RFC 3588:Diameter Base Protocol
RFC-Ref

semantic


Click on the red underlined text to get to the source

... originate Reject messages in cases where policies are violated. As a result, proxies need to understand the semantics of the messages passing through them, and may not support all Diameter applications. ...
... AVPs. As a result, relays never originate messages, do not need to understand the semantics of messages or non-routing AVPs, and are ...



Google
Web
RFC-Ref