like to configure for SNMP monitoring, and in order to do this i need some IP configuration. 

What will happen if:

1. I put gateway on it ?

2. If i put just an IP address ( do i need a gateway assignment too ? ) 

I can put public or private ip address. But the real question here is, what kind of impact it will have if i configure one of above options ? It's in production and i can't just play with it :) . 

Also, this switch is connected to the public switch where he get out on the net. 

Topology:

Switch Public ( IPconfigured, VLAN, Trunks etc ) ---------- This Switch ( Trunks, VLAN Configuredn ) ----- Servers

Thanks in advanced !