Nonce is a parameter that varies with time. A nonce can be a time stamp, a visit counter on a Web page, or a special marker. In security engineering, a nonce is a number used once. Nonce is often a random number issued in an authentication protocol to ensure that old communication cannot be reused in replay attacks.
The nonce of Edge Proxy (EP) in Service Agent (SA) 2.0 is global, and not specific to each device.